idnits 2.17.1 draft-ietf-detnet-use-cases-16.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- ** The document seems to lack an IANA Considerations section. (See Section 2.2 of https://www.ietf.org/id-info/checklist for how to handle the case when there are no actions for IANA.) Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (May 15, 2018) is 2163 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- == Unused Reference: 'ACE' is defined on line 3622, but no explicit reference was found in the text == Unused Reference: 'CCAMP' is defined on line 3634, but no explicit reference was found in the text == Unused Reference: 'CPRI-transp' is defined on line 3653, but no explicit reference was found in the text == Unused Reference: 'DICE' is defined on line 3662, but no explicit reference was found in the text == Unused Reference: 'EA12' is defined on line 3665, but no explicit reference was found in the text == Unused Reference: 'HART' is defined on line 3686, but no explicit reference was found in the text == Unused Reference: 'I-D.ietf-6tisch-terminology' is defined on line 3715, but no explicit reference was found in the text == Unused Reference: 'I-D.ietf-ipv6-multilink-subnets' is defined on line 3721, but no explicit reference was found in the text == Unused Reference: 'I-D.ietf-roll-rpl-industrial-applicability' is defined on line 3732, but no explicit reference was found in the text == Unused Reference: 'I-D.thubert-6lowpan-backbone-router' is defined on line 3754, but no explicit reference was found in the text == Unused Reference: 'IEC61850-90-12' is defined on line 3773, but no explicit reference was found in the text == Unused Reference: 'IEEE8021TSN' is defined on line 3843, but no explicit reference was found in the text == Unused Reference: 'IETFDetNet' is defined on line 3849, but no explicit reference was found in the text == Unused Reference: 'ISO7240-16' is defined on line 3862, but no explicit reference was found in the text == Unused Reference: 'LTE-Latency' is defined on line 3873, but no explicit reference was found in the text == Unused Reference: 'RFC2119' is defined on line 3924, but no explicit reference was found in the text == Unused Reference: 'RFC2460' is defined on line 3929, but no explicit reference was found in the text == Unused Reference: 'RFC2474' is defined on line 3933, but no explicit reference was found in the text == Unused Reference: 'RFC3209' is defined on line 3944, but no explicit reference was found in the text == Unused Reference: 'RFC3393' is defined on line 3949, but no explicit reference was found in the text == Unused Reference: 'RFC3444' is defined on line 3960, but no explicit reference was found in the text == Unused Reference: 'RFC3972' is defined on line 3965, but no explicit reference was found in the text == Unused Reference: 'RFC4291' is defined on line 3974, but no explicit reference was found in the text == Unused Reference: 'RFC4903' is defined on line 3983, but no explicit reference was found in the text == Unused Reference: 'RFC4919' is defined on line 3987, but no explicit reference was found in the text == Unused Reference: 'RFC6282' is defined on line 4004, but no explicit reference was found in the text == Unused Reference: 'RFC6775' is defined on line 4022, but no explicit reference was found in the text == Unused Reference: 'TEAS' is defined on line 4053, but no explicit reference was found in the text == Unused Reference: 'UHD-video' is defined on line 4091, but no explicit reference was found in the text == Outdated reference: A later version (-30) exists of draft-ietf-6tisch-architecture-14 -- Obsolete informational reference (is this intentional?): RFC 2460 (Obsoleted by RFC 8200) Summary: 1 error (**), 0 flaws (~~), 31 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Internet Engineering Task Force E. Grossman, Ed. 3 Internet-Draft DOLBY 4 Intended status: Informational May 15, 2018 5 Expires: November 16, 2018 7 Deterministic Networking Use Cases 8 draft-ietf-detnet-use-cases-16 10 Abstract 12 This draft documents requirements in several diverse industries to 13 establish multi-hop paths for characterized flows with deterministic 14 properties. In this context deterministic implies that streams can 15 be established which provide guaranteed bandwidth and latency which 16 can be established from either a Layer 2 or Layer 3 (IP) interface, 17 and which can co-exist on an IP network with best-effort traffic. 19 Additional requirements include optional redundant paths, very high 20 reliability paths, time synchronization, and clock distribution. 21 Industries considered include professional audio, electrical 22 utilities, building automation systems, wireless for industrial, 23 cellular radio, industrial machine-to-machine, mining, private 24 blockchain, and network slicing. 26 For each case, this document will identify the application, identify 27 representative solutions used today, and the improvements IETF DetNet 28 solutions may enable. 30 Status of This Memo 32 This Internet-Draft is submitted in full conformance with the 33 provisions of BCP 78 and BCP 79. 35 Internet-Drafts are working documents of the Internet Engineering 36 Task Force (IETF). Note that other groups may also distribute 37 working documents as Internet-Drafts. The list of current Internet- 38 Drafts is at https://datatracker.ietf.org/drafts/current/. 40 Internet-Drafts are draft documents valid for a maximum of six months 41 and may be updated, replaced, or obsoleted by other documents at any 42 time. It is inappropriate to use Internet-Drafts as reference 43 material or to cite them other than as "work in progress." 45 This Internet-Draft will expire on November 16, 2018. 47 Copyright Notice 49 Copyright (c) 2018 IETF Trust and the persons identified as the 50 document authors. All rights reserved. 52 This document is subject to BCP 78 and the IETF Trust's Legal 53 Provisions Relating to IETF Documents 54 (https://trustee.ietf.org/license-info) in effect on the date of 55 publication of this document. Please review these documents 56 carefully, as they describe your rights and restrictions with respect 57 to this document. Code Components extracted from this document must 58 include Simplified BSD License text as described in Section 4.e of 59 the Trust Legal Provisions and are provided without warranty as 60 described in the Simplified BSD License. 62 Table of Contents 64 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 5 65 2. Pro Audio and Video . . . . . . . . . . . . . . . . . . . . . 6 66 2.1. Use Case Description . . . . . . . . . . . . . . . . . . 6 67 2.1.1. Uninterrupted Stream Playback . . . . . . . . . . . . 7 68 2.1.2. Synchronized Stream Playback . . . . . . . . . . . . 7 69 2.1.3. Sound Reinforcement . . . . . . . . . . . . . . . . . 8 70 2.1.4. Deterministic Time to Establish Streaming . . . . . . 8 71 2.1.5. Secure Transmission . . . . . . . . . . . . . . . . . 8 72 2.1.5.1. Safety . . . . . . . . . . . . . . . . . . . . . 8 73 2.2. Pro Audio Today . . . . . . . . . . . . . . . . . . . . . 9 74 2.3. Pro Audio Future . . . . . . . . . . . . . . . . . . . . 9 75 2.3.1. Layer 3 Interconnecting Layer 2 Islands . . . . . . . 9 76 2.3.2. High Reliability Stream Paths . . . . . . . . . . . . 9 77 2.3.3. Integration of Reserved Streams into IT Networks . . 9 78 2.3.4. Use of Unused Reservations by Best-Effort Traffic . . 10 79 2.3.5. Traffic Segregation . . . . . . . . . . . . . . . . . 10 80 2.3.5.1. Packet Forwarding Rules, VLANs and Subnets . . . 10 81 2.3.5.2. Multicast Addressing (IPv4 and IPv6) . . . . . . 11 82 2.3.6. Latency Optimization by a Central Controller . . . . 11 83 2.3.7. Reduced Device Cost Due To Reduced Buffer Memory . . 11 84 2.4. Pro Audio Asks . . . . . . . . . . . . . . . . . . . . . 12 85 3. Electrical Utilities . . . . . . . . . . . . . . . . . . . . 12 86 3.1. Use Case Description . . . . . . . . . . . . . . . . . . 12 87 3.1.1. Transmission Use Cases . . . . . . . . . . . . . . . 12 88 3.1.1.1. Protection . . . . . . . . . . . . . . . . . . . 12 89 3.1.1.2. Intra-Substation Process Bus Communications . . . 18 90 3.1.1.3. Wide Area Monitoring and Control Systems . . . . 19 91 3.1.1.4. IEC 61850 WAN engineering guidelines requirement 92 classification . . . . . . . . . . . . . . . . . 20 93 3.1.2. Generation Use Case . . . . . . . . . . . . . . . . . 21 94 3.1.2.1. Control of the Generated Power . . . . . . . . . 21 95 3.1.2.2. Control of the Generation Infrastructure . . . . 22 96 3.1.3. Distribution use case . . . . . . . . . . . . . . . . 27 97 3.1.3.1. Fault Location Isolation and Service Restoration 98 (FLISR) . . . . . . . . . . . . . . . . . . . . . 27 99 3.2. Electrical Utilities Today . . . . . . . . . . . . . . . 28 100 3.2.1. Security Current Practices and Limitations . . . . . 28 101 3.3. Electrical Utilities Future . . . . . . . . . . . . . . . 30 102 3.3.1. Migration to Packet-Switched Network . . . . . . . . 31 103 3.3.2. Telecommunications Trends . . . . . . . . . . . . . . 31 104 3.3.2.1. General Telecommunications Requirements . . . . . 31 105 3.3.2.2. Specific Network topologies of Smart Grid 106 Applications . . . . . . . . . . . . . . . . . . 32 107 3.3.2.3. Precision Time Protocol . . . . . . . . . . . . . 33 108 3.3.3. Security Trends in Utility Networks . . . . . . . . . 34 109 3.4. Electrical Utilities Asks . . . . . . . . . . . . . . . . 36 110 4. Building Automation Systems . . . . . . . . . . . . . . . . . 36 111 4.1. Use Case Description . . . . . . . . . . . . . . . . . . 36 112 4.2. Building Automation Systems Today . . . . . . . . . . . . 37 113 4.2.1. BAS Architecture . . . . . . . . . . . . . . . . . . 37 114 4.2.2. BAS Deployment Model . . . . . . . . . . . . . . . . 38 115 4.2.3. Use Cases for Field Networks . . . . . . . . . . . . 40 116 4.2.3.1. Environmental Monitoring . . . . . . . . . . . . 40 117 4.2.3.2. Fire Detection . . . . . . . . . . . . . . . . . 40 118 4.2.3.3. Feedback Control . . . . . . . . . . . . . . . . 41 119 4.2.4. Security Considerations . . . . . . . . . . . . . . . 41 120 4.3. BAS Future . . . . . . . . . . . . . . . . . . . . . . . 41 121 4.4. BAS Asks . . . . . . . . . . . . . . . . . . . . . . . . 42 122 5. Wireless for Industrial . . . . . . . . . . . . . . . . . . . 42 123 5.1. Use Case Description . . . . . . . . . . . . . . . . . . 42 124 5.1.1. Network Convergence using 6TiSCH . . . . . . . . . . 43 125 5.1.2. Common Protocol Development for 6TiSCH . . . . . . . 43 126 5.2. Wireless Industrial Today . . . . . . . . . . . . . . . . 44 127 5.3. Wireless Industrial Future . . . . . . . . . . . . . . . 44 128 5.3.1. Unified Wireless Network and Management . . . . . . . 44 129 5.3.1.1. PCE and 6TiSCH ARQ Retries . . . . . . . . . . . 46 130 5.3.2. Schedule Management by a PCE . . . . . . . . . . . . 47 131 5.3.2.1. PCE Commands and 6TiSCH CoAP Requests . . . . . . 47 132 5.3.2.2. 6TiSCH IP Interface . . . . . . . . . . . . . . . 48 133 5.3.3. 6TiSCH Security Considerations . . . . . . . . . . . 49 134 5.4. Wireless Industrial Asks . . . . . . . . . . . . . . . . 49 135 6. Cellular Radio . . . . . . . . . . . . . . . . . . . . . . . 49 136 6.1. Use Case Description . . . . . . . . . . . . . . . . . . 49 137 6.1.1. Network Architecture . . . . . . . . . . . . . . . . 49 138 6.1.2. Delay Constraints . . . . . . . . . . . . . . . . . . 50 139 6.1.3. Time Synchronization Constraints . . . . . . . . . . 52 140 6.1.4. Transport Loss Constraints . . . . . . . . . . . . . 54 141 6.1.5. Security Considerations . . . . . . . . . . . . . . . 54 142 6.2. Cellular Radio Networks Today . . . . . . . . . . . . . . 55 143 6.2.1. Fronthaul . . . . . . . . . . . . . . . . . . . . . . 55 144 6.2.2. Midhaul and Backhaul . . . . . . . . . . . . . . . . 55 145 6.3. Cellular Radio Networks Future . . . . . . . . . . . . . 56 146 6.4. Cellular Radio Networks Asks . . . . . . . . . . . . . . 58 147 7. Industrial M2M . . . . . . . . . . . . . . . . . . . . . . . 59 148 7.1. Use Case Description . . . . . . . . . . . . . . . . . . 59 149 7.2. Industrial M2M Communication Today . . . . . . . . . . . 60 150 7.2.1. Transport Parameters . . . . . . . . . . . . . . . . 60 151 7.2.2. Stream Creation and Destruction . . . . . . . . . . . 61 152 7.3. Industrial M2M Future . . . . . . . . . . . . . . . . . . 61 153 7.4. Industrial M2M Asks . . . . . . . . . . . . . . . . . . . 62 154 8. Mining Industry . . . . . . . . . . . . . . . . . . . . . . . 62 155 8.1. Use Case Description . . . . . . . . . . . . . . . . . . 62 156 8.2. Mining Industry Today . . . . . . . . . . . . . . . . . . 63 157 8.3. Mining Industry Future . . . . . . . . . . . . . . . . . 63 158 8.4. Mining Industry Asks . . . . . . . . . . . . . . . . . . 64 159 9. Private Blockchain . . . . . . . . . . . . . . . . . . . . . 64 160 9.1. Use Case Description . . . . . . . . . . . . . . . . . . 64 161 9.1.1. Blockchain Operation . . . . . . . . . . . . . . . . 65 162 9.1.2. Blockchain Network Architecture . . . . . . . . . . . 65 163 9.1.3. Security Considerations . . . . . . . . . . . . . . . 66 164 9.2. Private Blockchain Today . . . . . . . . . . . . . . . . 66 165 9.3. Private Blockchain Future . . . . . . . . . . . . . . . . 66 166 9.4. Private Blockchain Asks . . . . . . . . . . . . . . . . . 66 167 10. Network Slicing . . . . . . . . . . . . . . . . . . . . . . . 67 168 10.1. Use Case Description . . . . . . . . . . . . . . . . . . 67 169 10.2. DetNet Applied to Network Slicing . . . . . . . . . . . 67 170 10.2.1. Resource Isolation Across Slices . . . . . . . . . . 67 171 10.2.2. Deterministic Services Within Slices . . . . . . . . 67 172 10.3. A Network Slicing Use Case Example - 5G Bearer Network . 68 173 10.4. Non-5G Applications of Network Slicing . . . . . . . . . 68 174 10.5. Limitations of DetNet in Network Slicing . . . . . . . . 69 175 10.6. Network Slicing Today and Future . . . . . . . . . . . . 69 176 10.7. Network Slicing Asks . . . . . . . . . . . . . . . . . . 69 177 11. Use Case Common Themes . . . . . . . . . . . . . . . . . . . 69 178 11.1. Unified, standards-based network . . . . . . . . . . . . 69 179 11.1.1. Extensions to Ethernet . . . . . . . . . . . . . . . 69 180 11.1.2. Centrally Administered . . . . . . . . . . . . . . . 69 181 11.1.3. Standardized Data Flow Information Models . . . . . 70 182 11.1.4. L2 and L3 Integration . . . . . . . . . . . . . . . 70 183 11.1.5. Consideration for IPv4 . . . . . . . . . . . . . . . 70 184 11.1.6. Guaranteed End-to-End Delivery . . . . . . . . . . . 70 185 11.1.7. Replacement for Multiple Proprietary Deterministic 186 Networks . . . . . . . . . . . . . . . . . . . . . . 70 187 11.1.8. Mix of Deterministic and Best-Effort Traffic . . . . 71 188 11.1.9. Unused Reserved BW to be Available to Best Effort 189 Traffic . . . . . . . . . . . . . . . . . . . . . . 71 190 11.1.10. Lower Cost, Multi-Vendor Solutions . . . . . . . . . 71 192 11.2. Scalable Size . . . . . . . . . . . . . . . . . . . . . 71 193 11.3. Scalable Timing Parameters and Accuracy . . . . . . . . 71 194 11.3.1. Bounded Latency . . . . . . . . . . . . . . . . . . 71 195 11.3.2. Low Latency . . . . . . . . . . . . . . . . . . . . 72 196 11.3.3. Symmetrical Path Delays . . . . . . . . . . . . . . 72 197 11.4. High Reliability and Availability . . . . . . . . . . . 72 198 11.5. Security . . . . . . . . . . . . . . . . . . . . . . . . 72 199 11.6. Deterministic Flows . . . . . . . . . . . . . . . . . . 73 200 12. Use Cases Explicitly Out of Scope for DetNet . . . . . . . . 73 201 12.1. DetNet Scope Limitations . . . . . . . . . . . . . . . . 73 202 12.2. Internet-based Applications . . . . . . . . . . . . . . 74 203 12.2.1. Use Case Description . . . . . . . . . . . . . . . . 74 204 12.2.1.1. Media Content Delivery . . . . . . . . . . . . . 74 205 12.2.1.2. Online Gaming . . . . . . . . . . . . . . . . . 74 206 12.2.1.3. Virtual Reality . . . . . . . . . . . . . . . . 74 207 12.2.2. Internet-Based Applications Today . . . . . . . . . 74 208 12.2.3. Internet-Based Applications Future . . . . . . . . . 74 209 12.2.4. Internet-Based Applications Asks . . . . . . . . . . 75 210 12.3. Pro Audio and Video - Digital Rights Management (DRM) . 75 211 12.4. Pro Audio and Video - Link Aggregation . . . . . . . . . 75 212 13. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 76 213 14. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 77 214 14.1. Pro Audio . . . . . . . . . . . . . . . . . . . . . . . 77 215 14.2. Utility Telecom . . . . . . . . . . . . . . . . . . . . 78 216 14.3. Building Automation Systems . . . . . . . . . . . . . . 78 217 14.4. Wireless for Industrial . . . . . . . . . . . . . . . . 78 218 14.5. Cellular Radio . . . . . . . . . . . . . . . . . . . . . 78 219 14.6. Industrial M2M . . . . . . . . . . . . . . . . . . . . . 78 220 14.7. Internet Applications and CoMP . . . . . . . . . . . . . 79 221 14.8. Electrical Utilities . . . . . . . . . . . . . . . . . . 79 222 14.9. Network Slicing . . . . . . . . . . . . . . . . . . . . 79 223 14.10. Mining . . . . . . . . . . . . . . . . . . . . . . . . . 79 224 14.11. Private Blockchain . . . . . . . . . . . . . . . . . . . 79 225 15. Informative References . . . . . . . . . . . . . . . . . . . 79 226 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 90 228 1. Introduction 230 This draft presents use cases from diverse industries which have in 231 common a need for deterministic streams, but which also differ 232 notably in their network topologies and specific desired behavior. 233 Together, they provide broad industry context for DetNet and a 234 yardstick against which proposed DetNet designs can be measured (to 235 what extent does a proposed design satisfy these various use cases?) 237 For DetNet, use cases explicitly do not define requirements; The 238 DetNet WG will consider the use cases, decide which elements are in 239 scope for DetNet, and the results will be incorporated into future 240 drafts. Similarly, the DetNet use case draft explicitly does not 241 suggest any specific design, architecture or protocols, which will be 242 topics of future drafts. 244 We present for each use case the answers to the following questions: 246 o What is the use case? 248 o How is it addressed today? 250 o How would you like it to be addressed in the future? 252 o What do you want the IETF to deliver? 254 The level of detail in each use case should be sufficient to express 255 the relevant elements of the use case, but not more. 257 At the end we consider the use cases collectively, and examine the 258 most significant goals they have in common. 260 2. Pro Audio and Video 262 2.1. Use Case Description 264 The professional audio and video industry ("ProAV") includes: 266 o Music and film content creation 268 o Broadcast 270 o Cinema 272 o Live sound 274 o Public address, media and emergency systems at large venues 275 (airports, stadiums, churches, theme parks). 277 These industries have already transitioned audio and video signals 278 from analog to digital. However, the digital interconnect systems 279 remain primarily point-to-point with a single (or small number of) 280 signals per link, interconnected with purpose-built hardware. 282 These industries are now transitioning to packet-based infrastructure 283 to reduce cost, increase routing flexibility, and integrate with 284 existing IT infrastructure. 286 Today ProAV applications have no way to establish deterministic 287 streams from a standards-based Layer 3 (IP) interface, which is a 288 fundamental limitation to the use cases described here. Today 289 deterministic streams can be created within standards-based layer 2 290 LANs (e.g. using IEEE 802.1 AVB) however these are not routable via 291 IP and thus are not effective for distribution over wider areas (for 292 example broadcast events that span wide geographical areas). 294 It would be highly desirable if such streams could be routed over the 295 open Internet, however solutions with more limited scope (e.g. 296 enterprise networks) would still provide a substantial improvement. 298 The following sections describe specific ProAV use cases. 300 2.1.1. Uninterrupted Stream Playback 302 Transmitting audio and video streams for live playback is unlike 303 common file transfer because uninterrupted stream playback in the 304 presence of network errors cannot be achieved by re-trying the 305 transmission; by the time the missing or corrupt packet has been 306 identified it is too late to execute a re-try operation. Buffering 307 can be used to provide enough delay to allow time for one or more 308 retries, however this is not an effective solution in applications 309 where large delays (latencies) are not acceptable (as discussed 310 below). 312 Streams with guaranteed bandwidth can eliminate congestion on the 313 network as a cause of transmission errors that would lead to playback 314 interruption. Use of redundant paths can further mitigate 315 transmission errors to provide greater stream reliability. 317 2.1.2. Synchronized Stream Playback 319 Latency in this context is the time between when a signal is 320 initially sent over a stream and when it is received. A common 321 example in ProAV is time-synchronizing audio and video when they take 322 separate paths through the playback system. In this case the latency 323 of both the audio and video streams must be bounded and consistent if 324 the sound is to remain matched to the movement in the video. A 325 common tolerance for audio/video sync is one NTSC video frame (about 326 33ms) and to maintain the audience perception of correct lip sync the 327 latency needs to be consistent within some reasonable tolerance, for 328 example 10%. 330 A common architecture for synchronizing multiple streams that have 331 different paths through the network (and thus potentially different 332 latencies) is to enable measurement of the latency of each path, and 333 have the data sinks (for example speakers) delay (buffer) all packets 334 on all but the slowest path. Each packet of each stream is assigned 335 a presentation time which is based on the longest required delay. 337 This implies that all sinks must maintain a common time reference of 338 sufficient accuracy, which can be achieved by any of various 339 techniques. 341 This type of architecture is commonly implemented using a central 342 controller that determines path delays and arbitrates buffering 343 delays. 345 2.1.3. Sound Reinforcement 347 Consider the latency (delay) from when a person speaks into a 348 microphone to when their voice emerges from the speaker. If this 349 delay is longer than about 10-15 milliseconds it is noticeable and 350 can make a sound reinforcement system unusable (see slide 6 of 351 [SRP_LATENCY]). (If you have ever tried to speak in the presence of 352 a delayed echo of your voice you may know this experience). 354 Note that the 15ms latency bound includes all parts of the signal 355 path, not just the network, so the network latency must be 356 significantly less than 15ms. 358 In some cases local performers must perform in synchrony with a 359 remote broadcast. In such cases the latencies of the broadcast 360 stream and the local performer must be adjusted to match each other, 361 with a worst case of one video frame (33ms for NTSC video). 363 In cases where audio phase is a consideration, for example beam- 364 forming using multiple speakers, latency requirements can be in the 365 10 microsecond range (1 audio sample at 96kHz). 367 2.1.4. Deterministic Time to Establish Streaming 369 Note: The WG has decided that guidelines for deterministic time to 370 establish stream startup is not within scope of DetNet. If bounded 371 timing of establishing or re-establish streams is required in a given 372 use case, it is up to the application/system to achieve this. (The 373 supporting text from this section has been removed as of draft 12). 375 2.1.5. Secure Transmission 377 2.1.5.1. Safety 379 Professional audio systems can include amplifiers that are capable of 380 generating hundreds or thousands of watts of audio power which if 381 used incorrectly can cause hearing damage to those in the vicinity. 382 Apart from the usual care required by the systems operators to 383 prevent such incidents, the network traffic that controls these 384 devices must be secured (as with any sensitive application traffic). 386 2.2. Pro Audio Today 388 Some proprietary systems have been created which enable deterministic 389 streams at Layer 3 however they are "engineered networks" which 390 require careful configuration to operate, often require that the 391 system be over-provisioned, and it is implied that all devices on the 392 network voluntarily play by the rules of that network. To enable 393 these industries to successfully transition to an interoperable 394 multi-vendor packet-based infrastructure requires effective open 395 standards, and we believe that establishing relevant IETF standards 396 is a crucial factor. 398 2.3. Pro Audio Future 400 2.3.1. Layer 3 Interconnecting Layer 2 Islands 402 It would be valuable to enable IP to connect multiple Layer 2 LANs. 404 As an example, ESPN recently constructed a state-of-the-art 194,000 405 sq ft, $125 million broadcast studio called DC2. The DC2 network is 406 capable of handling 46 Tbps of throughput with 60,000 simultaneous 407 signals. Inside the facility are 1,100 miles of fiber feeding four 408 audio control rooms (see [ESPN_DC2] ). 410 In designing DC2 they replaced as much point-to-point technology as 411 they could with packet-based technology. They constructed seven 412 individual studios using layer 2 LANS (using IEEE 802.1 AVB) that 413 were entirely effective at routing audio within the LANs. However to 414 interconnect these layer 2 LAN islands together they ended up using 415 dedicated paths in a custom SDN (Software Defined Networking) router 416 because there is no standards-based routing solution available. 418 2.3.2. High Reliability Stream Paths 420 On-air and other live media streams are often backed up with 421 redundant links that seamlessly act to deliver the content when the 422 primary link fails for any reason. In point-to-point systems this is 423 provided by an additional point-to-point link; the analogous 424 requirement in a packet-based system is to provide an alternate path 425 through the network such that no individual link can bring down the 426 system. 428 2.3.3. Integration of Reserved Streams into IT Networks 430 A commonly cited goal of moving to a packet based media 431 infrastructure is that costs can be reduced by using off the shelf, 432 commodity network hardware. In addition, economy of scale can be 433 realized by combining media infrastructure with IT infrastructure. 435 In keeping with these goals, stream reservation technology should be 436 compatible with existing protocols, and not compromise use of the 437 network for best effort (non-time-sensitive) traffic. 439 2.3.4. Use of Unused Reservations by Best-Effort Traffic 441 In cases where stream bandwidth is reserved but not currently used 442 (or is under-utilized) that bandwidth must be available to best- 443 effort (i.e. non-time-sensitive) traffic. For example a single 444 stream may be nailed up (reserved) for specific media content that 445 needs to be presented at different times of the day, ensuring timely 446 delivery of that content, yet in between those times the full 447 bandwidth of the network can be utilized for best-effort tasks such 448 as file transfers. 450 This also addresses a concern of IT network administrators that are 451 considering adding reserved bandwidth traffic to their networks that 452 ("users will reserve large quantities of bandwidth and then never un- 453 reserve it even though they are not using it, and soon the network 454 will have no bandwidth left"). 456 2.3.5. Traffic Segregation 458 Note: It is still under WG discussion whether this topic will be 459 addressed by DetNet. 461 Sink devices may be low cost devices with limited processing power. 462 In order to not overwhelm the CPUs in these devices it is important 463 to limit the amount of traffic that these devices must process. 465 As an example, consider the use of individual seat speakers in a 466 cinema. These speakers are typically required to be cost reduced 467 since the quantities in a single theater can reach hundreds of seats. 468 Discovery protocols alone in a one thousand seat theater can generate 469 enough broadcast traffic to overwhelm a low powered CPU. Thus an 470 installation like this will benefit greatly from some type of traffic 471 segregation that can define groups of seats to reduce traffic within 472 each group. All seats in the theater must still be able to 473 communicate with a central controller. 475 There are many techniques that can be used to support this 476 requirement including (but not limited to) the following examples. 478 2.3.5.1. Packet Forwarding Rules, VLANs and Subnets 480 Packet forwarding rules can be used to eliminate some extraneous 481 streaming traffic from reaching potentially low powered sink devices, 482 however there may be other types of broadcast traffic that should be 483 eliminated using other means for example VLANs or IP subnets. 485 2.3.5.2. Multicast Addressing (IPv4 and IPv6) 487 Multicast addressing is commonly used to keep bandwidth utilization 488 of shared links to a minimum. 490 Because of the MAC Address forwarding nature of Layer 2 bridges it is 491 important that a multicast MAC address is only associated with one 492 stream. This will prevent reservations from forwarding packets from 493 one stream down a path that has no interested sinks simply because 494 there is another stream on that same path that shares the same 495 multicast MAC address. 497 Since each multicast MAC Address can represent 32 different IPv4 498 multicast addresses there must be a process put in place to make sure 499 this does not occur. Requiring use of IPv6 address can achieve this, 500 however due to their continued prevalence, solutions that are 501 effective for IPv4 installations are also required. 503 2.3.6. Latency Optimization by a Central Controller 505 A central network controller might also perform optimizations based 506 on the individual path delays, for example sinks that are closer to 507 the source can inform the controller that they can accept greater 508 latency since they will be buffering packets to match presentation 509 times of farther away sinks. The controller might then move a stream 510 reservation on a short path to a longer path in order to free up 511 bandwidth for other critical streams on that short path. See slides 512 3-5 of [SRP_LATENCY]. 514 Additional optimization can be achieved in cases where sinks have 515 differing latency requirements, for example in a live outdoor concert 516 the speaker sinks have stricter latency requirements than the 517 recording hardware sinks. See slide 7 of [SRP_LATENCY]. 519 2.3.7. Reduced Device Cost Due To Reduced Buffer Memory 521 Device cost can be reduced in a system with guaranteed reservations 522 with a small bounded latency due to the reduced requirements for 523 buffering (i.e. memory) on sink devices. For example, a theme park 524 might broadcast a live event across the globe via a layer 3 protocol; 525 in such cases the size of the buffers required is proportional to the 526 latency bounds and jitter caused by delivery, which depends on the 527 worst case segment of the end-to-end network path. For example on 528 todays open internet the latency is typically unacceptable for audio 529 and video streaming without many seconds of buffering. In such 530 scenarios a single gateway device at the local network that receives 531 the feed from the remote site would provide the expensive buffering 532 required to mask the latency and jitter issues associated with long 533 distance delivery. Sink devices in the local location would have no 534 additional buffering requirements, and thus no additional costs, 535 beyond those required for delivery of local content. The sink device 536 would be receiving the identical packets as those sent by the source 537 and would be unaware that there were any latency or jitter issues 538 along the path. 540 2.4. Pro Audio Asks 542 o Layer 3 routing on top of AVB (and/or other high QoS networks) 544 o Content delivery with bounded, lowest possible latency 546 o IntServ and DiffServ integration with AVB (where practical) 548 o Single network for A/V and IT traffic 550 o Standards-based, interoperable, multi-vendor 552 o IT department friendly 554 o Enterprise-wide networks (e.g. size of San Francisco but not the 555 whole Internet (yet...)) 557 3. Electrical Utilities 559 3.1. Use Case Description 561 Many systems that an electrical utility deploys today rely on high 562 availability and deterministic behavior of the underlying networks. 563 Here we present use cases in Transmission, Generation and 564 Distribution, including key timing and reliability metrics. We also 565 discuss security issues and industry trends which affect the 566 architecture of next generation utility networks 568 3.1.1. Transmission Use Cases 570 3.1.1.1. Protection 572 Protection means not only the protection of human operators but also 573 the protection of the electrical equipment and the preservation of 574 the stability and frequency of the grid. If a fault occurs in the 575 transmission or distribution of electricity then severe damage can 576 occur to human operators, electrical equipment and the grid itself, 577 leading to blackouts. 579 Communication links in conjunction with protection relays are used to 580 selectively isolate faults on high voltage lines, transformers, 581 reactors and other important electrical equipment. The role of the 582 teleprotection system is to selectively disconnect a faulty part by 583 transferring command signals within the shortest possible time. 585 3.1.1.1.1. Key Criteria 587 The key criteria for measuring teleprotection performance are command 588 transmission time, dependability and security. These criteria are 589 defined by the IEC standard 60834 as follows: 591 o Transmission time (Speed): The time between the moment where state 592 changes at the transmitter input and the moment of the 593 corresponding change at the receiver output, including propagation 594 delay. Overall operating time for a teleprotection system 595 includes the time for initiating the command at the transmitting 596 end, the propagation delay over the network (including equipments) 597 and the selection and decision time at the receiving end, 598 including any additional delay due to a noisy environment. 600 o Dependability: The ability to issue and receive valid commands in 601 the presence of interference and/or noise, by minimizing the 602 probability of missing command (PMC). Dependability targets are 603 typically set for a specific bit error rate (BER) level. 605 o Security: The ability to prevent false tripping due to a noisy 606 environment, by minimizing the probability of unwanted commands 607 (PUC). Security targets are also set for a specific bit error 608 rate (BER) level. 610 Additional elements of the the teleprotection system that impact its 611 performance include: 613 o Network bandwidth 615 o Failure recovery capacity (aka resiliency) 617 3.1.1.1.2. Fault Detection and Clearance Timing 619 Most power line equipment can tolerate short circuits or faults for 620 up to approximately five power cycles before sustaining irreversible 621 damage or affecting other segments in the network. This translates 622 to total fault clearance time of 100ms. As a safety precaution, 623 however, actual operation time of protection systems is limited to 624 70- 80 percent of this period, including fault recognition time, 625 command transmission time and line breaker switching time. 627 Some system components, such as large electromechanical switches, 628 require particularly long time to operate and take up the majority of 629 the total clearance time, leaving only a 10ms window for the 630 telecommunications part of the protection scheme, independent of the 631 distance to travel. Given the sensitivity of the issue, new networks 632 impose requirements that are even more stringent: IEC standard 61850 633 limits the transfer time for protection messages to 1/4 - 1/2 cycle 634 or 4 - 8ms (for 60Hz lines) for the most critical messages. 636 3.1.1.1.3. Symmetric Channel Delay 638 Note: It is currently under WG discussion whether symmetric path 639 delays are to be guaranteed by DetNet. 641 Teleprotection channels which are differential must be synchronous, 642 which means that any delays on the transmit and receive paths must 643 match each other. Teleprotection systems ideally support zero 644 asymmetric delay; typical legacy relays can tolerate delay 645 discrepancies of up to 750us. 647 Some tools available for lowering delay variation below this 648 threshold are: 650 o For legacy systems using Time Division Multiplexing (TDM), jitter 651 buffers at the multiplexers on each end of the line can be used to 652 offset delay variation by queuing sent and received packets. The 653 length of the queues must balance the need to regulate the rate of 654 transmission with the need to limit overall delay, as larger 655 buffers result in increased latency. 657 o For jitter-prone IP packet networks, traffic management tools can 658 ensure that the teleprotection signals receive the highest 659 transmission priority to minimize jitter. 661 o Standard packet-based synchronization technologies, such as 662 1588-2008 Precision Time Protocol (PTP) and Synchronous Ethernet 663 (Sync-E), can help keep networks stable by maintaining a highly 664 accurate clock source on the various network devices. 666 3.1.1.1.4. Teleprotection Network Requirements (IEC 61850) 668 The following table captures the main network metrics as based on the 669 IEC 61850 standard. 671 +-----------------------------+-------------------------------------+ 672 | Teleprotection Requirement | Attribute | 673 +-----------------------------+-------------------------------------+ 674 | One way maximum delay | 4-10 ms | 675 | Asymetric delay required | Yes | 676 | Maximum jitter | less than 250 us (750 us for legacy | 677 | | IED) | 678 | Topology | Point to point, point to Multi- | 679 | | point | 680 | Availability | 99.9999 | 681 | precise timing required | Yes | 682 | Recovery time on node | less than 50ms - hitless | 683 | failure | | 684 | performance management | Yes, Mandatory | 685 | Redundancy | Yes | 686 | Packet loss | 0.1% to 1% | 687 +-----------------------------+-------------------------------------+ 689 Table 1: Teleprotection network requirements 691 3.1.1.1.5. Inter-Trip Protection scheme 693 "Inter-tripping" is the signal-controlled tripping of a circuit 694 breaker to complete the isolation of a circuit or piece of apparatus 695 in concert with the tripping of other circuit breakers. 697 +--------------------------------+----------------------------------+ 698 | Inter-Trip protection | Attribute | 699 | Requirement | | 700 +--------------------------------+----------------------------------+ 701 | One way maximum delay | 5 ms | 702 | Asymetric delay required | No | 703 | Maximum jitter | Not critical | 704 | Topology | Point to point, point to Multi- | 705 | | point | 706 | Bandwidth | 64 Kbps | 707 | Availability | 99.9999 | 708 | precise timing required | Yes | 709 | Recovery time on node failure | less than 50ms - hitless | 710 | performance management | Yes, Mandatory | 711 | Redundancy | Yes | 712 | Packet loss | 0.1% | 713 +--------------------------------+----------------------------------+ 715 Table 2: Inter-Trip protection network requirements 717 3.1.1.1.6. Current Differential Protection Scheme 719 Current differential protection is commonly used for line protection, 720 and is typical for protecting parallel circuits. At both end of the 721 lines the current is measured by the differential relays, and both 722 relays will trip the circuit breaker if the current going into the 723 line does not equal the current going out of the line. This type of 724 protection scheme assumes some form of communications being present 725 between the relays at both end of the line, to allow both relays to 726 compare measured current values. Line differential protection 727 schemes assume a very low telecommunications delay between both 728 relays, often as low as 5ms. Moreover, as those systems are often 729 not time-synchronized, they also assume symmetric telecommunications 730 paths with constant delay, which allows comparing current measurement 731 values taken at the exact same time. 733 +----------------------------------+--------------------------------+ 734 | Current Differential protection | Attribute | 735 | Requirement | | 736 +----------------------------------+--------------------------------+ 737 | One way maximum delay | 5 ms | 738 | Asymetric delay Required | Yes | 739 | Maximum jitter | less than 250 us (750us for | 740 | | legacy IED) | 741 | Topology | Point to point, point to | 742 | | Multi-point | 743 | Bandwidth | 64 Kbps | 744 | Availability | 99.9999 | 745 | precise timing required | Yes | 746 | Recovery time on node failure | less than 50ms - hitless | 747 | performance management | Yes, Mandatory | 748 | Redundancy | Yes | 749 | Packet loss | 0.1% | 750 +----------------------------------+--------------------------------+ 752 Table 3: Current Differential Protection metrics 754 3.1.1.1.7. Distance Protection Scheme 756 Distance (Impedance Relay) protection scheme is based on voltage and 757 current measurements. The network metrics are similar (but not 758 identical to) Current Differential protection. 760 +-------------------------------+-----------------------------------+ 761 | Distance protection | Attribute | 762 | Requirement | | 763 +-------------------------------+-----------------------------------+ 764 | One way maximum delay | 5 ms | 765 | Asymetric delay Required | No | 766 | Maximum jitter | Not critical | 767 | Topology | Point to point, point to Multi- | 768 | | point | 769 | Bandwidth | 64 Kbps | 770 | Availability | 99.9999 | 771 | precise timing required | Yes | 772 | Recovery time on node failure | less than 50ms - hitless | 773 | performance management | Yes, Mandatory | 774 | Redundancy | Yes | 775 | Packet loss | 0.1% | 776 +-------------------------------+-----------------------------------+ 778 Table 4: Distance Protection requirements 780 3.1.1.1.8. Inter-Substation Protection Signaling 782 This use case describes the exchange of Sampled Value and/or GOOSE 783 (Generic Object Oriented Substation Events) message between 784 Intelligent Electronic Devices (IED) in two substations for 785 protection and tripping coordination. The two IEDs are in a master- 786 slave mode. 788 The Current Transformer or Voltage Transformer (CT/VT) in one 789 substation sends the sampled analog voltage or current value to the 790 Merging Unit (MU) over hard wire. The MU sends the time-synchronized 791 61850-9-2 sampled values to the slave IED. The slave IED forwards 792 the information to the Master IED in the other substation. The 793 master IED makes the determination (for example based on sampled 794 value differentials) to send a trip command to the originating IED. 795 Once the slave IED/Relay receives the GOOSE trip for breaker 796 tripping, it opens the breaker. It then sends a confirmation message 797 back to the master. All data exchanges between IEDs are either 798 through Sampled Value and/or GOOSE messages. 800 +----------------------------------+--------------------------------+ 801 | Inter-Substation protection | Attribute | 802 | Requirement | | 803 +----------------------------------+--------------------------------+ 804 | One way maximum delay | 5 ms | 805 | Asymetric delay Required | No | 806 | Maximum jitter | Not critical | 807 | Topology | Point to point, point to | 808 | | Multi-point | 809 | Bandwidth | 64 Kbps | 810 | Availability | 99.9999 | 811 | precise timing required | Yes | 812 | Recovery time on node failure | less than 50ms - hitless | 813 | performance management | Yes, Mandatory | 814 | Redundancy | Yes | 815 | Packet loss | 1% | 816 +----------------------------------+--------------------------------+ 818 Table 5: Inter-Substation Protection requirements 820 3.1.1.2. Intra-Substation Process Bus Communications 822 This use case describes the data flow from the CT/VT to the IEDs in 823 the substation via the MU. The CT/VT in the substation send the 824 analog voltage or current values to the MU over hard wire. The MU 825 converts the analog values into digital format (typically time- 826 synchronized Sampled Values as specified by IEC 61850-9-2) and sends 827 them to the IEDs in the substation. The GPS Master Clock can send 828 1PPS or IRIG-B format to the MU through a serial port or IEEE 1588 829 protocol via a network. Process bus communication using 61850 830 simplifies connectivity within the substation and removes the 831 requirement for multiple serial connections and removes the slow 832 serial bus architectures that are typically used. This also ensures 833 increased flexibility and increased speed with the use of multicast 834 messaging between multiple devices. 836 +----------------------------------+--------------------------------+ 837 | Intra-Substation protection | Attribute | 838 | Requirement | | 839 +----------------------------------+--------------------------------+ 840 | One way maximum delay | 5 ms | 841 | Asymetric delay Required | No | 842 | Maximum jitter | Not critical | 843 | Topology | Point to point, point to | 844 | | Multi-point | 845 | Bandwidth | 64 Kbps | 846 | Availability | 99.9999 | 847 | precise timing required | Yes | 848 | Recovery time on Node failure | less than 50ms - hitless | 849 | performance management | Yes, Mandatory | 850 | Redundancy | Yes - No | 851 | Packet loss | 0.1% | 852 +----------------------------------+--------------------------------+ 854 Table 6: Intra-Substation Protection requirements 856 3.1.1.3. Wide Area Monitoring and Control Systems 858 The application of synchrophasor measurement data from Phasor 859 Measurement Units (PMU) to Wide Area Monitoring and Control Systems 860 promises to provide important new capabilities for improving system 861 stability. Access to PMU data enables more timely situational 862 awareness over larger portions of the grid than what has been 863 possible historically with normal SCADA (Supervisory Control and Data 864 Acquisition) data. Handling the volume and real-time nature of 865 synchrophasor data presents unique challenges for existing 866 application architectures. Wide Area management System (WAMS) makes 867 it possible for the condition of the bulk power system to be observed 868 and understood in real-time so that protective, preventative, or 869 corrective action can be taken. Because of the very high sampling 870 rate of measurements and the strict requirement for time 871 synchronization of the samples, WAMS has stringent telecommunications 872 requirements in an IP network that are captured in the following 873 table: 875 +----------------------+--------------------------------------------+ 876 | WAMS Requirement | Attribute | 877 +----------------------+--------------------------------------------+ 878 | One way maximum | 50 ms | 879 | delay | | 880 | Asymetric delay | No | 881 | Required | | 882 | Maximum jitter | Not critical | 883 | Topology | Point to point, point to Multi-point, | 884 | | Multi-point to Multi-point | 885 | Bandwidth | 100 Kbps | 886 | Availability | 99.9999 | 887 | precise timing | Yes | 888 | required | | 889 | Recovery time on | less than 50ms - hitless | 890 | Node failure | | 891 | performance | Yes, Mandatory | 892 | management | | 893 | Redundancy | Yes | 894 | Packet loss | 1% | 895 | Consecutive Packet | At least 1 packet per application cycle | 896 | Loss | must be received. | 897 +----------------------+--------------------------------------------+ 899 Table 7: WAMS Special Communication Requirements 901 3.1.1.4. IEC 61850 WAN engineering guidelines requirement 902 classification 904 The IEC (International Electrotechnical Commission) has recently 905 published a Technical Report which offers guidelines on how to define 906 and deploy Wide Area Networks for the interconnections of electric 907 substations, generation plants and SCADA operation centers. The IEC 908 61850-90-12 is providing a classification of WAN communication 909 requirements into 4 classes. Table 8 summarizes these requirements: 911 +----------------+------------+------------+------------+-----------+ 912 | WAN | Class WA | Class WB | Class WC | Class WD | 913 | Requirement | | | | | 914 +----------------+------------+------------+------------+-----------+ 915 | Application | EHV (Extra | HV (High | MV (Medium | General | 916 | field | High | Voltage) | Voltage) | purpose | 917 | | Voltage) | | | | 918 | Latency | 5 ms | 10 ms | 100 ms | > 100 ms | 919 | Jitter | 10 us | 100 us | 1 ms | 10 ms | 920 | Latency | 100 us | 1 ms | 10 ms | 100 ms | 921 | Asymetry | | | | | 922 | Time Accuracy | 1 us | 10 us | 100 us | 10 to 100 | 923 | | | | | ms | 924 | Bit Error rate | 10-7 to | 10-5 to | 10-3 | | 925 | | 10-6 | 10-4 | | | 926 | Unavailability | 10-7 to | 10-5 to | 10-3 | | 927 | | 10-6 | 10-4 | | | 928 | Recovery delay | Zero | 50 ms | 5 s | 50 s | 929 | Cyber security | extremely | High | Medium | Medium | 930 | | high | | | | 931 +----------------+------------+------------+------------+-----------+ 933 Table 8: 61850-90-12 Communication Requirements; Courtesy of IEC 935 3.1.2. Generation Use Case 937 Energy generation systems are complex infrastructures that require 938 control of both the generated power and the generation 939 infrastructure. 941 3.1.2.1. Control of the Generated Power 943 The electrical power generation frequency must be maintained within a 944 very narrow band. Deviations from the acceptable frequency range are 945 detected and the required signals are sent to the power plants for 946 frequency regulation. 948 Automatic Generation Control (AGC) is a system for adjusting the 949 power output of generators at different power plants, in response to 950 changes in the load. 952 +---------------------------------------------------+---------------+ 953 | FCAG (Frequency Control Automatic Generation) | Attribute | 954 | Requirement | | 955 +---------------------------------------------------+---------------+ 956 | One way maximum delay | 500 ms | 957 | Asymetric delay Required | No | 958 | Maximum jitter | Not critical | 959 | Topology | Point to | 960 | | point | 961 | Bandwidth | 20 Kbps | 962 | Availability | 99.999 | 963 | precise timing required | Yes | 964 | Recovery time on Node failure | N/A | 965 | performance management | Yes, | 966 | | Mandatory | 967 | Redundancy | Yes | 968 | Packet loss | 1% | 969 +---------------------------------------------------+---------------+ 971 Table 9: FCAG Communication Requirements 973 3.1.2.2. Control of the Generation Infrastructure 975 The control of the generation infrastructure combines requirements 976 from industrial automation systems and energy generation systems. In 977 this section we present the use case of the control of the generation 978 infrastructure of a wind turbine. 980 | 981 | 982 | +-----------------+ 983 | | +----+ | 984 | | |WTRM| WGEN | 985 WROT x==|===| | | 986 | | +----+ WCNV| 987 | |WNAC | 988 | +---+---WYAW---+--+ 989 | | | 990 | | | +----+ 991 |WTRF | |WMET| 992 | | | | 993 Wind Turbine | +--+-+ 994 Controller | | 995 WTUR | | | 996 WREP | | | 997 WSLG | | | 998 WALG | WTOW | | 1000 Figure 1: Wind Turbine Control Network 1002 Figure 1 presents the subsystems that operate a wind turbine. These 1003 subsystems include 1005 o WROT (Rotor Control) 1007 o WNAC (Nacelle Control) (nacelle: housing containing the generator) 1009 o WTRM (Transmission Control) 1011 o WGEN (Generator) 1013 o WYAW (Yaw Controller) (of the tower head) 1015 o WCNV (In-Turbine Power Converter) 1017 o WMET (External Meteorological Station providing real time 1018 information to the controllers of the tower) 1020 Traffic characteristics relevant for the network planning and 1021 dimensioning process in a wind turbine scenario are listed below. 1022 The values in this section are based mainly on the relevant 1023 references [Ahm14] and [Spe09]. Each logical node (Figure 1) is a 1024 part of the metering network and produces analog measurements and 1025 status information which must comply with their respective data rate 1026 constraints. 1028 +-----------+--------+--------+-------------+---------+-------------+ 1029 | Subsystem | Sensor | Analog | Data Rate | Status | Data rate | 1030 | | Count | Sample | (bytes/sec) | Sample | (bytes/sec) | 1031 | | | Count | | Count | | 1032 +-----------+--------+--------+-------------+---------+-------------+ 1033 | WROT | 14 | 9 | 642 | 5 | 10 | 1034 | WTRM | 18 | 10 | 2828 | 8 | 16 | 1035 | WGEN | 14 | 12 | 73764 | 2 | 4 | 1036 | WCNV | 14 | 12 | 74060 | 2 | 4 | 1037 | WTRF | 12 | 5 | 73740 | 2 | 4 | 1038 | WNAC | 12 | 9 | 112 | 3 | 6 | 1039 | WYAW | 7 | 8 | 220 | 4 | 8 | 1040 | WTOW | 4 | 1 | 8 | 3 | 6 | 1041 | WMET | 7 | 7 | 228 | - | - | 1042 +-----------+--------+--------+-------------+---------+-------------+ 1044 Table 10: Wind Turbine Data Rate Constraints 1046 Quality of Service (QoS) constraints for different services are 1047 presented in Table 11. These constraints are defined by IEEE 1646 1048 standard [IEEE1646] and IEC 61400 standard [IEC61400]. 1050 +---------------------+---------+-------------+---------------------+ 1051 | Service | Latency | Reliability | Packet Loss Rate | 1052 +---------------------+---------+-------------+---------------------+ 1053 | Analogue measure | 16 ms | 99.99% | < 10-6 | 1054 | Status information | 16 ms | 99.99% | < 10-6 | 1055 | Protection traffic | 4 ms | 100.00% | < 10-9 | 1056 | Reporting and | 1 s | 99.99% | < 10-6 | 1057 | logging | | | | 1058 | Video surveillance | 1 s | 99.00% | No specific | 1059 | | | | requirement | 1060 | Internet connection | 60 min | 99.00% | No specific | 1061 | | | | requirement | 1062 | Control traffic | 16 ms | 100.00% | < 10-9 | 1063 | Data polling | 16 ms | 99.99% | < 10-6 | 1064 +---------------------+---------+-------------+---------------------+ 1066 Table 11: Wind Turbine Reliability and Latency Constraints 1068 3.1.2.2.1. Intra-Domain Network Considerations 1070 A wind turbine is composed of a large set of subsystems including 1071 sensors and actuators which require time-critical operation. The 1072 reliability and latency constraints of these different subsystems is 1073 shown in Table 11. These subsystems are connected to an intra-domain 1074 network which is used to monitor and control the operation of the 1075 turbine and connect it to the SCADA subsystems. The different 1076 components are interconnected using fiber optics, industrial buses, 1077 industrial Ethernet, EtherCat, or a combination of them. Industrial 1078 signaling and control protocols such as Modbus, Profibus, Profinet 1079 and EtherCat are used directly on top of the Layer 2 transport or 1080 encapsulated over TCP/IP. 1082 The Data collected from the sensors and condition monitoring systems 1083 is multiplexed onto fiber cables for transmission to the base of the 1084 tower, and to remote control centers. The turbine controller 1085 continuously monitors the condition of the wind turbine and collects 1086 statistics on its operation. This controller also manages a large 1087 number of switches, hydraulic pumps, valves, and motors within the 1088 wind turbine. 1090 There is usually a controller both at the bottom of the tower and in 1091 the nacelle. The communication between these two controllers usually 1092 takes place using fiber optics instead of copper links. Sometimes, a 1093 third controller is installed in the hub of the rotor and manages the 1094 pitch of the blades. That unit usually communicates with the nacelle 1095 unit using serial communications. 1097 3.1.2.2.2. Inter-Domain network considerations 1099 A remote control center belonging to a grid operator regulates the 1100 power output, enables remote actuation, and monitors the health of 1101 one or more wind parks in tandem. It connects to the local control 1102 center in a wind park over the Internet (Figure 2) via firewalls at 1103 both ends. The AS path between the local control center and the Wind 1104 Park typically involves several ISPs at different tiers. For 1105 example, a remote control center in Denmark can regulate a wind park 1106 in Greece over the normal public AS path between the two locations. 1108 The remote control center is part of the SCADA system, setting the 1109 desired power output to the wind park and reading back the result 1110 once the new power output level has been set. Traffic between the 1111 remote control center and the wind park typically consists of 1112 protocols like IEC 60870-5-104 [IEC-60870-5-104], OPC XML-DA 1113 [OPCXML], Modbus [MODBUS], and SNMP [RFC3411]. Currently, traffic 1114 flows between the wind farm and the remote control center are best 1115 effort. QoS requirements are not strict, so no SLAs or service 1116 provisioning mechanisms (e.g., VPN) are employed. In case of events 1117 like equipment failure, tolerance for alarm delay is on the order of 1118 minutes, due to redundant systems already in place. 1120 +--------------+ 1121 | | 1122 | | 1123 | Wind Park #1 +----+ 1124 | | | XXXXXX 1125 | | | X XXXXXXXX +----------------+ 1126 +--------------+ | XXXX X XXXXX | | 1127 +---+ XXX | Remote Control | 1128 XXX Internet +----+ Center | 1129 +----+X XXX | | 1130 +--------------+ | XXXXXXX XX | | 1131 | | | XX XXXXXXX +----------------+ 1132 | | | XXXXX 1133 | Wind Park #2 +----+ 1134 | | 1135 | | 1136 +--------------+ 1138 Figure 2: Wind Turbine Control via Internet 1140 We expect future use cases which require bounded latency, bounded 1141 jitter and extraordinary low packet loss for inter-domain traffic 1142 flows due to the softwarization and virtualization of core wind farm 1143 equipment (e.g. switches, firewalls and SCADA server components). 1144 These factors will create opportunities for service providers to 1145 install new services and dynamically manage them from remote 1146 locations. For example, to enable fail-over of a local SCADA server, 1147 a SCADA server in another wind farm site (under the administrative 1148 control of the same operator) could be utilized temporarily 1149 (Figure 3). In that case local traffic would be forwarded to the 1150 remote SCADA server and existing intra-domain QoS and timing 1151 parameters would have to be met for inter-domain traffic flows. 1153 +--------------+ 1154 | | 1155 | | 1156 | Wind Park #1 +----+ 1157 | | | XXXXXX 1158 | | | X XXXXXXXX +----------------+ 1159 +--------------+ | XXXX XXXXX | | 1160 +---+ Operator XXX | Remote Control | 1161 XXX Administered +----+ Center | 1162 +----+X WAN XXX | | 1163 +--------------+ | XXXXXXX XX | | 1164 | | | XX XXXXXXX +----------------+ 1165 | | | XXXXX 1166 | Wind Park #2 +----+ 1167 | | 1168 | | 1169 +--------------+ 1171 Figure 3: Wind Turbine Control via Operator Administered WAN 1173 3.1.3. Distribution use case 1175 3.1.3.1. Fault Location Isolation and Service Restoration (FLISR) 1177 Fault Location, Isolation, and Service Restoration (FLISR) refers to 1178 the ability to automatically locate the fault, isolate the fault, and 1179 restore service in the distribution network. This will likely be the 1180 first widespread application of distributed intelligence in the grid. 1182 Static power switch status (open/closed) in the network dictates the 1183 power flow to secondary substations. Reconfiguring the network in 1184 the event of a fault is typically done manually on site to energize/ 1185 de-energize alternate paths. Automating the operation of substation 1186 switchgear allows the flow of power to be altered automatically under 1187 fault conditions. 1189 FLISR can be managed centrally from a Distribution Management System 1190 (DMS) or executed locally through distributed control via intelligent 1191 switches and fault sensors. 1193 +----------------------+--------------------------------------------+ 1194 | FLISR Requirement | Attribute | 1195 +----------------------+--------------------------------------------+ 1196 | One way maximum | 80 ms | 1197 | delay | | 1198 | Asymetric delay | No | 1199 | Required | | 1200 | Maximum jitter | 40 ms | 1201 | Topology | Point to point, point to Multi-point, | 1202 | | Multi-point to Multi-point | 1203 | Bandwidth | 64 Kbps | 1204 | Availability | 99.9999 | 1205 | precise timing | Yes | 1206 | required | | 1207 | Recovery time on | Depends on customer impact | 1208 | Node failure | | 1209 | performance | Yes, Mandatory | 1210 | management | | 1211 | Redundancy | Yes | 1212 | Packet loss | 0.1% | 1213 +----------------------+--------------------------------------------+ 1215 Table 12: FLISR Communication Requirements 1217 3.2. Electrical Utilities Today 1219 Many utilities still rely on complex environments formed of multiple 1220 application-specific proprietary networks, including TDM networks. 1222 In this kind of environment there is no mixing of OT and IT 1223 applications on the same network, and information is siloed between 1224 operational areas. 1226 Specific calibration of the full chain is required, which is costly. 1228 This kind of environment prevents utility operations from realizing 1229 the operational efficiency benefits, visibility, and functional 1230 integration of operational information across grid applications and 1231 data networks. 1233 In addition, there are many security-related issues as discussed in 1234 the following section. 1236 3.2.1. Security Current Practices and Limitations 1238 Grid monitoring and control devices are already targets for cyber 1239 attacks, and legacy telecommunications protocols have many intrinsic 1240 network-related vulnerabilities. For example, DNP3, Modbus, 1241 PROFIBUS/PROFINET, and other protocols are designed around a common 1242 paradigm of request and respond. Each protocol is designed for a 1243 master device such as an HMI (Human Machine Interface) system to send 1244 commands to subordinate slave devices to retrieve data (reading 1245 inputs) or control (writing to outputs). Because many of these 1246 protocols lack authentication, encryption, or other basic security 1247 measures, they are prone to network-based attacks, allowing a 1248 malicious actor or attacker to utilize the request-and-respond system 1249 as a mechanism for command-and-control like functionality. Specific 1250 security concerns common to most industrial control, including 1251 utility telecommunication protocols include the following: 1253 o Network or transport errors (e.g. malformed packets or excessive 1254 latency) can cause protocol failure. 1256 o Protocol commands may be available that are capable of forcing 1257 slave devices into inoperable states, including powering-off 1258 devices, forcing them into a listen-only state, disabling 1259 alarming. 1261 o Protocol commands may be available that are capable of restarting 1262 communications and otherwise interrupting processes. 1264 o Protocol commands may be available that are capable of clearing, 1265 erasing, or resetting diagnostic information such as counters and 1266 diagnostic registers. 1268 o Protocol commands may be available that are capable of requesting 1269 sensitive information about the controllers, their configurations, 1270 or other need-to-know information. 1272 o Most protocols are application layer protocols transported over 1273 TCP; therefore it is easy to transport commands over non-standard 1274 ports or inject commands into authorized traffic flows. 1276 o Protocol commands may be available that are capable of 1277 broadcasting messages to many devices at once (i.e. a potential 1278 DoS). 1280 o Protocol commands may be available to query the device network to 1281 obtain defined points and their values (i.e. a configuration 1282 scan). 1284 o Protocol commands may be available that will list all available 1285 function codes (i.e. a function scan). 1287 These inherent vulnerabilities, along with increasing connectivity 1288 between IT an OT networks, make network-based attacks very feasible. 1290 Simple injection of malicious protocol commands provides control over 1291 the target process. Altering legitimate protocol traffic can also 1292 alter information about a process and disrupt the legitimate controls 1293 that are in place over that process. A man-in-the-middle attack 1294 could provide both control over a process and misrepresentation of 1295 data back to operator consoles. 1297 3.3. Electrical Utilities Future 1299 The business and technology trends that are sweeping the utility 1300 industry will drastically transform the utility business from the way 1301 it has been for many decades. At the core of many of these changes 1302 is a drive to modernize the electrical grid with an integrated 1303 telecommunications infrastructure. However, interoperability 1304 concerns, legacy networks, disparate tools, and stringent security 1305 requirements all add complexity to the grid transformation. Given 1306 the range and diversity of the requirements that should be addressed 1307 by the next generation telecommunications infrastructure, utilities 1308 need to adopt a holistic architectural approach to integrate the 1309 electrical grid with digital telecommunications across the entire 1310 power delivery chain. 1312 The key to modernizing grid telecommunications is to provide a 1313 common, adaptable, multi-service network infrastructure for the 1314 entire utility organization. Such a network serves as the platform 1315 for current capabilities while enabling future expansion of the 1316 network to accommodate new applications and services. 1318 To meet this diverse set of requirements, both today and in the 1319 future, the next generation utility telecommunnications network will 1320 be based on open-standards-based IP architecture. An end-to-end IP 1321 architecture takes advantage of nearly three decades of IP technology 1322 development, facilitating interoperability and device management 1323 across disparate networks and devices, as it has been already 1324 demonstrated in many mission-critical and highly secure networks. 1326 IPv6 is seen as a future telecommunications technology for the Smart 1327 Grid; the IEC (International Electrotechnical Commission) and 1328 different National Committees have mandated a specific adhoc group 1329 (AHG8) to define the migration strategy to IPv6 for all the IEC TC57 1330 power automation standards. The AHG8 has recently finalised the work 1331 on the migration strategy and the following Technical Report has been 1332 issued: IEC TR 62357-200:2015: Guidelines for migration from Internet 1333 Protocol version 4 (IPv4) to Internet Protocol version 6 (IPv6). 1335 We expect cloud-based SCADA systems to control and monitor the 1336 critical and non-critical subsystems of generation systems, for 1337 example wind farms. 1339 3.3.1. Migration to Packet-Switched Network 1341 Throughout the world, utilities are increasingly planning for a 1342 future based on smart grid applications requiring advanced 1343 telecommunications systems. Many of these applications utilize 1344 packet connectivity for communicating information and control signals 1345 across the utility's Wide Area Network (WAN), made possible by 1346 technologies such as multiprotocol label switching (MPLS). The data 1347 that traverses the utility WAN includes: 1349 o Grid monitoring, control, and protection data 1351 o Non-control grid data (e.g. asset data for condition-based 1352 monitoring) 1354 o Physical safety and security data (e.g. voice and video) 1356 o Remote worker access to corporate applications (voice, maps, 1357 schematics, etc.) 1359 o Field area network backhaul for smart metering, and distribution 1360 grid management 1362 o Enterprise traffic (email, collaboration tools, business 1363 applications) 1365 WANs support this wide variety of traffic to and from substations, 1366 the transmission and distribution grid, generation sites, between 1367 control centers, and between work locations and data centers. To 1368 maintain this rapidly expanding set of applications, many utilities 1369 are taking steps to evolve present time-division multiplexing (TDM) 1370 based and frame relay infrastructures to packet systems. Packet- 1371 based networks are designed to provide greater functionalities and 1372 higher levels of service for applications, while continuing to 1373 deliver reliability and deterministic (real-time) traffic support. 1375 3.3.2. Telecommunications Trends 1377 These general telecommunications topics are in addition to the use 1378 cases that have been addressed so far. These include both current 1379 and future telecommunications related topics that should be factored 1380 into the network architecture and design. 1382 3.3.2.1. General Telecommunications Requirements 1384 o IP Connectivity everywhere 1386 o Monitoring services everywhere and from different remote centers 1387 o Move services to a virtual data center 1389 o Unify access to applications / information from the corporate 1390 network 1392 o Unify services 1394 o Unified Communications Solutions 1396 o Mix of fiber and microwave technologies - obsolescence of SONET/ 1397 SDH or TDM 1399 o Standardize grid telecommunications protocol to opened standard to 1400 ensure interoperability 1402 o Reliable Telecommunications for Transmission and Distribution 1403 Substations 1405 o IEEE 1588 time synchronization Client / Server Capabilities 1407 o Integration of Multicast Design 1409 o QoS Requirements Mapping 1411 o Enable Future Network Expansion 1413 o Substation Network Resilience 1415 o Fast Convergence Design 1417 o Scalable Headend Design 1419 o Define Service Level Agreements (SLA) and Enable SLA Monitoring 1421 o Integration of 3G/4G Technologies and future technologies 1423 o Ethernet Connectivity for Station Bus Architecture 1425 o Ethernet Connectivity for Process Bus Architecture 1427 o Protection, teleprotection and PMU (Phaser Measurement Unit) on IP 1429 3.3.2.2. Specific Network topologies of Smart Grid Applications 1431 Utilities often have very large private telecommunications networks. 1432 It covers an entire territory / country. The main purpose of the 1433 network, until now, has been to support transmission network 1434 monitoring, control, and automation, remote control of generation 1435 sites, and providing FCAPS (Fault, Configuration, Accounting, 1436 Performance, Security) services from centralized network operation 1437 centers. 1439 Going forward, one network will support operation and maintenance of 1440 electrical networks (generation, transmission, and distribution), 1441 voice and data services for ten of thousands of employees and for 1442 exchange with neighboring interconnections, and administrative 1443 services. To meet those requirements, utility may deploy several 1444 physical networks leveraging different technologies across the 1445 country: an optical network and a microwave network for instance. 1446 Each protection and automatism system between two points has two 1447 telecommunications circuits, one on each network. Path diversity 1448 between two substations is key. Regardless of the event type 1449 (hurricane, ice storm, etc.), one path shall stay available so the 1450 system can still operate. 1452 In the optical network, signals are transmitted over more than tens 1453 of thousands of circuits using fiber optic links, microwave and 1454 telephone cables. This network is the nervous system of the 1455 utility's power transmission operations. The optical network 1456 represents ten of thousands of km of cable deployed along the power 1457 lines, with individual runs as long as 280 km. 1459 3.3.2.3. Precision Time Protocol 1461 Some utilities do not use GPS clocks in generation substations. One 1462 of the main reasons is that some of the generation plants are 30 to 1463 50 meters deep under ground and the GPS signal can be weak and 1464 unreliable. Instead, atomic clocks are used. Clocks are 1465 synchronized amongst each other. Rubidium clocks provide clock and 1466 1ms timestamps for IRIG-B. 1468 Some companies plan to transition to the Precision Time Protocol 1469 (PTP, [IEEE1588]), distributing the synchronization signal over the 1470 IP/MPLS network. PTP provides a mechanism for synchronizing the 1471 clocks of participating nodes to a high degree of accuracy and 1472 precision. 1474 PTP operates based on the following assumptions: 1476 It is assumed that the network eliminates cyclic forwarding of PTP 1477 messages within each communication path (e.g. by using a spanning 1478 tree protocol). 1480 PTP is tolerant of an occasional missed message, duplicated 1481 message, or message that arrived out of order. However, PTP 1482 assumes that such impairments are relatively rare. 1484 PTP was designed assuming a multicast communication model, however 1485 PTP also supports a unicast communication model as long as the 1486 behavior of the protocol is preserved. 1488 Like all message-based time transfer protocols, PTP time accuracy 1489 is degraded by delay asymmetry in the paths taken by event 1490 messages. Asymmetry is not detectable by PTP, however, if such 1491 delays are known a priori, PTP can correct for asymmetry. 1493 IEC 61850 defines the use of IEC/IEEE 61850-9-3:2016. The title is: 1494 Precision time protocol profile for power utility automation. It is 1495 based on Annex B/IEC 62439 which offers the support of redundant 1496 attachment of clocks to Parallel Redundancy Protocol (PRP) and High- 1497 availability Seamless Redundancy (HSR) networks. 1499 3.3.3. Security Trends in Utility Networks 1501 Although advanced telecommunications networks can assist in 1502 transforming the energy industry by playing a critical role in 1503 maintaining high levels of reliability, performance, and 1504 manageability, they also introduce the need for an integrated 1505 security infrastructure. Many of the technologies being deployed to 1506 support smart grid projects such as smart meters and sensors can 1507 increase the vulnerability of the grid to attack. Top security 1508 concerns for utilities migrating to an intelligent smart grid 1509 telecommunications platform center on the following trends: 1511 o Integration of distributed energy resources 1513 o Proliferation of digital devices to enable management, automation, 1514 protection, and control 1516 o Regulatory mandates to comply with standards for critical 1517 infrastructure protection 1519 o Migration to new systems for outage management, distribution 1520 automation, condition-based maintenance, load forecasting, and 1521 smart metering 1523 o Demand for new levels of customer service and energy management 1525 This development of a diverse set of networks to support the 1526 integration of microgrids, open-access energy competition, and the 1527 use of network-controlled devices is driving the need for a converged 1528 security infrastructure for all participants in the smart grid, 1529 including utilities, energy service providers, large commercial and 1530 industrial, as well as residential customers. Securing the assets of 1531 electric power delivery systems (from the control center to the 1532 substation, to the feeders and down to customer meters) requires an 1533 end-to-end security infrastructure that protects the myriad of 1534 telecommunications assets used to operate, monitor, and control power 1535 flow and measurement. 1537 "Cyber security" refers to all the security issues in automation and 1538 telecommunications that affect any functions related to the operation 1539 of the electric power systems. Specifically, it involves the 1540 concepts of: 1542 o Integrity : data cannot be altered undetectably 1544 o Authenticity : the telecommunications parties involved must be 1545 validated as genuine 1547 o Authorization : only requests and commands from the authorized 1548 users can be accepted by the system 1550 o Confidentiality : data must not be accessible to any 1551 unauthenticated users 1553 When designing and deploying new smart grid devices and 1554 telecommunications systems, it is imperative to understand the 1555 various impacts of these new components under a variety of attack 1556 situations on the power grid. Consequences of a cyber attack on the 1557 grid telecommunications network can be catastrophic. This is why 1558 security for smart grid is not just an ad hoc feature or product, 1559 it's a complete framework integrating both physical and Cyber 1560 security requirements and covering the entire smart grid networks 1561 from generation to distribution. Security has therefore become one 1562 of the main foundations of the utility telecom network architecture 1563 and must be considered at every layer with a defense-in-depth 1564 approach. Migrating to IP based protocols is key to address these 1565 challenges for two reasons: 1567 o IP enables a rich set of features and capabilities to enhance the 1568 security posture 1570 o IP is based on open standards, which allows interoperability 1571 between different vendors and products, driving down the costs 1572 associated with implementing security solutions in OT networks. 1574 Securing OT (Operation technology) telecommunications over packet- 1575 switched IP networks follow the same principles that are foundational 1576 for securing the IT infrastructure, i.e., consideration must be given 1577 to enforcing electronic access control for both person-to-machine and 1578 machine-to-machine communications, and providing the appropriate 1579 levels of data privacy, device and platform integrity, and threat 1580 detection and mitigation. 1582 3.4. Electrical Utilities Asks 1584 o Mixed L2 and L3 topologies 1586 o Deterministic behavior 1588 o Bounded latency and jitter 1590 o Tight feedback intervals 1592 o High availability, low recovery time 1594 o Redundancy, low packet loss 1596 o Precise timing 1598 o Centralized computing of deterministic paths 1600 o Distributed configuration may also be useful 1602 4. Building Automation Systems 1604 4.1. Use Case Description 1606 A Building Automation System (BAS) manages equipment and sensors in a 1607 building for improving residents' comfort, reducing energy 1608 consumption, and responding to failures and emergencies. For 1609 example, the BAS measures the temperature of a room using sensors and 1610 then controls the HVAC (heating, ventilating, and air conditioning) 1611 to maintain a set temperature and minimize energy consumption. 1613 A BAS primarily performs the following functions: 1615 o Periodically measures states of devices, for example humidity and 1616 illuminance of rooms, open/close state of doors, FAN speed, etc. 1618 o Stores the measured data. 1620 o Provides the measured data to BAS systems and operators. 1622 o Generates alarms for abnormal state of devices. 1624 o Controls devices (e.g. turn off room lights at 10:00 PM). 1626 4.2. Building Automation Systems Today 1628 4.2.1. BAS Architecture 1630 A typical BAS architecture of today is shown in Figure 4. 1632 +----------------------------+ 1633 | | 1634 | BMS HMI | 1635 | | | | 1636 | +----------------------+ | 1637 | | Management Network | | 1638 | +----------------------+ | 1639 | | | | 1640 | LC LC | 1641 | | | | 1642 | +----------------------+ | 1643 | | Field Network | | 1644 | +----------------------+ | 1645 | | | | | | 1646 | Dev Dev Dev Dev | 1647 | | 1648 +----------------------------+ 1650 BMS := Building Management Server 1651 HMI := Human Machine Interface 1652 LC := Local Controller 1654 Figure 4: BAS architecture 1656 There are typically two layers of network in a BAS. The upper one is 1657 called the Management Network and the lower one is called the Field 1658 Network. In management networks an IP-based communication protocol 1659 is used, while in field networks non-IP based communication protocols 1660 ("field protocols") are mainly used. Field networks have specific 1661 timing requirements, whereas management networks can be best-effort. 1663 A Human Machine Interface (HMI) is typically a desktop PC used by 1664 operators to monitor and display device states, send device control 1665 commands to Local Controllers (LCs), and configure building schedules 1666 (for example "turn off all room lights in the building at 10:00 PM"). 1668 A Building Management Server (BMS) performs the following operations. 1670 o Collect and store device states from LCs at regular intervals. 1672 o Send control values to LCs according to a building schedule. 1674 o Send an alarm signal to operators if it detects abnormal devices 1675 states. 1677 The BMS and HMI communicate with LCs via IP-based "management 1678 protocols" (see standards [bacnetip], [knx]). 1680 A LC is typically a Programmable Logic Controller (PLC) which is 1681 connected to several tens or hundreds of devices using "field 1682 protocols". An LC performs the following kinds of operations: 1684 o Measure device states and provide the information to BMS or HMI. 1686 o Send control values to devices, unilaterally or as part of a 1687 feedback control loop. 1689 There are many field protocols used today; some are standards-based 1690 and others are proprietary (see standards [lontalk], [modbus], 1691 [profibus] and [flnet]). The result is that BASs have multiple MAC/ 1692 PHY modules and interfaces. This makes BASs more expensive, slower 1693 to develop, and can result in "vendor lock-in" with multiple types of 1694 management applications. 1696 4.2.2. BAS Deployment Model 1698 An example BAS for medium or large buildings is shown in Figure 5. 1699 The physical layout spans multiple floors, and there is a monitoring 1700 room where the BAS management entities are located. Each floor will 1701 have one or more LCs depending upon the number of devices connected 1702 to the field network. 1704 +--------------------------------------------------+ 1705 | Floor 3 | 1706 | +----LC~~~~+~~~~~+~~~~~+ | 1707 | | | | | | 1708 | | Dev Dev Dev | 1709 | | | 1710 |--- | ------------------------------------------| 1711 | | Floor 2 | 1712 | +----LC~~~~+~~~~~+~~~~~+ Field Network | 1713 | | | | | | 1714 | | Dev Dev Dev | 1715 | | | 1716 |--- | ------------------------------------------| 1717 | | Floor 1 | 1718 | +----LC~~~~+~~~~~+~~~~~+ +-----------------| 1719 | | | | | | Monitoring Room | 1720 | | Dev Dev Dev | | 1721 | | | BMS HMI | 1722 | | Management Network | | | | 1723 | +--------------------------------+-----+ | 1724 | | | 1725 +--------------------------------------------------+ 1727 Figure 5: BAS Deployment model for Medium/Large Buildings 1729 Each LC is connected to the monitoring room via the Management 1730 network, and the management functions are performed within the 1731 building. In most cases, fast Ethernet (e.g. 100BASE-T) is used for 1732 the management network. Since the management network is non- 1733 realtime, use of Ethernet without quality of service is sufficient 1734 for today's deployment. 1736 In the field network a variety of physical interfaces such as RS232C 1737 and RS485 are used, which have specific timing requirements. Thus if 1738 a field network is to be replaced with an Ethernet or wireless 1739 network, such networks must support time-critical deterministic 1740 flows. 1742 In Figure 6, another deployment model is presented in which the 1743 management system is hosted remotely. This is becoming popular for 1744 small office and residential buildings in which a standalone 1745 monitoring system is not cost-effective. 1747 +---------------+ 1748 | Remote Center | 1749 | | 1750 | BMS HMI | 1751 +------------------------------------+ | | | | 1752 | Floor 2 | | +---+---+ | 1753 | +----LC~~~~+~~~~~+ Field Network| | | | 1754 | | | | | | Router | 1755 | | Dev Dev | +-------|-------+ 1756 | | | | 1757 |--- | ------------------------------| | 1758 | | Floor 1 | | 1759 | +----LC~~~~+~~~~~+ | | 1760 | | | | | | 1761 | | Dev Dev | | 1762 | | | | 1763 | | Management Network | WAN | 1764 | +------------------------Router-------------+ 1765 | | 1766 +------------------------------------+ 1768 Figure 6: Deployment model for Small Buildings 1770 Some interoperability is possible today in the Management Network, 1771 but not in today's field networks due to their non-IP-based design. 1773 4.2.3. Use Cases for Field Networks 1775 Below are use cases for Environmental Monitoring, Fire Detection, and 1776 Feedback Control, and their implications for field network 1777 performance. 1779 4.2.3.1. Environmental Monitoring 1781 The BMS polls each LC at a maximum measurement interval of 100ms (for 1782 example to draw a historical chart of 1 second granularity with a 10x 1783 sampling interval) and then performs the operations as specified by 1784 the operator. Each LC needs to measure each of its several hundred 1785 sensors once per measurement interval. Latency is not critical in 1786 this scenario as long as all sensor values are completed in the 1787 measurement interval. Availability is expected to be 99.999 %. 1789 4.2.3.2. Fire Detection 1791 On detection of a fire, the BMS must stop the HVAC, close the fire 1792 shutters, turn on the fire sprinklers, send an alarm, etc. There are 1793 typically ~10s of sensors per LC that BMS needs to manage. In this 1794 scenario the measurement interval is 10-50ms, the communication delay 1795 is 10ms, and the availability must be 99.9999 %. 1797 4.2.3.3. Feedback Control 1799 BAS systems utilize feedback control in various ways; the most time- 1800 critial is control of DC motors, which require a short feedback 1801 interval (1-5ms) with low communication delay (10ms) and jitter 1802 (1ms). The feedback interval depends on the characteristics of the 1803 device and a target quality of control value. There are typically 1804 ~10s of such devices per LC. 1806 Communication delay is expected to be less than 10 ms, jitter less 1807 than 1 sec while the availability must be 99.9999% . 1809 4.2.4. Security Considerations 1811 When BAS field networks were developed it was assumed that the field 1812 networks would always be physically isolated from external networks 1813 and therefore security was not a concern. In today's world many BASs 1814 are managed remotely and are thus connected to shared IP networks and 1815 so security is definitely a concern, yet security features are not 1816 available in the majority of BAS field network deployments . 1818 The management network, being an IP-based network, has the protocols 1819 available to enable network security, but in practice many BAS 1820 systems do not implement even the available security features such as 1821 device authentication or encryption for data in transit. 1823 4.3. BAS Future 1825 In the future we expect more fine-grained environmental monitoring 1826 and lower energy consumption, which will require more sensors and 1827 devices, thus requiring larger and more complex building networks. 1829 We expect building networks to be connected to or converged with 1830 other networks (Enterprise network, Home network, and Internet). 1832 Therefore better facilities for network management, control, 1833 reliability and security are critical in order to improve resident 1834 and operator convenience and comfort. For example the ability to 1835 monitor and control building devices via the internet would enable 1836 (for example) control of room lights or HVAC from a resident's 1837 desktop PC or phone application. 1839 4.4. BAS Asks 1841 The community would like to see an interoperable protocol 1842 specification that can satisfy the timing, security, availability and 1843 QoS constraints described above, such that the resulting converged 1844 network can replace the disparate field networks. Ideally this 1845 connectivity could extend to the open Internet. 1847 This would imply an architecture that can guarantee 1849 o Low communication delays (from <10ms to 100ms in a network of 1850 several hundred devices) 1852 o Low jitter (< 1 ms) 1854 o Tight feedback intervals (1ms - 10ms) 1856 o High network availability (up to 99.9999% ) 1858 o Availability of network data in disaster scenario 1860 o Authentication between management and field devices (both local 1861 and remote) 1863 o Integrity and data origin authentication of communication data 1864 between field and management devices 1866 o Confidentiality of data when communicated to a remote device 1868 5. Wireless for Industrial 1870 5.1. Use Case Description 1872 Wireless networks are useful for industrial applications, for example 1873 when portable, fast-moving or rotating objects are involved, and for 1874 the resource-constrained devices found in the Internet of Things 1875 (IoT). 1877 Such network-connected sensors, actuators, control loops (etc.) 1878 typically require that the underlying network support real-time 1879 quality of service (QoS), as well as specific classes of other 1880 network properties such as reliability, redundancy, and security. 1882 These networks may also contain very large numbers of devices, for 1883 example for factories, "big data" acquisition, and the IoT. Given 1884 the large numbers of devices installed, and the potential 1885 pervasiveness of the IoT, this is a huge and very cost-sensitive 1886 market. For example, a 1% cost reduction in some areas could save 1887 $100B 1889 5.1.1. Network Convergence using 6TiSCH 1891 Some wireless network technologies support real-time QoS, and are 1892 thus useful for these kinds of networks, but others do not. For 1893 example WiFi is pervasive but does not provide guaranteed timing or 1894 delivery of packets, and thus is not useful in this context. 1896 In this use case we focus on one specific wireless network technology 1897 which does provide the required deterministic QoS, which is "IPv6 1898 over the TSCH mode of IEEE 802.15.4e" (6TiSCH, where TSCH stands for 1899 "Time-Slotted Channel Hopping", see [I-D.ietf-6tisch-architecture], 1900 [IEEE802154], [IEEE802154e], and [RFC7554]). 1902 There are other deterministic wireless busses and networks available 1903 today, however they are imcompatible with each other, and 1904 incompatible with IP traffic (for example [ISA100], [WirelessHART]). 1906 Thus the primary goal of this use case is to apply 6TiSCH as a 1907 converged IP- and standards-based wireless network for industrial 1908 applications, i.e. to replace multiple proprietary and/or 1909 incompatible wireless networking and wireless network management 1910 standards. 1912 5.1.2. Common Protocol Development for 6TiSCH 1914 Today there are a number of protocols required by 6TiSCH which are 1915 still in development, and a second intent of this use case is to 1916 highlight the ways in which these "missing" protocols share goals in 1917 common with DetNet. Thus it is possible that some of the protocol 1918 technology developed for DetNet will also be applicable to 6TiSCH. 1920 These protocol goals are identified here, along with their 1921 relationship to DetNet. It is likely that ultimately the resulting 1922 protocols will not be identical, but will share design principles 1923 which contribute to the eficiency of enabling both DetNet and 6TiSCH. 1925 One such commonality is that although at a different time scale, in 1926 both TSN [IEEE802.1TSNTG] and TSCH a packet crosses the network from 1927 node to node follows a precise schedule, as a train that leaves 1928 intermediate stations at precise times along its path. This kind of 1929 operation reduces collisions, saves energy, and enables engineering 1930 the network for deterministic properties. 1932 Another commonality is remote monitoring and scheduling management of 1933 a TSCH network by a Path Computation Element (PCE) and Network 1934 Management Entity (NME). The PCE/NME manage timeslots and device 1935 resources in a manner that minimizes the interaction with and the 1936 load placed on resource-constrained devices. For example, a tiny IoT 1937 device may have just enough buffers to store one or a few IPv6 1938 packets, and will have limited bandwidth between peers such that it 1939 can maintain only a small amount of peer information, and will not be 1940 able to store many packets waiting to be forwarded. It is 1941 advantageous then for it to only be required to carry out the 1942 specific behavior assigned to it by the PCE/NME (as opposed to 1943 maintaining its own IP stack, for example). 1945 Note: Current WG discussion indicates that some peer-to-peer 1946 communication must be assumed, i.e. the PCE may communicate only 1947 indirectly with any given device, enabling hierarchical configuration 1948 of the system. 1950 6TiSCH depends on [PCE] and [I-D.finn-detnet-architecture]. 1952 6TiSCH also depends on the fact that DetNet will maintain consistency 1953 with [IEEE802.1TSNTG]. 1955 5.2. Wireless Industrial Today 1957 Today industrial wireless is accomplished using multiple 1958 deterministic wireless networks which are incompatible with each 1959 other and with IP traffic. 1961 6TiSCH is not yet fully specified, so it cannot be used in today's 1962 applications. 1964 5.3. Wireless Industrial Future 1966 5.3.1. Unified Wireless Network and Management 1968 We expect DetNet and 6TiSCH together to enable converged transport of 1969 deterministic and best-effort traffic flows between real-time 1970 industrial devices and wide area networks via IP routing. A high 1971 level view of a basic such network is shown in Figure 7. 1973 ---+-------- ............ ------------ 1974 | External Network | 1975 | +-----+ 1976 +-----+ | NME | 1977 | | LLN Border | | 1978 | | router +-----+ 1979 +-----+ 1980 o o o 1981 o o o o 1982 o o LLN o o o 1983 o o o o 1984 o 1986 Figure 7: Basic 6TiSCH Network 1988 Figure 8 shows a backbone router federating multiple synchronized 1989 6TiSCH subnets into a single subnet connected to the external 1990 network. 1992 ---+-------- ............ ------------ 1993 | External Network | 1994 | +-----+ 1995 | +-----+ | NME | 1996 +-----+ | +-----+ | | 1997 | | Router | | PCE | +-----+ 1998 | | +--| | 1999 +-----+ +-----+ 2000 | | 2001 | Subnet Backbone | 2002 +--------------------+------------------+ 2003 | | | 2004 +-----+ +-----+ +-----+ 2005 | | Backbone | | Backbone | | Backbone 2006 o | | router | | router | | router 2007 +-----+ +-----+ +-----+ 2008 o o o o o 2009 o o o o o o o o o o o 2010 o o o LLN o o o o 2011 o o o o o o o o o o o o 2013 Figure 8: Extended 6TiSCH Network 2015 The backbone router must ensure end-to-end deterministic behavior 2016 between the LLN and the backbone. We would like to see this 2017 accomplished in conformance with the work done in 2018 [I-D.finn-detnet-architecture] with respect to Layer-3 aspects of 2019 deterministic networks that span multiple Layer-2 domains. 2021 The PCE must compute a deterministic path end-to-end across the TSCH 2022 network and IEEE802.1 TSN Ethernet backbone, and DetNet protocols are 2023 expected to enable end-to-end deterministic forwarding. 2025 +-----+ 2026 | IoT | 2027 | G/W | 2028 +-----+ 2029 ^ <---- Elimination 2030 | | 2031 Track branch | | 2032 +-------+ +--------+ Subnet Backbone 2033 | | 2034 +--|--+ +--|--+ 2035 | | | Backbone | | | Backbone 2036 o | | | router | | | router 2037 +--/--+ +--|--+ 2038 o / o o---o----/ o 2039 o o---o--/ o o o o o 2040 o \ / o o LLN o 2041 o v <---- Replication 2042 o 2044 Figure 9: 6TiSCH Network with PRE 2046 5.3.1.1. PCE and 6TiSCH ARQ Retries 2048 Note: The possible use of ARQ techniques in DetNet is currently 2049 considered a possible design alternative. 2051 6TiSCH uses the IEEE802.15.4 Automatic Repeat-reQuest (ARQ) mechanism 2052 to provide higher reliability of packet delivery. ARQ is related to 2053 packet replication and elimination because there are two independent 2054 paths for packets to arrive at the destination, and if an expected 2055 packed does not arrive on one path then it checks for the packet on 2056 the second path. 2058 Although to date this mechanism is only used by wireless networks, 2059 this may be a technique that would be appropriate for DetNet and so 2060 aspects of the enabling protocol could be co-developed. 2062 For example, in Figure 9, a Track is laid out from a field device in 2063 a 6TiSCH network to an IoT gateway that is located on a IEEE802.1 TSN 2064 backbone. 2066 In ARQ the Replication function in the field device sends a copy of 2067 each packet over two different branches, and the PCE schedules each 2068 hop of both branches so that the two copies arrive in due time at the 2069 gateway. In case of a loss on one branch, hopefully the other copy 2070 of the packet still arrives within the allocated time. If two copies 2071 make it to the IoT gateway, the Elimination function in the gateway 2072 ignores the extra packet and presents only one copy to upper layers. 2074 At each 6TiSCH hop along the Track, the PCE may schedule more than 2075 one timeSlot for a packet, so as to support Layer-2 retries (ARQ). 2077 In current deployments, a TSCH Track does not necessarily support PRE 2078 but is systematically multi-path. This means that a Track is 2079 scheduled so as to ensure that each hop has at least two forwarding 2080 solutions, and the forwarding decision is to try the preferred one 2081 and use the other in case of Layer-2 transmission failure as detected 2082 by ARQ. 2084 5.3.2. Schedule Management by a PCE 2086 A common feature of 6TiSCH and DetNet is the action of a PCE to 2087 configure paths through the network. Specifically, what is needed is 2088 a protocol and data model that the PCE will use to get/set the 2089 relevant configuration from/to the devices, as well as perform 2090 operations on the devices. We expect that this protocol will be 2091 developed by DetNet with consideration for its reuse by 6TiSCH. The 2092 remainder of this section provides a bit more context from the 6TiSCH 2093 side. 2095 5.3.2.1. PCE Commands and 6TiSCH CoAP Requests 2097 The 6TiSCH device does not expect to place the request for bandwidth 2098 between itself and another device in the network. Rather, an 2099 operation control system invoked through a human interface specifies 2100 the required traffic specification and the end nodes (in terms of 2101 latency and reliability). Based on this information, the PCE must 2102 compute a path between the end nodes and provision the network with 2103 per-flow state that describes the per-hop operation for a given 2104 packet, the corresponding timeslots, and the flow identification that 2105 enables recognizing that a certain packet belongs to a certain path, 2106 etc. 2108 For a static configuration that serves a certain purpose for a long 2109 period of time, it is expected that a node will be provisioned in one 2110 shot with a full schedule, which incorporates the aggregation of its 2111 behavior for multiple paths. 6TiSCH expects that the programing of 2112 the schedule will be done over COAP as discussed in 2113 [I-D.ietf-6tisch-coap]. 2115 6TiSCH expects that the PCE commands will be mapped back and forth 2116 into CoAP by a gateway function at the edge of the 6TiSCH network. 2117 For instance, it is possible that a mapping entity on the backbone 2118 transforms a non-CoAP protocol such as PCEP into the RESTful 2119 interfaces that the 6TiSCH devices support. This architecture will 2120 be refined to comply with DetNet [I-D.finn-detnet-architecture] when 2121 the work is formalized. Related information about 6TiSCH can be 2122 found at [I-D.ietf-6tisch-6top-interface] and RPL [RFC6550]. 2124 A protocol may be used to update the state in the devices during 2125 runtime, for example if it appears that a path through the network 2126 has ceased to perform as expected, but in 6TiSCH that flow was not 2127 designed and no protocol was selected. We would like to see DetNet 2128 define the appropriate end-to-end protocols to be used in that case. 2129 The implication is that these state updates take place once the 2130 system is configured and running, i.e. they are not limited to the 2131 initial communication of the configuration of the system. 2133 A "slotFrame" is the base object that a PCE would manipulate to 2134 program a schedule into an LLN node ([I-D.ietf-6tisch-architecture]). 2136 We would like to see the PCE read energy data from devices, and 2137 compute paths that will implement policies on how energy in devices 2138 is consumed, for instance to ensure that the spent energy does not 2139 exceeded the available energy over a period of time. Note: this 2140 statement implies that an extensible protocol for communicating 2141 device info to the PCE and enabling the PCE to act on it will be part 2142 of the DetNet architecture, however for subnets with specific 2143 protocols (e.g. CoAP) a gateway may be required. 2145 6TiSCH devices can discover their neighbors over the radio using a 2146 mechanism such as beacons, but even though the neighbor information 2147 is available in the 6TiSCH interface data model, 6TiSCH does not 2148 describe a protocol to proactively push the neighborhood information 2149 to a PCE. We would like to see DetNet define such a protocol; one 2150 possible design alternative is that it could operate over CoAP, 2151 alternatively it could be converted to/from CoAP by a gateway. We 2152 would like to see such a protocol carry multiple metrics, for example 2153 similar to those used for RPL operations [RFC6551] 2155 5.3.2.2. 6TiSCH IP Interface 2157 "6top" ([I-D.wang-6tisch-6top-sublayer]) is a logical link control 2158 sitting between the IP layer and the TSCH MAC layer which provides 2159 the link abstraction that is required for IP operations. The 6top 2160 data model and management interfaces are further discussed in 2161 [I-D.ietf-6tisch-6top-interface] and [I-D.ietf-6tisch-coap]. 2163 An IP packet that is sent along a 6TiSCH path uses the Differentiated 2164 Services Per-Hop-Behavior Group called Deterministic Forwarding, as 2165 described in [I-D.svshah-tsvwg-deterministic-forwarding]. 2167 5.3.3. 6TiSCH Security Considerations 2169 On top of the classical requirements for protection of control 2170 signaling, it must be noted that 6TiSCH networks operate on limited 2171 resources that can be depleted rapidly in a DoS attack on the system, 2172 for instance by placing a rogue device in the network, or by 2173 obtaining management control and setting up unexpected additional 2174 paths. 2176 5.4. Wireless Industrial Asks 2178 6TiSCH depends on DetNet to define: 2180 o Configuration (state) and operations for deterministic paths 2182 o End-to-end protocols for deterministic forwarding (tagging, IP) 2184 o Protocol for packet replication and elimination 2186 6. Cellular Radio 2188 6.1. Use Case Description 2190 This use case describes the application of deterministic networking 2191 in the context of cellular telecom transport networks. Important 2192 elements include time synchronization, clock distribution, and ways 2193 of establishing time-sensitive streams for both Layer-2 and Layer-3 2194 user plane traffic. 2196 6.1.1. Network Architecture 2198 Figure 10 illustrates a typical 3GPP-defined cellular network 2199 architecture, which includes "Fronthaul", "Midhaul" and "Backhaul" 2200 network segments. The "Fronthaul" is the network connecting base 2201 stations (baseband processing units) to the remote radio heads 2202 (antennas). The "Midhaul" is the network inter-connecting base 2203 stations (or small cell sites). The "Backhaul" is the network or 2204 links connecting the radio base station sites to the network 2205 controller/gateway sites (i.e. the core of the 3GPP cellular 2206 network). 2208 In Figure 10 "eNB" ("E-UTRAN Node B") is the hardware that is 2209 connected to the mobile phone network which communicates directly 2210 with mobile handsets ([TS36300]). 2212 Y (remote radio heads (antennas)) 2213 \ 2214 Y__ \.--. .--. +------+ 2215 \_( `. +---+ _(Back`. | 3GPP | 2216 Y------( Front )----|eNB|----( Haul )----| core | 2217 ( ` .Haul ) +---+ ( ` . ) ) | netw | 2218 /`--(___.-' \ `--(___.-' +------+ 2219 Y_/ / \.--. \ 2220 Y_/ _( Mid`. \ 2221 ( Haul ) \ 2222 ( ` . ) ) \ 2223 `--(___.-'\_____+---+ (small cell sites) 2224 \ |SCe|__Y 2225 +---+ +---+ 2226 Y__|eNB|__Y 2227 +---+ 2228 Y_/ \_Y ("local" radios) 2230 Figure 10: Generic 3GPP-based Cellular Network Architecture 2232 6.1.2. Delay Constraints 2234 The available processing time for Fronthaul networking overhead is 2235 limited to the available time after the baseband processing of the 2236 radio frame has completed. For example in Long Term Evolution (LTE) 2237 radio, processing of a radio frame is allocated 3ms but typically the 2238 processing uses most of it, allowing only a small fraction to be used 2239 by the Fronthaul network (e.g. up to 250us one-way delay, though the 2240 existing spec ([NGMN-fronth]) supports delay only up to 100us). This 2241 ultimately determines the distance the remote radio heads can be 2242 located from the base stations (e.g., 100us equals roughly 20 km of 2243 optical fiber-based transport). Allocation options of the available 2244 time budget between processing and transport are under heavy 2245 discussions in the mobile industry. 2247 For packet-based transport the allocated transport time (e.g. CPRI 2248 would allow for 100us delay [CPRI]) is consumed by all nodes and 2249 buffering between the remote radio head and the baseband processing 2250 unit, plus the distance-incurred delay. 2252 The baseband processing time and the available "delay budget" for the 2253 fronthaul is likely to change in the forthcoming "5G" due to reduced 2254 radio round trip times and other architectural and service 2255 requirements [NGMN]. 2257 The transport time budget, as noted above, places limitations on the 2258 distance that remote radio heads can be located from base stations 2259 (i.e. the link length). In the above analysis, the entire transport 2260 time budget is assumed to be available for link propagation delay. 2261 However the transport time budget can be broken down into three 2262 components: scheduling /queueing delay, transmission delay, and link 2263 propagation delay. Using today's Fronthaul networking technology, 2264 the queuing, scheduling and transmission components might become the 2265 dominant factors in the total transport time rather than the link 2266 propagation delay. This is especially true in cases where the 2267 Fronthaul link is relatively short and it is shared among multiple 2268 Fronthaul flows, for example in indoor and small cell networks, 2269 massive MIMO antenna networks, and split Fronthaul architectures. 2271 DetNet technology can improve this application by controlling and 2272 reducing the time required for the queuing, scheduling and 2273 transmission operations by properly assigning the network resources, 2274 thus leaving more of the transport time budget available for link 2275 propagation, and thus enabling longer link lengths. However, link 2276 length is usually a given parameter and is not a controllable network 2277 parameter, since RRH and BBU sights are usually located in 2278 predetermined locations. However, the number of antennas in an RRH 2279 sight might increase for example by adding more antennas, increasing 2280 the MIMO capability of the network or support of massive MIMO. This 2281 means increasing the number of the fronthaul flows sharing the same 2282 fronthaul link. DetNet can now control the bandwidth assignment of 2283 the fronthaul link and the scheduling of fronthaul packets over this 2284 link and provide adequate buffer provisioning for each flow to reduce 2285 the packet loss rate. 2287 Another way in which DetNet technology can aid Fronthaul networks is 2288 by providing effective isolation from best-effort (and other classes 2289 of) traffic, which can arise as a result of network slicing in 5G 2290 networks where Fronthaul traffic generated in different network 2291 slices might have differing performance requirements. DetNet 2292 technology can also dynamically control the bandwidth assignment, 2293 scheduling and packet forwarding decisions and the buffer 2294 provisioning of the Fronthaul flows to guarantee the end-to-end delay 2295 of the Fronthaul packets and minimize the packet loss rate. 2297 [METIS] documents the fundamental challenges as well as overall 2298 technical goals of the future 5G mobile and wireless system as the 2299 starting point. These future systems should support much higher data 2300 volumes and rates and significantly lower end-to-end latency for 100x 2301 more connected devices (at similar cost and energy consumption levels 2302 as today's system). 2304 For Midhaul connections, delay constraints are driven by Inter-Site 2305 radio functions like Coordinated Multipoint Processing (CoMP, see 2306 [CoMP]). CoMP reception and transmission is a framework in which 2307 multiple geographically distributed antenna nodes cooperate to 2308 improve the performance of the users served in the common cooperation 2309 area. The design principal of CoMP is to extend the current single- 2310 cell to multi-UE (User Equipment) transmission to a multi-cell-to- 2311 multi-UEs transmission by base station cooperation. 2313 CoMP has delay-sensitive performance parameters, which are "midhaul 2314 latency" and "CSI (Channel State Information) reporting and 2315 accuracy". The essential feature of CoMP is signaling between eNBs, 2316 so Midhaul latency is the dominating limitation of CoMP performance. 2317 Generally, CoMP can benefit from coordinated scheduling (either 2318 distributed or centralized) of different cells if the signaling delay 2319 between eNBs is within 1-10ms. This delay requirement is both rigid 2320 and absolute because any uncertainty in delay will degrade the 2321 performance significantly. 2323 Inter-site CoMP is one of the key requirements for 5G and is also a 2324 near-term goal for the current 4.5G network architecture. 2326 6.1.3. Time Synchronization Constraints 2328 Fronthaul time synchronization requirements are given by [TS25104], 2329 [TS36104], [TS36211], and [TS36133]. These can be summarized for the 2330 current 3GPP LTE-based networks as: 2332 Delay Accuracy: 2333 +-8ns (i.e. +-1/32 Tc, where Tc is the UMTS Chip time of 1/3.84 2334 MHz) resulting in a round trip accuracy of +-16ns. The value is 2335 this low to meet the 3GPP Timing Alignment Error (TAE) measurement 2336 requirements. Note: performance guarantees of low nanosecond 2337 values such as these are considered to be below the DetNet layer - 2338 it is assumed that the underlying implementation, e.g. the 2339 hardware, will provide sufficient support (e.g. buffering) to 2340 enable this level of accuracy. These values are maintained in the 2341 use case to give an indication of the overall application. 2343 Timing Alignment Error: 2344 Timing Alignment Error (TAE) is problematic to Fronthaul networks 2345 and must be minimized. If the transport network cannot guarantee 2346 low enough TAE then additional buffering has to be introduced at 2347 the edges of the network to buffer out the jitter. Buffering is 2348 not desirable as it reduces the total available delay budget. 2349 Packet Delay Variation (PDV) requirements can be derived from TAE 2350 for packet based Fronthaul networks. 2352 * For multiple input multiple output (MIMO) or TX diversity 2353 transmissions, at each carrier frequency, TAE shall not exceed 2354 65 ns (i.e. 1/4 Tc). 2356 * For intra-band contiguous carrier aggregation, with or without 2357 MIMO or TX diversity, TAE shall not exceed 130 ns (i.e. 1/2 2358 Tc). 2360 * For intra-band non-contiguous carrier aggregation, with or 2361 without MIMO or TX diversity, TAE shall not exceed 260 ns (i.e. 2362 one Tc). 2364 * For inter-band carrier aggregation, with or without MIMO or TX 2365 diversity, TAE shall not exceed 260 ns. 2367 Transport link contribution to radio frequency error: 2368 +-2 PPB. This value is considered to be "available" for the 2369 Fronthaul link out of the total 50 PPB budget reserved for the 2370 radio interface. Note: the reason that the transport link 2371 contributes to radio frequency error is as follows. The current 2372 way of doing Fronthaul is from the radio unit to remote radio head 2373 directly. The remote radio head is essentially a passive device 2374 (without buffering etc.) The transport drives the antenna 2375 directly by feeding it with samples and everything the transport 2376 adds will be introduced to radio as-is. So if the transport 2377 causes additional frequency error that shows immediately on the 2378 radio as well. Note: performance guarantees of low nanosecond 2379 values such as these are considered to be below the DetNet layer - 2380 it is assumed that the underlying implementation, e.g. the 2381 hardware, will provide sufficient support to enable this level of 2382 performance. These values are maintained in the use case to give 2383 an indication of the overall application. 2385 The above listed time synchronization requirements are difficult to 2386 meet with point-to-point connected networks, and more difficult when 2387 the network includes multiple hops. It is expected that networks 2388 must include buffering at the ends of the connections as imposed by 2389 the jitter requirements, since trying to meet the jitter requirements 2390 in every intermediate node is likely to be too costly. However, 2391 every measure to reduce jitter and delay on the path makes it easier 2392 to meet the end-to-end requirements. 2394 In order to meet the timing requirements both senders and receivers 2395 must remain time synchronized, demanding very accurate clock 2396 distribution, for example support for IEEE 1588 transparent clocks or 2397 boundary clocks in every intermediate node. 2399 In cellular networks from the LTE radio era onward, phase 2400 synchronization is needed in addition to frequency synchronization 2401 ([TS36300], [TS23401]). Time constraints are also important due to 2402 their impact on packet loss. If a packet is delivered too late, then 2403 the packet may be dropped by the host. 2405 6.1.4. Transport Loss Constraints 2407 Fronthaul and Midhaul networks assume almost error-free transport. 2408 Errors can result in a reset of the radio interfaces, which can cause 2409 reduced throughput or broken radio connectivity for mobile customers. 2411 For packetized Fronthaul and Midhaul connections packet loss may be 2412 caused by BER, congestion, or network failure scenarios. Different 2413 fronthaul functional splits are being considered by 3GPP, requiring 2414 strict frame loss ratio (FLR) guarantees. As one example (referring 2415 to the legacy CPRI split which is option 8 in 3GPP) lower layers 2416 splits may imply an FLR of less than 10E-7 for data traffic and less 2417 than 10E-6 for control and management traffic. Current tools for 2418 eliminating packet loss for Fronthaul and Midhaul networks have 2419 serious challenges, for example retransmitting lost packets and/or 2420 using forward error correction (FEC) to circumvent bit errors is 2421 practically impossible due to the additional delay incurred. Using 2422 redundant streams for better guarantees for delivery is also 2423 practically impossible in many cases due to high bandwidth 2424 requirements of Fronthaul and Midhaul networks. Protection switching 2425 is also a candidate but current technologies for the path switch are 2426 too slow to avoid reset of mobile interfaces. 2428 Fronthaul links are assumed to be symmetric, and all Fronthaul 2429 streams (i.e. those carrying radio data) have equal priority and 2430 cannot delay or pre-empt each other. This implies that the network 2431 must guarantee that each time-sensitive flow meets their schedule. 2433 6.1.5. Security Considerations 2435 Establishing time-sensitive streams in the network entails reserving 2436 networking resources for long periods of time. It is important that 2437 these reservation requests be authenticated to prevent malicious 2438 reservation attempts from hostile nodes (or accidental 2439 misconfiguration). This is particularly important in the case where 2440 the reservation requests span administrative domains. Furthermore, 2441 the reservation information itself should be digitally signed to 2442 reduce the risk of a legitimate node pushing a stale or hostile 2443 configuration into another networking node. 2445 Note: This is considered important for the security policy of the 2446 network, but does not affect the core DetNet architecture and design. 2448 6.2. Cellular Radio Networks Today 2450 6.2.1. Fronthaul 2452 Today's Fronthaul networks typically consist of: 2454 o Dedicated point-to-point fiber connection is common 2456 o Proprietary protocols and framings 2458 o Custom equipment and no real networking 2460 Current solutions for Fronthaul are direct optical cables or 2461 Wavelength-Division Multiplexing (WDM) connections. 2463 6.2.2. Midhaul and Backhaul 2465 Today's Midhaul and Backhaul networks typically consist of: 2467 o Mostly normal IP networks, MPLS-TP, etc. 2469 o Clock distribution and sync using 1588 and SyncE 2471 Telecommunication networks in the Mid- and Backhaul are already 2472 heading towards transport networks where precise time synchronization 2473 support is one of the basic building blocks. While the transport 2474 networks themselves have practically transitioned to all-IP packet- 2475 based networks to meet the bandwidth and cost requirements, highly 2476 accurate clock distribution has become a challenge. 2478 In the past, Mid- and Backhaul connections were typically based on 2479 Time Division Multiplexing (TDM-based) and provided frequency 2480 synchronization capabilities as a part of the transport media. 2481 Alternatively other technologies such as Global Positioning System 2482 (GPS) or Synchronous Ethernet (SyncE) are used [SyncE]. 2484 Both Ethernet and IP/MPLS [RFC3031] (and PseudoWires (PWE) [RFC3985] 2485 for legacy transport support) have become popular tools to build and 2486 manage new all-IP Radio Access Networks (RANs) 2487 [I-D.kh-spring-ip-ran-use-case]. Although various timing and 2488 synchronization optimizations have already been proposed and 2489 implemented including 1588 PTP enhancements 2490 [I-D.ietf-tictoc-1588overmpls] and [I-D.ietf-mpls-residence-time], 2491 these solution are not necessarily sufficient for the forthcoming RAN 2492 architectures nor do they guarantee the more stringent time- 2493 synchronization requirements such as [CPRI]. 2495 There are also existing solutions for TDM over IP such as [RFC4553], 2496 [RFC5086], and [RFC5087], as well as TDM over Ethernet transports 2497 such as [MEF8]. 2499 6.3. Cellular Radio Networks Future 2501 Future Cellular Radio Networks will be based on a mix of different 2502 xHaul networks (xHaul = front-, mid- and backhaul), and future 2503 transport networks should be able to support all of them 2504 simultaneously. It is already envisioned today that: 2506 o Not all "cellular radio network" traffic will be IP, for example 2507 some will remain at Layer 2 (e.g. Ethernet based). DetNet 2508 solutions must address all traffic types (Layer 2, Layer 3) with 2509 the same tools and allow their transport simultaneously. 2511 o All forms of xHaul networks will need some form of DetNet 2512 solutions. For example with the advent of 5G some Backhaul 2513 traffic will also have DetNet requirements, for example traffic 2514 belonging to time-critical 5G applications. 2516 o Different splits of the functionality run on the base stations and 2517 the on-site units could co-exist on the same Fronthaul and 2518 Backhaul network. 2520 We would like to see the following in future Cellular Radio networks: 2522 o Unified standards-based transport protocols and standard 2523 networking equipment that can make use of underlying deterministic 2524 link-layer services 2526 o Unified and standards-based network management systems and 2527 protocols in all parts of the network (including Fronthaul) 2529 New radio access network deployment models and architectures may 2530 require time- sensitive networking services with strict requirements 2531 on other parts of the network that previously were not considered to 2532 be packetized at all. Time and synchronization support are already 2533 topical for Backhaul and Midhaul packet networks [MEF22.1.1] and are 2534 becoming a real issue for Fronthaul networks also. Specifically in 2535 Fronthaul networks the timing and synchronization requirements can be 2536 extreme for packet based technologies, for example, on the order of 2537 sub +-20 ns packet delay variation (PDV) and frequency accuracy of 2538 +0.002 PPM [Fronthaul]. 2540 The actual transport protocols and/or solutions to establish required 2541 transport "circuits" (pinned-down paths) for Fronthaul traffic are 2542 still undefined. Those are likely to include (but are not limited 2543 to) solutions directly over Ethernet, over IP, and using MPLS/ 2544 PseudoWire transport. 2546 Even the current time-sensitive networking features may not be 2547 sufficient for Fronthaul traffic. Therefore, having specific 2548 profiles that take the requirements of Fronthaul into account is 2549 desirable [IEEE8021CM]. 2551 Interesting and important work for time-sensitive networking has been 2552 done for Ethernet [TSNTG], which specifies the use of IEEE 1588 time 2553 precision protocol (PTP) [IEEE1588] in the context of IEEE 802.1D and 2554 IEEE 802.1Q. [IEEE8021AS] specifies a Layer 2 time synchronizing 2555 service, and other specifications such as IEEE 1722 [IEEE1722] 2556 specify Ethernet-based Layer-2 transport for time-sensitive streams. 2558 New promising work seeks to enable the transport of time-sensitive 2559 fronthaul streams in Ethernet bridged networks [IEEE8021CM]. 2560 Analogous to IEEE 1722 there is an ongoing standardization effort to 2561 define the Layer-2 transport encapsulation format for transporting 2562 radio over Ethernet (RoE) in the IEEE 1904.3 Task Force [IEEE19143]. 2564 As mentioned in Section 6.1.2, 5G communications will provide one of 2565 the most challenging cases for delay sensitive networking. In order 2566 to meet the challenges of ultra-low latency and ultra-high 2567 throughput, 3GPP has studied various "functional splits" for 5G, 2568 i.e., physical decomposition of the gNodeB base station and 2569 deployment of its functional blocks in different locations [TR38801]. 2571 These splits are numbered from split option 1 (Dual Connectivity, a 2572 split in which the radio resource control is centralized and other 2573 radio stack layers are in distributed units) to split option 8 (a 2574 PHY-RF split in which RF functionality is in a distributed unit and 2575 the rest of the radio stack is in the centralized unit), with each 2576 intermediate split having its own data rate and delay requirements. 2577 Packetized versions of different splits have recently been proposed 2578 including eCPRI [eCPRI] and RoE (as previously noted). Both provide 2579 Ethernet encapsulations, and eCPRI is also capable of IP 2580 encapsulation. 2582 All-IP RANs and xHaul networks would benefit from time 2583 synchronization and time-sensitive transport services. Although 2584 Ethernet appears to be the unifying technology for the transport, 2585 there is still a disconnect providing Layer 3 services. The protocol 2586 stack typically has a number of layers below the Ethernet Layer 2 2587 that shows up to the Layer 3 IP transport. It is not uncommon that 2588 on top of the lowest layer (optical) transport there is the first 2589 layer of Ethernet followed one or more layers of MPLS, PseudoWires 2590 and/or other tunneling protocols finally carrying the Ethernet layer 2591 visible to the user plane IP traffic. 2593 While there are existing technologies to establish circuits through 2594 the routed and switched networks (especially in MPLS/PWE space), 2595 there is still no way to signal the time synchronization and time- 2596 sensitive stream requirements/reservations for Layer-3 flows in a way 2597 that addresses the entire transport stack, including the Ethernet 2598 layers that need to be configured. 2600 Furthermore, not all "user plane" traffic will be IP. Therefore, the 2601 same solution also must address the use cases where the user plane 2602 traffic is a different layer, for example Ethernet frames. 2604 There is existing work describing the problem statement 2605 [I-D.finn-detnet-problem-statement] and the architecture 2606 [I-D.finn-detnet-architecture] for deterministic networking (DetNet) 2607 that targets solutions for time-sensitive (IP/transport) streams with 2608 deterministic properties over Ethernet-based switched networks. 2610 6.4. Cellular Radio Networks Asks 2612 A standard for data plane transport specification which is: 2614 o Unified among all xHauls (meaning that different flows with 2615 diverse DetNet requirements can coexist in the same network and 2616 traverse the same nodes without interfering with each other) 2618 o Deployed in a highly deterministic network environment 2620 o Capable of supporting multiple functional splits simultaneously, 2621 including existing Backhaul and CPRI Fronthaul and potentially new 2622 modes as defined for example in 3GPP; these goals can be supported 2623 by the existing DetNet Use Case Common Themes, notably "Mix of 2624 Deterministic and Best-Effort Traffic", "Bounded Latency", "Low 2625 Latency", "Symmetrical Path Delays", and "Deterministic Flows". 2627 o Capable of supporting Network Slicing and Multi-tenancy; these 2628 goals can be supported by the same DetNet themes noted above. 2630 o Capable of transporting both in-band and out-band control traffic 2631 (OAM info, ...). 2633 o Deployable over multiple data link technologies (e.g., IEEE 802.3, 2634 mmWave, etc.). 2636 A standard for data flow information models that are: 2638 o Aware of the time sensitivity and constraints of the target 2639 networking environment 2641 o Aware of underlying deterministic networking services (e.g., on 2642 the Ethernet layer) 2644 7. Industrial M2M 2646 7.1. Use Case Description 2648 Industrial Automation in general refers to automation of 2649 manufacturing, quality control and material processing. In this 2650 "machine to machine" (M2M) use case we consider machine units in a 2651 plant floor which periodically exchange data with upstream or 2652 downstream machine modules and/or a supervisory controller within a 2653 local area network. 2655 The actors of M2M communication are Programmable Logic Controllers 2656 (PLCs). Communication between PLCs and between PLCs and the 2657 supervisory PLC (S-PLC) is achieved via critical control/data streams 2658 Figure 11. 2660 S (Sensor) 2661 \ +-----+ 2662 PLC__ \.--. .--. ---| MES | 2663 \_( `. _( `./ +-----+ 2664 A------( Local )-------------( L2 ) 2665 ( Net ) ( Net ) +-------+ 2666 /`--(___.-' `--(___.-' ----| S-PLC | 2667 S_/ / PLC .--. / +-------+ 2668 A_/ \_( `. 2669 (Actuator) ( Local ) 2670 ( Net ) 2671 /`--(___.-'\ 2672 / \ A 2673 S A 2675 Figure 11: Current Generic Industrial M2M Network Architecture 2677 This use case focuses on PLC-related communications; communication to 2678 Manufacturing-Execution-Systems (MESs) are not addressed. 2680 This use case covers only critical control/data streams; non-critical 2681 traffic between industrial automation applications (such as 2682 communication of state, configuration, set-up, and database 2683 communication) are adequately served by currently available 2684 prioritizing techniques. Such traffic can use up to 80% of the total 2685 bandwidth required. There is also a subset of non-time-critical 2686 traffic that must be reliable even though it is not time sensitive. 2688 In this use case the primary need for deterministic networking is to 2689 provide end-to-end delivery of M2M messages within specific timing 2690 constraints, for example in closed loop automation control. Today 2691 this level of determinism is provided by proprietary networking 2692 technologies. In addition, standard networking technologies are used 2693 to connect the local network to remote industrial automation sites, 2694 e.g. over an enterprise or metro network which also carries other 2695 types of traffic. Therefore, flows that should be forwarded with 2696 deterministic guarantees need to be sustained regardless of the 2697 amount of other flows in those networks. 2699 7.2. Industrial M2M Communication Today 2701 Today, proprietary networks fulfill the needed timing and 2702 availability for M2M networks. 2704 The network topologies used today by industrial automation are 2705 similar to those used by telecom networks: Daisy Chain, Ring, Hub and 2706 Spoke, and Comb (a subset of Daisy Chain). 2708 PLC-related control/data streams are transmitted periodically and 2709 carry either a pre-configured payload or a payload configured during 2710 runtime. 2712 Some industrial applications require time synchronization at the end 2713 nodes. For such time-coordinated PLCs, accuracy of 1 microsecond is 2714 required. Even in the case of "non-time-coordinated" PLCs time sync 2715 may be needed e.g. for timestamping of sensor data. 2717 Industrial network scenarios require advanced security solutions. 2718 Many of the current industrial production networks are physically 2719 separated. Preventing critical flows from be leaked outside a domain 2720 is handled today by filtering policies that are typically enforced in 2721 firewalls. 2723 7.2.1. Transport Parameters 2725 The Cycle Time defines the frequency of message(s) between industrial 2726 actors. The Cycle Time is application dependent, in the range of 1ms 2727 - 100ms for critical control/data streams. 2729 Because industrial applications assume deterministic transport for 2730 critical Control-Data-Stream parameters (instead of defining latency 2731 and delay variation parameters) it is sufficient to fulfill the upper 2732 bound of latency (maximum latency). The underlying networking 2733 infrastructure must ensure a maximum end-to-end delivery time of 2734 messages in the range of 100 microseconds to 50 milliseconds 2735 depending on the control loop application. 2737 The bandwidth requirements of control/data streams are usually 2738 calculated directly from the bytes-per-cycle parameter of the control 2739 loop. For PLC-to-PLC communication one can expect 2 - 32 streams 2740 with packet size in the range of 100 - 700 bytes. For S-PLC to PLCs 2741 the number of streams is higher - up to 256 streams. Usually no more 2742 than 20% of available bandwidth is used for critical control/data 2743 streams. In today's networks 1Gbps links are commonly used. 2745 Most PLC control loops are rather tolerant of packet loss, however 2746 critical control/data streams accept no more than 1 packet loss per 2747 consecutive communication cycle (i.e. if a packet gets lost in cycle 2748 "n", then the next cycle ("n+1") must be lossless). After two or 2749 more consecutive packet losses the network may be considered to be 2750 "down" by the Application. 2752 As network downtime may impact the whole production system the 2753 required network availability is rather high (99,999%). 2755 Based on the above parameters we expect that some form of redundancy 2756 will be required for M2M communications, however any individual 2757 solution depends on several parameters including cycle time, delivery 2758 time, etc. 2760 7.2.2. Stream Creation and Destruction 2762 In an industrial environment, critical control/data streams are 2763 created rather infrequently, on the order of ~10 times per day / week 2764 / month. Most of these critical control/data streams get created at 2765 machine startup, however flexibility is also needed during runtime, 2766 for example when adding or removing a machine. Going forward as 2767 production systems become more flexible, we expect a significant 2768 increase in the rate at which streams are created, changed and 2769 destroyed. 2771 7.3. Industrial M2M Future 2773 We would like to see a converged IP-standards-based network with 2774 deterministic properties that can satisfy the timing, security and 2775 reliability constraints described above. Today's proprietary 2776 networks could then be interfaced to such a network via gateways or, 2777 in the case of new installations, devices could be connected directly 2778 to the converged network. 2780 For this use case we expect time synchronization accuracy on the 2781 order of 1us. 2783 7.4. Industrial M2M Asks 2785 o Converged IP-based network 2787 o Deterministic behavior (bounded latency and jitter ) 2789 o High availability (presumably through redundancy) (99.999 %) 2791 o Low message delivery time (100us - 50ms) 2793 o Low packet loss (burstless, 0.1-1 %) 2795 o Security (e.g. prevent critical flows from being leaked between 2796 physically separated networks) 2798 8. Mining Industry 2800 8.1. Use Case Description 2802 The mining industry is highly dependent on networks to monitor and 2803 control their systems both in open-pit and underground extraction, 2804 transport and refining processes. In order to reduce risks and 2805 increase operational efficiency in mining operations, a number of 2806 processes have migrated the operators from the extraction site to 2807 remote control and monitoring. 2809 In the case of open pit mining, autonomous trucks are used to 2810 transport the raw materials from the open pit to the refining factory 2811 where the final product (e.g. Copper) is obtained. Although the 2812 operation is autonomous, the tracks are remotely monitored from a 2813 central facility. 2815 In pit mines, the monitoring of the tailings or mine dumps is 2816 critical in order to avoid any environmental pollution. In the past, 2817 monitoring has been conducted through manual inspection of pre- 2818 installed dataloggers. Cabling is not usually exploited in such 2819 scenarios due to the cost and complex deployment requirements. 2820 Currently, wireless technologies are being employed to monitor these 2821 cases permanently. Slopes are also monitored in order to anticipate 2822 possible mine collapse. Due to the unstable terrain, cable 2823 maintenance is costly and complex and hence wireless technologies are 2824 employed. 2826 In the underground monitoring case, autonomous vehicles with 2827 extraction tools travel autonomously through the tunnels, but their 2828 operational tasks (such as excavation, stone breaking and transport) 2829 are controlled remotely from a central facility. This generates 2830 video and feedback upstream traffic plus downstream actuator control 2831 traffic. 2833 8.2. Mining Industry Today 2835 Currently the mining industry uses a packet switched architecture 2836 supported by high speed ethernet. However in order to achieve the 2837 delay and packet loss requirements the network bandwidth is 2838 overestimated, thus providing very low efficiency in terms of 2839 resource usage. 2841 QoS is implemented at the Routers to separate video, management, 2842 monitoring and process control traffic for each stream. 2844 Since mobility is involved in this process, the connection between 2845 the backbone and the mobile devices (e.g. trucks, trains and 2846 excavators) is solved using a wireless link. These links are based 2847 on 802.11 for open-pit mining and leaky feeder for underground 2848 mining. 2850 Lately in pit mines the use of LPWAN technologies has been extended: 2851 Tailings, slopes and mine dumps are monitored by battery-powered 2852 dataloggers that make use of robust long range radio technologies. 2853 Reliability is usually ensured through retransmissions at L2. 2854 Gateways or concentrators act as bridges forwarding the data to the 2855 backbone ethernet network. Deterministic requirements are biased 2856 towards reliability rather than latency as events are slowly 2857 triggered or can be anticipated in advance. 2859 At the mineral processing stage, conveyor belts and refining 2860 processes are controlled by a SCADA system, which provides the in- 2861 factory delay-constrained networking requirements. 2863 Voice communications are currently served by a redundant trunking 2864 infrastructure, independent from current data networks. 2866 8.3. Mining Industry Future 2868 Mining operations and management are currently converging towards a 2869 combination of autonomous operation and teleoperation of transport 2870 and extraction machines. This means that video, audio, monitoring 2871 and process control traffic will increase dramatically. Ideally, all 2872 activities on the mine will rely on network infrastructure. 2874 Wireless for open-pit mining is already a reality with LPWAN 2875 technologies and it is expected to evolve to more advanced LPWAN 2876 technologies such as those based on LTE to increase last hop 2877 reliability or novel LPWAN flavours with deterministic access. 2879 One area in which DetNet can improve this use case is in the wired 2880 networks that make up the "backbone network" of the system, which 2881 connect together many wireless access points (APs). The mobile 2882 machines (which are connected to the network via wireless) transition 2883 from one AP to the next as they move about. A deterministic, 2884 reliable, low latency backbone can enable these transitions to be 2885 more reliable. 2887 Connections which extend all the way from the base stations to the 2888 machinery via a mix of wired and wireless hops would also be 2889 beneficial, for example to improve remote control responsiveness of 2890 digging machines. However to guarantee deterministic performance of 2891 a DetNet, the end-to-end underlying network must be deterministic. 2892 Thus for this use case if a deterministic wireless transport is 2893 integrated with a wire-based DetNet network, it could create the 2894 desired wired plus wireless end-to-end deterministic network. 2896 8.4. Mining Industry Asks 2898 o Improved bandwidth efficiency 2900 o Very low delay to enable machine teleoperation 2902 o Dedicated bandwidth usage for high resolution video streams 2904 o Predictable delay to enable realtime monitoring 2906 o Potential to construct a unified DetNet network over a combination 2907 of wired and deterministic wireless links 2909 9. Private Blockchain 2911 9.1. Use Case Description 2913 Blockchain was created with bitcoin, as a 'public' blockchain on the 2914 open Internet, however blockchain has also spread far beyond its 2915 original host into various industries such as smart manufacturing, 2916 logistics, security, legal rights and others. In these industries 2917 blockchain runs in designated and carefully managed network in which 2918 deterministic networking requirements could be addressed by Detnet. 2919 Such implementations are referred to as 'private' blockchain. 2921 The sole distinction between public and private blockchain is related 2922 to who is allowed to participate in the network, execute the 2923 consensus protocol and maintain the shared ledger. 2925 Today's networks treat the traffic from blockchain on a best-effort 2926 basis, but blockchain operation could be made much more efficient if 2927 deterministic networking service were available to minimize latency 2928 and packet loss in the network. 2930 9.1.1. Blockchain Operation 2932 A 'block' runs as a container of a batch of primary items such as 2933 transactions, property records etc. The blocks are chained in such a 2934 way that the hash of the previous block works as the pointer header 2935 of the new block, where confirmation of each block requires a 2936 consensus mechanism. When an item arrives at a blockchain node, the 2937 latter broadcasts this item to the rest of nodes which receive and 2938 verify it and put it in the ongoing block. Block confirmation 2939 process begins as the amount of items reaches the predefined block 2940 capacity, and the node broadcasts its proved block to the rest of 2941 nodes to be verified and chained. 2943 9.1.2. Blockchain Network Architecture 2945 Blockchain node communication and coordination is achieved mainly 2946 through frequent point to multi-point communication, however 2947 persistent point-to-point connections are used to transport both the 2948 items and the blocks to the other nodes. 2950 When a node initiates, it first requests the other nodes' address 2951 from a specific entity such as DNS, then it creates persistent 2952 connections each of with other nodes. If node A confirms an item, it 2953 sends the item to the other nodes via the persistent connections. 2955 As a new block in a node completes and gets proved among the nodes, 2956 it starts propagating this block towards its neighbor nodes. Assume 2957 node A receives a block, it sends invite message after verification 2958 to its neighbor B, B checks if the designated block is available, it 2959 responds get message to A if it is unavailable, and A send the 2960 complete block to B. B repeats the process as A to start the next 2961 round of block propagation. 2963 The challenge of blockchain network operation is not overall data 2964 rates, since the volume from both block and item stays between 2965 hundreds of bytes to a couple of mega bytes per second, but is in 2966 transporting the blocks with minimum latency to maximize efficiency 2967 of the blockchain consensus process. 2969 9.1.3. Security Considerations 2971 Security is crucial to blockchain applications, and todayt blockchain 2972 addresses its security issues mainly at the application level, where 2973 cryptography as well as hash-based consensus play a leading role 2974 preventing both double-spending and malicious service attack. 2975 However, there is concern that in the proposed use case of a private 2976 blockchain network which is dependent on deterministic properties, 2977 the network could be vulnerable to delays and other specific attacks 2978 against determinism which could interrupt service. 2980 9.2. Private Blockchain Today 2982 Today private blockchain runs in L2 or L3 VPN, in general without 2983 guaranteed determinism. The industry players are starting to realize 2984 that improving determinism in their blockchain networks could improve 2985 the performance of their service, but as of today these goals are not 2986 being met. 2988 9.3. Private Blockchain Future 2990 Blockchain system performance can be greatly improved through 2991 deterministic networking service primarily because it would 2992 accelerate the consensus process. It would be valuable to be able to 2993 design a private blockchain network with the following properties: 2995 o Transport of point to multi-point traffic in a coordinated network 2996 architecture rather than at the application layer (which typically 2997 uses point-to-point connections) 2999 o Guaranteed transport latency 3001 o Reduced packet loss (to the point where packet retransmission- 3002 incurred delay would be negligible.) 3004 9.4. Private Blockchain Asks 3006 o Layer 2 and Layer 3 multicast of blockchain traffic 3008 o Item and block delivery with bounded, low latency and negligible 3009 packet loss 3011 o Coexistence in a single network of blockchain and IT traffic. 3013 o Ability to scale the network by distributing the centralized 3014 control of the network across multiple control entities. 3016 10. Network Slicing 3018 10.1. Use Case Description 3020 Network Slicing divides one physical network infrastructure into 3021 multiple logical networks. Each slice, corresponding to a logical 3022 network, uses resources and network functions independently from each 3023 other. Network Slicing provides flexibility of resource allocation 3024 and service quality customization. 3026 Future services will demand network performance with a wide variety 3027 of characteristics such as high data rate, low latency, low loss 3028 rate, security and many other parameters. Ideally every service 3029 would have its own physical network satisfying its particular 3030 performance requirements, however that would be prohibitively 3031 expensive. Network Slicing can provide a customized slice for a 3032 single service, and multiple slices can share the same physical 3033 network. This method can optimize the performance for the service at 3034 lower cost, and the flexibility of setting up and release the slices 3035 also allows the user to allocate the network resources dynamically. 3037 Unlike the other use cases presented here, Network Slicing is not a 3038 specific application that depends on specific deterministic 3039 properties; rather it is introduced as an area of networking to which 3040 DetNet might be applicable. 3042 10.2. DetNet Applied to Network Slicing 3044 10.2.1. Resource Isolation Across Slices 3046 One of the requirements discussed for Network Slicing is the "hard" 3047 separation of various users' deterministic performance. That is, it 3048 should be impossible for activity, lack of activity, or changes in 3049 activity of one or more users to have any appreciable effect on the 3050 deterministic performance parameters of any other slices. Typical 3051 techniques used today, which share a physical network among users, do 3052 not offer this level of isolation. DetNet can supply point-to-point 3053 or point-to-multipoint paths that offer bandwidth and latency 3054 guarantees to a user that cannot be affected by other users' data 3055 traffic. Thus DetNet is a powerful tool when latency and reliability 3056 are required in Network Slicing. 3058 10.2.2. Deterministic Services Within Slices 3060 Slices may need to provide services with DetNet-type performance 3061 guarantees, however we note that a system can be implemented to 3062 provide such services in more than one way. For example the slice 3063 itself might be implemented using DetNet, and thus the slice can 3064 provide service guarantees and isolation to its users without any 3065 particular DetNet awareness on the part of the users' applications. 3066 Alternatively, a "non-DetNet-aware" slice may host an application 3067 that itself implements DetNet services and thus can enjoy similar 3068 service guarantees. 3070 10.3. A Network Slicing Use Case Example - 5G Bearer Network 3072 Network Slicing is a core feature of 5G defined in 3GPP, which is 3073 currently under development. A network slice in a mobile network is 3074 a complete logical network including Radio Access Network (RAN) and 3075 Core Network (CN). It provides telecommunication services and 3076 network capabilities, which may vary from slice to slice. A 5G 3077 bearer network is a typical use case of Network Slicing; for example 3078 consider three 5G service scenarios: eMMB, URLLC, and mMTC. 3080 o eMBB (Enhanced Mobile Broadband) focuses on services characterized 3081 by high data rates, such as high definition videos, virtual 3082 reality, augmented reality, and fixed mobile convergence. 3084 o URLLC (Ultra-Reliable and Low Latency Communications) focuses on 3085 latency-sensitive services, such as self-driving vehicles, remote 3086 surgery, or drone control. 3088 o mMTC (massive Machine Type Communications) focuses on services 3089 that have high requirements for connection density, such as those 3090 typical for smart city and smart agriculture use cases. 3092 A 5G bearer network could use DetNet to provide hard resource 3093 isolation across slices and within the slice. For example consider 3094 Slice-A and Slice-B, with DetNet used to transit services URLLC-A and 3095 URLLC-B over them. Without DetNet, URLLC-A and URLLC-B would compete 3096 for bandwidth resource, and latency and reliability would not be 3097 guaranteed. With DetNet, URLLC-A and URLLC-B have separate bandwidth 3098 reservation and there is no resource conflict between them, as though 3099 they were in different logical networks. 3101 10.4. Non-5G Applications of Network Slicing 3103 Although operation of services not related to 5G is not part of the 3104 5G Network Slicing definition and scope, Network Slicing is likely to 3105 become a preferred approach to providing various services across a 3106 shared physical infrastructure. Examples include providing 3107 electrical utilities services and pro audio services via slices. Use 3108 cases like these could become more common once the work for the 5G 3109 core network evolves to include wired as well as wireless access. 3111 10.5. Limitations of DetNet in Network Slicing 3113 DetNet cannot cover every Network Slicing use case. One issue is 3114 that DetNet is a point-to-point or point-to-multipoint technology, 3115 however Network Slicing ultimately needs multi-point to multi-point 3116 guarantees. Another issue is that the number of flows that can be 3117 carried by DetNet is limited by DetNet scalability; flow aggregation 3118 and queuing management modification may help address this. 3119 Additional work and discussion are needed to address these topics. 3121 10.6. Network Slicing Today and Future 3123 Network Slicing has the promise to satisfy many requirements of 3124 future network deployment scenarios, but it is still a collection of 3125 ideas and analysis, without a specific technical solution. DetNet is 3126 one of various technologies that have potential to be used in Network 3127 Slicing, along with for example Flex-E and Segment Routing. For more 3128 information please see the IETF99 Network Slicing BOF session agenda 3129 and materials. 3131 10.7. Network Slicing Asks 3133 o Isolation from other flows through Queuing Management 3135 o Service Quality Customization and Guarantee 3137 o Security 3139 11. Use Case Common Themes 3141 This section summarizes the expected properties of a DetNet network, 3142 based on the use cases as described in this draft. 3144 11.1. Unified, standards-based network 3146 11.1.1. Extensions to Ethernet 3148 A DetNet network is not "a new kind of network" - it based on 3149 extensions to existing Ethernet standards, including elements of IEEE 3150 802.1 AVB/TSN and related standards. Presumably it will be possible 3151 to run DetNet over other underlying transports besides Ethernet, but 3152 Ethernet is explicitly supported. 3154 11.1.2. Centrally Administered 3156 In general a DetNet network is not expected to be "plug and play" - 3157 it is expected that there is some centralized network configuration 3158 and control system. Such a system may be in a single central 3159 location, or it maybe distributed across multiple control entities 3160 that function together as a unified control system for the network. 3161 However, the ability to "hot swap" components (e.g. due to 3162 malfunction) is similar enough to "plug and play" that this kind of 3163 behavior may be expected in DetNet networks, depending on the 3164 implementation. 3166 11.1.3. Standardized Data Flow Information Models 3168 Data Flow Information Models to be used with DetNet networks are to 3169 be specified by DetNet. 3171 11.1.4. L2 and L3 Integration 3173 A DetNet network is intended to integrate between Layer 2 (bridged) 3174 network(s) (e.g. AVB/TSN LAN) and Layer 3 (routed) network(s) (e.g. 3175 using IP-based protocols). One example of this is "making AVB/TSN- 3176 type deterministic performance available from Layer 3 applications, 3177 e.g. using RTP". Another example is "connecting two AVB/TSN LANs 3178 ("islands") together through a standard router". 3180 11.1.5. Consideration for IPv4 3182 This Use Cases draft explicitly does not specify any particular 3183 implementation or protocol, however it has been observed that various 3184 of the use cases described (and their associated industries) are 3185 explicitly based on IPv4 (as opposed to IPv6) and it is not 3186 considered practical to expect them to migrate to IPv6 in order to 3187 use DetNet. Thus the expectation is that even if not every feature 3188 of DetNet is available in an IPv4 context, at least some of the 3189 significant benefits (such as guaranteed end-to-end delivery and low 3190 latency) are expected to be available. 3192 11.1.6. Guaranteed End-to-End Delivery 3194 Packets sent over DetNet are guaranteed not to be dropped by the 3195 network due to congestion. (Packets may however be dropped for 3196 intended reasons, e.g. per security measures). 3198 11.1.7. Replacement for Multiple Proprietary Deterministic Networks 3200 There are many proprietary non-interoperable deterministic Ethernet- 3201 based networks currently available; DetNet is intended to provide an 3202 open-standards-based alternative to such networks. 3204 11.1.8. Mix of Deterministic and Best-Effort Traffic 3206 DetNet is intended to support coexistance of time-sensitive 3207 operational (OT) traffic and information (IT) traffic on the same 3208 ("unified") network. 3210 11.1.9. Unused Reserved BW to be Available to Best Effort Traffic 3212 If bandwidth reservations are made for a stream but the associated 3213 bandwidth is not used at any point in time, that bandwidth is made 3214 available on the network for best-effort traffic. If the owner of 3215 the reserved stream then starts transmitting again, the bandwidth is 3216 no longer available for best-effort traffic, on a moment-to-moment 3217 basis. Note that such "temporarily available" bandwidth is not 3218 available for time-sensitive traffic, which must have its own 3219 reservation. 3221 11.1.10. Lower Cost, Multi-Vendor Solutions 3223 The DetNet network specifications are intended to enable an ecosystem 3224 in which multiple vendors can create interoperable products, thus 3225 promoting device diversity and potentially higher numbers of each 3226 device manufactured, promoting cost reduction and cost competition 3227 among vendors. The intent is that DetNet networks should be able to 3228 be created at lower cost and with greater diversity of available 3229 devices than existing proprietary networks. 3231 11.2. Scalable Size 3233 DetNet networks range in size from very small, e.g. inside a single 3234 industrial machine, to very large, for example a Utility Grid network 3235 spanning a whole country, and involving many "hops" over various 3236 kinds of links for example radio repeaters, microwave linkes, fiber 3237 optic links, etc.. However recall that the scope of DetNet is 3238 confined to networks that are centrally administered, and explicitly 3239 excludes unbounded decentralized networks such as the Internet. 3241 11.3. Scalable Timing Parameters and Accuracy 3243 11.3.1. Bounded Latency 3245 The DetNet Data Flow Information Model is expected to provide means 3246 to configure the network that include parameters for querying network 3247 path latency, requesting bounded latency for a given stream, 3248 requesting worst case maximum and/or minimum latency for a given path 3249 or stream, and so on. It is an expected case that the network may 3250 not be able to provide a given requested service level, and if so the 3251 network control system should reply that the requested services is 3252 not available (as opposed to accepting the parameter but then not 3253 delivering the desired behavior). 3255 11.3.2. Low Latency 3257 Applications may require "extremely low latency" however depending on 3258 the application these may mean very different latency values; for 3259 example "low latency" across a Utility grid network is on a different 3260 time scale than "low latency" in a motor control loop in a small 3261 machine. The intent is that the mechanisms for specifying desired 3262 latency include wide ranges, and that architecturally there is 3263 nothing to prevent arbirtrarily low latencies from being implemented 3264 in a given network. 3266 11.3.3. Symmetrical Path Delays 3268 Some applications would like to specify that the transit delay time 3269 values be equal for both the transmit and return paths. 3271 11.4. High Reliability and Availability 3273 Reliablity is of critical importance to many DetNet applications, in 3274 which consequences of failure can be extraordinarily high in terms of 3275 cost and even human life. DetNet based systems are expected to be 3276 implemented with essentially arbitrarily high availability (for 3277 example 99.9999% up time, or even 12 nines). The intent is that the 3278 DetNet designs should not make any assumptions about the level of 3279 reliability and availability that may be required of a given system, 3280 and should define parameters for communicating these kinds of metrics 3281 within the network. 3283 A strategy used by DetNet for providing such extraordinarily high 3284 levels of reliability is to provide redundant paths that can be 3285 seamlessly switched between, while maintaining the required 3286 performance of that system. 3288 11.5. Security 3290 Security is of critical importance to many DetNet applications. A 3291 DetNet network must be able to be made secure against devices 3292 failures, attackers, misbehaving devices, and so on. In a DetNet 3293 network the data traffic is expected to be be time-sensitive, thus in 3294 addition to arriving with the data content as intended, the data must 3295 also arrive at the expected time. This may present "new" security 3296 challenges to implementers, and must be addressed accordingly. There 3297 are other security implications, including (but not limited to) the 3298 change in attack surface presented by packet replication and 3299 elimination. 3301 11.6. Deterministic Flows 3303 Reserved bandwidth data flows must be isolated from each other and 3304 from best-effort traffic, so that even if the network is saturated 3305 with best-effort (and/or reserved bandwidth) traffic, the configured 3306 flows are not adversely affected. 3308 12. Use Cases Explicitly Out of Scope for DetNet 3310 This section contains use case text that has been determined to be 3311 outside of the scope of the present DetNet work. 3313 12.1. DetNet Scope Limitations 3315 The scope of DetNet is deliberately limited to specific use cases 3316 that are consistent with the WG charter, subject to the 3317 interpretation of the WG. At the time the DetNet Use Cases were 3318 solicited and provided by the authors the scope of DetNet was not 3319 clearly defined, and as that clarity has emerged, certain of the use 3320 cases have been determined to be outside the scope of the present 3321 DetNet work. Such text has been moved into this section to clarify 3322 that these use cases will not be supported by the DetNet work. 3324 The text in this section was moved here based on the following 3325 "exclusion" principles. Or, as an alternative to moving all such 3326 text to this section, some draft text has been modified in situ to 3327 reflect these same principles. 3329 The following principles have been established to clarify the scope 3330 of the present DetNet work. 3332 o The scope of network addressed by DetNet is limited to networks 3333 that can be centrally controlled, i.e. an "enterprise" aka 3334 "corporate" network. This explicitly excludes "the open 3335 Internet". 3337 o Maintaining synchronized time across a DetNet network is crucial 3338 to its operation, however DetNet assumes that time is to be 3339 maintained using other means, for example (but not limited to) 3340 Precision Time Protocol ([IEEE1588]). A use case may state the 3341 accuracy and reliability that it expects from the DetNet network 3342 as part of a whole system, however it is understood that such 3343 timing properties are not guaranteed by DetNet itself. It is 3344 currently an open question as to whether DetNet protocols will 3345 include a way for an application to communicate such timing 3346 expectations to the network, and if so whether they would be 3347 expected to materially affect the performance they would receive 3348 from the network as a result. 3350 12.2. Internet-based Applications 3352 12.2.1. Use Case Description 3354 There are many applications that communicate across the open Internet 3355 that could benefit from guaranteed delivery and bounded latency. The 3356 following are some representative examples. 3358 12.2.1.1. Media Content Delivery 3360 Media content delivery continues to be an important use of the 3361 Internet, yet users often experience poor quality audio and video due 3362 to the delay and jitter inherent in today's Internet. 3364 12.2.1.2. Online Gaming 3366 Online gaming is a significant part of the gaming market, however 3367 latency can degrade the end user experience. For example "First 3368 Person Shooter" (FPS) games are highly delay-sensitive. 3370 12.2.1.3. Virtual Reality 3372 Virtual reality (VR) has many commercial applications including real 3373 estate presentations, remote medical procedures, and so on. Low 3374 latency is critical to interacting with the virtual world because 3375 perceptual delays can cause motion sickness. 3377 12.2.2. Internet-Based Applications Today 3379 Internet service today is by definition "best effort", with no 3380 guarantees on delivery or bandwidth. 3382 12.2.3. Internet-Based Applications Future 3384 We imagine an Internet from which we will be able to play a video 3385 without glitches and play games without lag. 3387 For online gaming, the maximum round-trip delay can be 100ms and 3388 stricter for FPS gaming which can be 10-50ms. Transport delay is the 3389 dominate part with a 5-20ms budget. 3391 For VR, 1-10ms maximum delay is needed and total network budget is 3392 1-5ms if doing remote VR. 3394 Flow identification can be used for gaming and VR, i.e. it can 3395 recognize a critical flow and provide appropriate latency bounds. 3397 12.2.4. Internet-Based Applications Asks 3399 o Unified control and management protocols to handle time-critical 3400 data flow 3402 o Application-aware flow filtering mechanism to recognize the timing 3403 critical flow without doing 5-tuple matching 3405 o Unified control plane to provide low latency service on Layer-3 3406 without changing the data plane 3408 o OAM system and protocols which can help to provide E2E-delay 3409 sensitive service provisioning 3411 12.3. Pro Audio and Video - Digital Rights Management (DRM) 3413 This section was moved here because this is considered a Link layer 3414 topic, not direct responsibility of DetNet. 3416 Digital Rights Management (DRM) is very important to the audio and 3417 video industries. Any time protected content is introduced into a 3418 network there are DRM concerns that must be maintained (see 3419 [CONTENT_PROTECTION]). Many aspects of DRM are outside the scope of 3420 network technology, however there are cases when a secure link 3421 supporting authentication and encryption is required by content 3422 owners to carry their audio or video content when it is outside their 3423 own secure environment (for example see [DCI]). 3425 As an example, two techniques are Digital Transmission Content 3426 Protection (DTCP) and High-Bandwidth Digital Content Protection 3427 (HDCP). HDCP content is not approved for retransmission within any 3428 other type of DRM, while DTCP may be retransmitted under HDCP. 3429 Therefore if the source of a stream is outside of the network and it 3430 uses HDCP protection it is only allowed to be placed on the network 3431 with that same HDCP protection. 3433 12.4. Pro Audio and Video - Link Aggregation 3435 Note: The term "Link Aggregation" is used here as defined by the text 3436 in the following paragraph, i.e. not following a more common Network 3437 Industry definition. Current WG consensus is that this item won't be 3438 directly supported by the DetNet architecture, for example because it 3439 implies guarantee of in-order delivery of packets which conflicts 3440 with the core goal of achieving the lowest possible latency. 3442 For transmitting streams that require more bandwidth than a single 3443 link in the target network can support, link aggregation is a 3444 technique for combining (aggregating) the bandwidth available on 3445 multiple physical links to create a single logical link of the 3446 required bandwidth. However, if aggregation is to be used, the 3447 network controller (or equivalent) must be able to determine the 3448 maximum latency of any path through the aggregate link. 3450 13. Contributors 3452 RFC7322 limits the number of authors listed on the front page of a 3453 draft to a maximum of 5, far fewer than the 20 individuals below who 3454 made important contributions to this draft. The editor wishes to 3455 thank and acknowledge each of the following authors for contributing 3456 text to this draft. See also Section 14. 3458 Craig Gunther (Harman International) 3459 10653 South River Front Parkway, South Jordan,UT 84095 3460 phone +1 801 568-7675, email craig.gunther@harman.com 3462 Pascal Thubert (Cisco Systems, Inc) 3463 Building D, 45 Allee des Ormes - BP1200, MOUGINS 3464 Sophia Antipolis 06254 FRANCE 3465 phone +33 497 23 26 34, email pthubert@cisco.com 3467 Patrick Wetterwald (Cisco Systems) 3468 45 Allees des Ormes, Mougins, 06250 FRANCE 3469 phone +33 4 97 23 26 36, email pwetterw@cisco.com 3471 Jean Raymond (Hydro-Quebec) 3472 1500 University, Montreal, H3A3S7, Canada 3473 phone +1 514 840 3000, email raymond.jean@hydro.qc.ca 3475 Jouni Korhonen (Broadcom Corporation) 3476 3151 Zanker Road, San Jose, 95134, CA, USA 3477 email jouni.nospam@gmail.com 3479 Yu Kaneko (Toshiba) 3480 1 Komukai-Toshiba-cho, Saiwai-ku, Kasasaki-shi, Kanagawa, Japan 3481 email yu1.kaneko@toshiba.co.jp 3483 Subir Das (Vencore Labs) 3484 150 Mount Airy Road, Basking Ridge, New Jersey, 07920, USA 3485 email sdas@appcomsci.com 3487 Balazs Varga (Ericsson) 3488 Konyves Kalman krt. 11/B, Budapest, Hungary, 1097 3489 email balazs.a.varga@ericsson.com 3491 Janos Farkas (Ericsson) 3492 Konyves Kalman krt. 11/B, Budapest, Hungary, 1097 3493 email janos.farkas@ericsson.com 3495 Franz-Josef Goetz (Siemens) 3496 Gleiwitzerstr. 555, Nurnberg, Germany, 90475 3497 email franz-josef.goetz@siemens.com 3499 Juergen Schmitt (Siemens) 3500 Gleiwitzerstr. 555, Nurnberg, Germany, 90475 3501 email juergen.jues.schmitt@siemens.com 3503 Xavier Vilajosana (Worldsensing) 3504 483 Arago, Barcelona, Catalonia, 08013, Spain 3505 email xvilajosana@worldsensing.com 3507 Toktam Mahmoodi (King's College London) 3508 Strand, London WC2R 2LS, United Kingdom 3509 email toktam.mahmoodi@kcl.ac.uk 3511 Spiros Spirou (Intracom Telecom) 3512 19.7 km Markopoulou Ave., Peania, Attiki, 19002, Greece 3513 email spiros.spirou@gmail.com 3515 Petra Vizarreta (Technical University of Munich) 3516 Maxvorstadt, ArcisstraBe 21, Munich, 80333, Germany 3517 email petra.stojsavljevic@tum.de 3519 Daniel Huang (ZTE Corporation, Inc.) 3520 No. 50 Software Avenue, Nanjing, Jiangsu, 210012, P.R. China 3521 email huang.guangping@zte.com.cn 3523 Xuesong Geng (Huawei Technologies) 3524 email gengxuesong@huawei.com 3526 Diego Dujovne (Universidad Diego Portales) 3527 email diego.dujovne@mail.udp.cl 3529 Maik Seewald (Cisco Systems) 3530 email maseewal@cisco.com 3532 14. Acknowledgments 3534 14.1. Pro Audio 3536 This section was derived from draft-gunther-detnet-proaudio-req-01. 3538 The editors would like to acknowledge the help of the following 3539 individuals and the companies they represent: 3541 Jeff Koftinoff, Meyer Sound 3543 Jouni Korhonen, Associate Technical Director, Broadcom 3545 Pascal Thubert, CTAO, Cisco 3547 Kieran Tyrrell, Sienda New Media Technologies GmbH 3549 14.2. Utility Telecom 3551 This section was derived from draft-wetterwald-detnet-utilities-reqs- 3552 02. 3554 Faramarz Maghsoodlou, Ph. D. IoT Connected Industries and Energy 3555 Practice Cisco 3557 Pascal Thubert, CTAO Cisco 3559 14.3. Building Automation Systems 3561 This section was derived from draft-bas-usecase-detnet-00. 3563 14.4. Wireless for Industrial 3565 This section was derived from draft-thubert-6tisch-4detnet-01. 3567 This specification derives from the 6TiSCH architecture, which is the 3568 result of multiple interactions, in particular during the 6TiSCH 3569 (bi)Weekly Interim call, relayed through the 6TiSCH mailing list at 3570 the IETF. 3572 The authors wish to thank: Kris Pister, Thomas Watteyne, Xavier 3573 Vilajosana, Qin Wang, Tom Phinney, Robert Assimiti, Michael 3574 Richardson, Zhuo Chen, Malisa Vucinic, Alfredo Grieco, Martin Turon, 3575 Dominique Barthel, Elvis Vogli, Guillaume Gaillard, Herman Storey, 3576 Maria Rita Palattella, Nicola Accettura, Patrick Wetterwald, Pouria 3577 Zand, Raghuram Sudhaakar, and Shitanshu Shah for their participation 3578 and various contributions. 3580 14.5. Cellular Radio 3582 This section was derived from draft-korhonen-detnet-telreq-00. 3584 14.6. Industrial M2M 3586 The authors would like to thank Feng Chen and Marcel Kiessling for 3587 their comments and suggestions. 3589 14.7. Internet Applications and CoMP 3591 This section was derived from draft-zha-detnet-use-case-00 by Yiyong 3592 Zha. 3594 This document has benefited from reviews, suggestions, comments and 3595 proposed text provided by the following members, listed in 3596 alphabetical order: Jing Huang, Junru Lin, Lehong Niu and Oilver 3597 Huang. 3599 14.8. Electrical Utilities 3601 The wind power generation use case has been extracted from the study 3602 of Wind Farms conducted within the 5GPPP Virtuwind Project. The 3603 project is funded by the European Union's Horizon 2020 research and 3604 innovation programme under grant agreement No 671648 (VirtuWind). 3606 14.9. Network Slicing 3608 This section was written by Xuesong Geng, who would like to 3609 acknowledge Norm Finn and Mach Chen for their useful comments. 3611 14.10. Mining 3613 This section was written by Diego Dujovne in conjunction with Xavier 3614 Vilasojana. 3616 14.11. Private Blockchain 3618 This section was written by Daniel Huang. 3620 15. Informative References 3622 [ACE] IETF, "Authentication and Authorization for Constrained 3623 Environments", 3624 . 3626 [Ahm14] Ahmed, M. and R. Kim, "Communication network architectures 3627 for smart-wind power farms.", Energies, p. 3900-3921. , 3628 June 2014. 3630 [bacnetip] 3631 ASHRAE, "Annex J to ANSI/ASHRAE 135-1995 - BACnet/IP", 3632 January 1999. 3634 [CCAMP] IETF, "Common Control and Measurement Plane", 3635 . 3637 [CoMP] NGMN Alliance, "RAN EVOLUTION PROJECT COMP EVALUATION AND 3638 ENHANCEMENT", NGMN Alliance NGMN_RANEV_D3_CoMP_Evaluation_ 3639 and_Enhancement_v2.0, March 2015, 3640 . 3643 [CONTENT_PROTECTION] 3644 Olsen, D., "1722a Content Protection", 2012, 3645 . 3648 [CPRI] CPRI Cooperation, "Common Public Radio Interface (CPRI); 3649 Interface Specification", CPRI Specification V6.1, July 3650 2014, . 3653 [CPRI-transp] 3654 CPRI TWG, "CPRI requirements for Ethernet Fronthaul", 3655 November 2015, 3656 . 3659 [DCI] Digital Cinema Initiatives, LLC, "DCI Specification, 3660 Version 1.2", 2012, . 3662 [DICE] IETF, "DTLS In Constrained Environments", 3663 . 3665 [EA12] Evans, P. and M. Annunziata, "Industrial Internet: Pushing 3666 the Boundaries of Minds and Machines", November 2012. 3668 [eCPRI] IEEE Standards Association, "Common Public Radio 3669 Interface, "Common Public Radio Interface: eCPRI Interface 3670 Specification V1.0", 2017, . 3672 [ESPN_DC2] 3673 Daley, D., "ESPN's DC2 Scales AVB Large", 2014, 3674 . 3677 [flnet] Japan Electrical Manufacturers Association, "JEMA 1479 - 3678 English Edition", September 2012. 3680 [Fronthaul] 3681 Chen, D. and T. Mustala, "Ethernet Fronthaul 3682 Considerations", IEEE 1904.3, February 2015, 3683 . 3686 [HART] www.hartcomm.org, "Highway Addressable remote Transducer, 3687 a group of specifications for industrial process and 3688 control devices administered by the HART Foundation". 3690 [I-D.finn-detnet-architecture] 3691 Finn, N. and P. Thubert, "Deterministic Networking 3692 Architecture", draft-finn-detnet-architecture-08 (work in 3693 progress), August 2016. 3695 [I-D.finn-detnet-problem-statement] 3696 Finn, N. and P. Thubert, "Deterministic Networking Problem 3697 Statement", draft-finn-detnet-problem-statement-05 (work 3698 in progress), March 2016. 3700 [I-D.ietf-6tisch-6top-interface] 3701 Wang, Q. and X. Vilajosana, "6TiSCH Operation Sublayer 3702 (6top) Interface", draft-ietf-6tisch-6top-interface-04 3703 (work in progress), July 2015. 3705 [I-D.ietf-6tisch-architecture] 3706 Thubert, P., "An Architecture for IPv6 over the TSCH mode 3707 of IEEE 802.15.4", draft-ietf-6tisch-architecture-14 (work 3708 in progress), April 2018. 3710 [I-D.ietf-6tisch-coap] 3711 Sudhaakar, R. and P. Zand, "6TiSCH Resource Management and 3712 Interaction using CoAP", draft-ietf-6tisch-coap-03 (work 3713 in progress), March 2015. 3715 [I-D.ietf-6tisch-terminology] 3716 Palattella, M., Thubert, P., Watteyne, T., and Q. Wang, 3717 "Terms Used in IPv6 over the TSCH mode of IEEE 802.15.4e", 3718 draft-ietf-6tisch-terminology-10 (work in progress), March 3719 2018. 3721 [I-D.ietf-ipv6-multilink-subnets] 3722 Thaler, D. and C. Huitema, "Multi-link Subnet Support in 3723 IPv6", draft-ietf-ipv6-multilink-subnets-00 (work in 3724 progress), July 2002. 3726 [I-D.ietf-mpls-residence-time] 3727 Mirsky, G., Ruffini, S., Gray, E., Drake, J., Bryant, S., 3728 and S. Vainshtein, "Residence Time Measurement in MPLS 3729 network", draft-ietf-mpls-residence-time-15 (work in 3730 progress), March 2017. 3732 [I-D.ietf-roll-rpl-industrial-applicability] 3733 Phinney, T., Thubert, P., and R. Assimiti, "RPL 3734 applicability in industrial networks", draft-ietf-roll- 3735 rpl-industrial-applicability-02 (work in progress), 3736 October 2013. 3738 [I-D.ietf-tictoc-1588overmpls] 3739 Davari, S., Oren, A., Bhatia, M., Roberts, P., and L. 3740 Montini, "Transporting Timing messages over MPLS 3741 Networks", draft-ietf-tictoc-1588overmpls-07 (work in 3742 progress), October 2015. 3744 [I-D.kh-spring-ip-ran-use-case] 3745 Khasnabish, B., hu, f., and L. Contreras, "Segment Routing 3746 in IP RAN use case", draft-kh-spring-ip-ran-use-case-02 3747 (work in progress), November 2014. 3749 [I-D.svshah-tsvwg-deterministic-forwarding] 3750 Shah, S. and P. Thubert, "Deterministic Forwarding PHB", 3751 draft-svshah-tsvwg-deterministic-forwarding-04 (work in 3752 progress), August 2015. 3754 [I-D.thubert-6lowpan-backbone-router] 3755 Thubert, P., "6LoWPAN Backbone Router", draft-thubert- 3756 6lowpan-backbone-router-03 (work in progress), February 3757 2013. 3759 [I-D.wang-6tisch-6top-sublayer] 3760 Wang, Q. and X. Vilajosana, "6TiSCH Operation Sublayer 3761 (6top)", draft-wang-6tisch-6top-sublayer-04 (work in 3762 progress), November 2015. 3764 [IEC-60870-5-104] 3765 International Electrotechnical Commission, "International 3766 Standard IEC 60870-5-104: Network access for IEC 3767 60870-5-101 using standard transport profiles", June 2006. 3769 [IEC61400] 3770 "International standard 61400-25: Communications for 3771 monitoring and control of wind power plants", June 2013. 3773 [IEC61850-90-12] 3774 TC57 WG10, IEC., "IEC 61850-90-12 TR: Communication 3775 networks and systems for power utility automation - Part 3776 90-12: Wide area network engineering guidelines", 2015. 3778 [IEC62439-3:2012] 3779 TC65, IEC., "IEC 62439-3: Industrial communication 3780 networks - High availability automation networks - Part 3: 3781 Parallel Redundancy Protocol (PRP) and High-availability 3782 Seamless Redundancy (HSR)", 2012. 3784 [IEEE1588] 3785 IEEE, "IEEE Standard for a Precision Clock Synchronization 3786 Protocol for Networked Measurement and Control Systems", 3787 IEEE Std 1588-2008, 2008, 3788 . 3791 [IEEE1646] 3792 "Communication Delivery Time Performance Requirements for 3793 Electric Power Substation Automation", IEEE Standard 3794 1646-2004 , Apr 2004. 3796 [IEEE1722] 3797 IEEE, "1722-2011 - IEEE Standard for Layer 2 Transport 3798 Protocol for Time Sensitive Applications in a Bridged 3799 Local Area Network", IEEE Std 1722-2011, 2011, 3800 . 3803 [IEEE19143] 3804 IEEE Standards Association, "P1914.3/D3.1 Draft Standard 3805 for Radio over Ethernet Encapsulations and Mappings", 3806 IEEE 1914.3, 2018, 3807 . 3809 [IEEE802.1TSNTG] 3810 IEEE Standards Association, "IEEE 802.1 Time-Sensitive 3811 Networks Task Group", March 2013, 3812 . 3814 [IEEE802154] 3815 IEEE standard for Information Technology, "IEEE std. 3816 802.15.4, Part. 15.4: Wireless Medium Access Control (MAC) 3817 and Physical Layer (PHY) Specifications for Low-Rate 3818 Wireless Personal Area Networks". 3820 [IEEE802154e] 3821 IEEE standard for Information Technology, "IEEE standard 3822 for Information Technology, IEEE std. 802.15.4, Part. 3823 15.4: Wireless Medium Access Control (MAC) and Physical 3824 Layer (PHY) Specifications for Low-Rate Wireless Personal 3825 Area Networks, June 2011 as amended by IEEE std. 3826 802.15.4e, Part. 15.4: Low-Rate Wireless Personal Area 3827 Networks (LR-WPANs) Amendment 1: MAC sublayer", April 3828 2012. 3830 [IEEE8021AS] 3831 IEEE, "Timing and Synchronizations (IEEE 802.1AS-2011)", 3832 IEEE 802.1AS-2001, 2011, 3833 . 3836 [IEEE8021CM] 3837 Farkas, J., "Time-Sensitive Networking for Fronthaul", 3838 Unapproved PAR, PAR for a New IEEE Standard; 3839 IEEE P802.1CM, April 2015, 3840 . 3843 [IEEE8021TSN] 3844 IEEE 802.1, "The charter of the TG is to provide the 3845 specifications that will allow time-synchronized low 3846 latency streaming services through 802 networks.", 2016, 3847 . 3849 [IETFDetNet] 3850 IETF, "Charter for IETF DetNet Working Group", 2015, 3851 . 3853 [ISA100] ISA/ANSI, "ISA100, Wireless Systems for Automation", 3854 . 3856 [ISA100.11a] 3857 ISA/ANSI, "Wireless Systems for Industrial Automation: 3858 Process Control and Related Applications - ISA100.11a-2011 3859 - IEC 62734", 2011, . 3862 [ISO7240-16] 3863 ISO, "ISO 7240-16:2007 Fire detection and alarm systems -- 3864 Part 16: Sound system control and indicating equipment", 3865 2007, . 3868 [knx] KNX Association, "ISO/IEC 14543-3 - KNX", November 2006. 3870 [lontalk] ECHELON, "LonTalk(R) Protocol Specification Version 3.0", 3871 1994. 3873 [LTE-Latency] 3874 Johnston, S., "LTE Latency: How does it compare to other 3875 technologies", March 2014, 3876 . 3879 [MEF22.1.1] 3880 MEF, "Mobile Backhaul Phase 2 Amendment 1 -- Small Cells", 3881 MEF 22.1.1, July 2014, 3882 . 3885 [MEF8] MEF, "Implementation Agreement for the Emulation of PDH 3886 Circuits over Metro Ethernet Networks", MEF 8, October 3887 2004, 3888 . 3891 [METIS] METIS, "Scenarios, requirements and KPIs for 5G mobile and 3892 wireless system", ICT-317669-METIS/D1.1 ICT- 3893 317669-METIS/D1.1, April 2013, . 3896 [modbus] Modbus Organization, "MODBUS APPLICATION PROTOCOL 3897 SPECIFICATION V1.1b", December 2006. 3899 [MODBUS] Modbus Organization, Inc., "MODBUS Application Protocol 3900 Specification", Apr 2012. 3902 [net5G] Ericsson, "5G Radio Access, Challenges for 2020 and 3903 Beyond", Ericsson white paper wp-5g, June 2013, 3904 . 3906 [NGMN] NGMN Alliance, "5G White Paper", NGMN 5G White Paper v1.0, 3907 February 2015, . 3910 [NGMN-fronth] 3911 NGMN Alliance, "Fronthaul Requirements for C-RAN", March 3912 2015, . 3915 [OPCXML] OPC Foundation, "OPC XML-Data Access Specification", Dec 3916 2004. 3918 [PCE] IETF, "Path Computation Element", 3919 . 3921 [profibus] 3922 IEC, "IEC 61158 Type 3 - Profibus DP", January 2001. 3924 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 3925 Requirement Levels", BCP 14, RFC 2119, 3926 DOI 10.17487/RFC2119, March 1997, 3927 . 3929 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 3930 (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460, 3931 December 1998, . 3933 [RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black, 3934 "Definition of the Differentiated Services Field (DS 3935 Field) in the IPv4 and IPv6 Headers", RFC 2474, 3936 DOI 10.17487/RFC2474, December 1998, 3937 . 3939 [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol 3940 Label Switching Architecture", RFC 3031, 3941 DOI 10.17487/RFC3031, January 2001, 3942 . 3944 [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., 3945 and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP 3946 Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001, 3947 . 3949 [RFC3393] Demichelis, C. and P. Chimento, "IP Packet Delay Variation 3950 Metric for IP Performance Metrics (IPPM)", RFC 3393, 3951 DOI 10.17487/RFC3393, November 2002, 3952 . 3954 [RFC3411] Harrington, D., Presuhn, R., and B. Wijnen, "An 3955 Architecture for Describing Simple Network Management 3956 Protocol (SNMP) Management Frameworks", STD 62, RFC 3411, 3957 DOI 10.17487/RFC3411, December 2002, 3958 . 3960 [RFC3444] Pras, A. and J. Schoenwaelder, "On the Difference between 3961 Information Models and Data Models", RFC 3444, 3962 DOI 10.17487/RFC3444, January 2003, 3963 . 3965 [RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)", 3966 RFC 3972, DOI 10.17487/RFC3972, March 2005, 3967 . 3969 [RFC3985] Bryant, S., Ed. and P. Pate, Ed., "Pseudo Wire Emulation 3970 Edge-to-Edge (PWE3) Architecture", RFC 3985, 3971 DOI 10.17487/RFC3985, March 2005, 3972 . 3974 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 3975 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 3976 2006, . 3978 [RFC4553] Vainshtein, A., Ed. and YJ. Stein, Ed., "Structure- 3979 Agnostic Time Division Multiplexing (TDM) over Packet 3980 (SAToP)", RFC 4553, DOI 10.17487/RFC4553, June 2006, 3981 . 3983 [RFC4903] Thaler, D., "Multi-Link Subnet Issues", RFC 4903, 3984 DOI 10.17487/RFC4903, June 2007, 3985 . 3987 [RFC4919] Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6 3988 over Low-Power Wireless Personal Area Networks (6LoWPANs): 3989 Overview, Assumptions, Problem Statement, and Goals", 3990 RFC 4919, DOI 10.17487/RFC4919, August 2007, 3991 . 3993 [RFC5086] Vainshtein, A., Ed., Sasson, I., Metz, E., Frost, T., and 3994 P. Pate, "Structure-Aware Time Division Multiplexed (TDM) 3995 Circuit Emulation Service over Packet Switched Network 3996 (CESoPSN)", RFC 5086, DOI 10.17487/RFC5086, December 2007, 3997 . 3999 [RFC5087] Stein, Y(J)., Shashoua, R., Insler, R., and M. Anavi, 4000 "Time Division Multiplexing over IP (TDMoIP)", RFC 5087, 4001 DOI 10.17487/RFC5087, December 2007, 4002 . 4004 [RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6 4005 Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, 4006 DOI 10.17487/RFC6282, September 2011, 4007 . 4009 [RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J., 4010 Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur, 4011 JP., and R. Alexander, "RPL: IPv6 Routing Protocol for 4012 Low-Power and Lossy Networks", RFC 6550, 4013 DOI 10.17487/RFC6550, March 2012, 4014 . 4016 [RFC6551] Vasseur, JP., Ed., Kim, M., Ed., Pister, K., Dejean, N., 4017 and D. Barthel, "Routing Metrics Used for Path Calculation 4018 in Low-Power and Lossy Networks", RFC 6551, 4019 DOI 10.17487/RFC6551, March 2012, 4020 . 4022 [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. 4023 Bormann, "Neighbor Discovery Optimization for IPv6 over 4024 Low-Power Wireless Personal Area Networks (6LoWPANs)", 4025 RFC 6775, DOI 10.17487/RFC6775, November 2012, 4026 . 4028 [RFC7554] Watteyne, T., Ed., Palattella, M., and L. Grieco, "Using 4029 IEEE 802.15.4e Time-Slotted Channel Hopping (TSCH) in the 4030 Internet of Things (IoT): Problem Statement", RFC 7554, 4031 DOI 10.17487/RFC7554, May 2015, 4032 . 4034 [Spe09] Sperotto, A., Sadre, R., Vliet, F., and A. Pras, "A First 4035 Look into SCADA Network Traffic", IP Operations and 4036 Management, p. 518-521. , June 2009. 4038 [SRP_LATENCY] 4039 Gunther, C., "Specifying SRP Latency", 2014, 4040 . 4043 [STUDIO_IP] 4044 Mace, G., "IP Networked Studio Infrastructure for 4045 Synchronized & Real-Time Multimedia Transmissions", 2007, 4046 . 4049 [SyncE] ITU-T, "G.8261 : Timing and synchronization aspects in 4050 packet networks", Recommendation G.8261, August 2013, 4051 . 4053 [TEAS] IETF, "Traffic Engineering Architecture and Signaling", 4054 . 4056 [TR38801] IEEE Standards Association, "3GPP TR 38.801, Technical 4057 Specification Group Radio Access Network; Study on new 4058 radio access technology: Radio access architecture and 4059 interfaces (Release 14)", 2017, 4060 . 4063 [TS23401] 3GPP, "General Packet Radio Service (GPRS) enhancements 4064 for Evolved Universal Terrestrial Radio Access Network 4065 (E-UTRAN) access", 3GPP TS 23.401 10.10.0, March 2013. 4067 [TS25104] 3GPP, "Base Station (BS) radio transmission and reception 4068 (FDD)", 3GPP TS 25.104 3.14.0, March 2007. 4070 [TS36104] 3GPP, "Evolved Universal Terrestrial Radio Access 4071 (E-UTRA); Base Station (BS) radio transmission and 4072 reception", 3GPP TS 36.104 10.11.0, July 2013. 4074 [TS36133] 3GPP, "Evolved Universal Terrestrial Radio Access 4075 (E-UTRA); Requirements for support of radio resource 4076 management", 3GPP TS 36.133 12.7.0, April 2015. 4078 [TS36211] 3GPP, "Evolved Universal Terrestrial Radio Access 4079 (E-UTRA); Physical channels and modulation", 3GPP 4080 TS 36.211 10.7.0, March 2013. 4082 [TS36300] 3GPP, "Evolved Universal Terrestrial Radio Access (E-UTRA) 4083 and Evolved Universal Terrestrial Radio Access Network 4084 (E-UTRAN); Overall description; Stage 2", 3GPP TS 36.300 4085 10.11.0, September 2013. 4087 [TSNTG] IEEE Standards Association, "IEEE 802.1 Time-Sensitive 4088 Networks Task Group", 2013, 4089 . 4091 [UHD-video] 4092 Holub, P., "Ultra-High Definition Videos and Their 4093 Applications over the Network", The 7th International 4094 Symposium on VICTORIES Project PetrHolub_presentation, 4095 October 2014, . 4098 [WirelessHART] 4099 www.hartcomm.org, "Industrial Communication Networks - 4100 Wireless Communication Network and Communication Profiles 4101 - WirelessHART - IEC 62591", 2010. 4103 Author's Address 4105 Ethan Grossman (editor) 4106 Dolby Laboratories, Inc. 4107 1275 Market Street 4108 San Francisco, CA 94103 4109 USA 4111 Phone: +1 415 645 4726 4112 Email: ethan.grossman@dolby.com 4113 URI: http://www.dolby.com