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Checking references for intended status: Informational ---------------------------------------------------------------------------- == Outdated reference: A later version (-12) exists of draft-ietf-rtgwg-enterprise-pa-multihoming-00 == Outdated reference: A later version (-15) exists of draft-ietf-spring-segment-routing-11 Summary: 0 errors (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Spring J. Brzozowski 3 Internet-Draft J. Leddy 4 Intended status: Informational Comcast 5 Expires: December 15, 2017 C. Filsfils 6 R. Maglione, Ed. 7 M. Townsley 8 Cisco Systems 9 June 13, 2017 11 IPv6 SPRING Use Cases 12 draft-ietf-spring-ipv6-use-cases-11 14 Abstract 16 The Source Packet Routing in Networking (SPRING) architecture 17 describes how Segment Routing can be used to steer packets through an 18 IPv6 or MPLS network using the source routing paradigm. This 19 document illustrates some use cases for Segment Routing in an IPv6 20 only environment. 22 Status of This Memo 24 This Internet-Draft is submitted in full conformance with the 25 provisions of BCP 78 and BCP 79. 27 Internet-Drafts are working documents of the Internet Engineering 28 Task Force (IETF). Note that other groups may also distribute 29 working documents as Internet-Drafts. The list of current Internet- 30 Drafts is at http://datatracker.ietf.org/drafts/current/. 32 Internet-Drafts are draft documents valid for a maximum of six months 33 and may be updated, replaced, or obsoleted by other documents at any 34 time. It is inappropriate to use Internet-Drafts as reference 35 material or to cite them other than as "work in progress." 37 This Internet-Draft will expire on December 15, 2017. 39 Copyright Notice 41 Copyright (c) 2017 IETF Trust and the persons identified as the 42 document authors. All rights reserved. 44 This document is subject to BCP 78 and the IETF Trust's Legal 45 Provisions Relating to IETF Documents 46 (http://trustee.ietf.org/license-info) in effect on the date of 47 publication of this document. Please review these documents 48 carefully, as they describe your rights and restrictions with respect 49 to this document. Code Components extracted from this document must 50 include Simplified BSD License text as described in Section 4.e of 51 the Trust Legal Provisions and are provided without warranty as 52 described in the Simplified BSD License. 54 Table of Contents 56 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 57 2. IPv6 SPRING use cases . . . . . . . . . . . . . . . . . . . . 2 58 2.1. SPRING in the Home Network . . . . . . . . . . . . . . . 2 59 2.2. SPRING in the Access Network . . . . . . . . . . . . . . 4 60 2.3. SPRING in Data Center . . . . . . . . . . . . . . . . . . 4 61 2.4. SPRING in Content Delivery Networks . . . . . . . . . . . 5 62 2.5. SPRING in Core networks . . . . . . . . . . . . . . . . . 5 63 3. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 6 64 4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 65 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 66 6. Security Considerations . . . . . . . . . . . . . . . . . . . 7 67 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 68 7.1. Informative References . . . . . . . . . . . . . . . . . 8 69 7.2. Normative References . . . . . . . . . . . . . . . . . . 8 70 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 72 1. Introduction 74 Source Packet Routing in Networking (SPRING) architecture leverages 75 the source routing paradigm. An ingress node steers a packet through 76 a controlled set of instructions, called segments, by prepending the 77 packet with SPRING header. The SPRING architecture is described in 78 [I-D.ietf-spring-segment-routing]. This document illustrates some 79 use cases for SPRING/Segment Routing in an IPv6 only environment. 81 2. IPv6 SPRING use cases 83 The use cases described in the section do not constitute an 84 exhaustive list of all the possible scenarios: this section only 85 includes some of the most common envisioned deployment models for 86 IPv6 Segment Routing. 88 In addition to the use cases described in this document, all the 89 SPRING use cases [RFC7855] are also applicable to the SRv6 data 90 plane. 92 2.1. SPRING in the Home Network 94 An IPv6-enabled home network provides ample globally routed IP 95 addresses for all devices in the home. An IPv6 home network with 96 multiple egress points and associated provider-assigned prefixes 97 will, in turn, provide multiple IPv6 addresses to hosts. A homenet 98 performing Source and Destination Routing 99 ([I-D.ietf-rtgwg-enterprise-pa-multihoming]) will ensure that packets 100 exit the home at the appropriate egress based on the associated 101 delegated prefix for that link. 103 A SPRING enabled home provides the ability to steer traffic into a 104 specific path from end-hosts in the home, or from a customer edge 105 router in the home. If the selection of the source routed path is 106 enabled at the customer edge router, that router is responsible for 107 classifying traffic and steering it into the correct path. If hosts 108 in the home have explicit source selection rules, classification can 109 be based on source address or associated network egress point, 110 avoiding the need for DPI-based implicit classification techniques. 111 If the traffic is steered into a specific path by the host itself, it 112 is important to know which networks can interpret the SPRING header. 113 This information can be provided as part of host configuration as a 114 property of the configured IP address. 116 The ability to steer traffic to an appropriate egress or utilize a 117 specific type of media (e.g., low-power, WIFI, wired, femto-cell, 118 bluetooth, MOCA, HomePlug, etc.) within the home itself are obvious 119 cases which may be of interest to an application running within a 120 home network. 122 Steering to a specific egress point may be useful for a number of 123 reasons, including: 125 o Regulatory 127 o Performance of a particular service associated with a particular 128 link 130 o Cost imposed due to data-caps or per-byte charges 132 o Home vs. work traffic in homes with one or more teleworkers, etc. 134 o Specific services provided by one ISP vs. another 136 Information included in the SPRING header, whether imposed by the 137 end-host itself, a customer edge router, or within the access network 138 of the ISP, may be of use at the far ends of the data communication 139 as well. For example, an application running on an end-host with 140 application-support in a data center can utilize the SPRING header as 141 a channel to include information that affects its treatment within 142 the data center itself, allowing for application-level steering and 143 load-balancing without relying upon implicit application 144 classification techniques at the data-center edge. Further, as more 145 and more application traffic is encrypted, the ability to extract 146 (and include in the SPRING header) just enough information to enable 147 the network and data center to load-balance and steer traffic 148 appropriately becomes more and more important. 150 2.2. SPRING in the Access Network 152 Access networks deliver a variety of types of traffic from the 153 service provider's network to the home environment and from the home 154 towards the service provider's network. 156 For bandwidth management or related purposes, the service provider 157 may want to associate certain types of traffic to specific physical 158 or logical downstream capacity pipes. 160 This mapping is not the same thing as classification and scheduling. 161 In the Cable access network, each of these pipes are represented at 162 the DOCSIS [DOCSIS] layer as different service flows, which are 163 better identified as differing data links. As such, creating this 164 separation allows an operator to differentiate between different 165 types of content and perform a variety of differing functions on 166 these pipes, such as byte capping, regulatory compliance functions, 167 and billing. 169 In a cable operator's environment, these downstream pipes could be a 170 specific QAM (Quadrature Amplitude Modulation) [QAM], a DOCSIS (Data 171 Over Cable Service Interface Specification) [DOCSIS] service flow or 172 a service group. 174 Similarly, the operator may want to map traffic from the home sent 175 towards the service provider's network to specific upstream capacity 176 pipes. Information carried in a packet's SPRING header could provide 177 the target pipe for this specific packet. The access device would 178 not need to know specific details about the packet to perform this 179 mapping; instead the access device would only need to know the 180 interpretation of the SPRING header and how to map it to the target 181 pipe. 183 2.3. SPRING in Data Center 185 Some Data Center operators are transitioning their Data Center 186 infrastructure from IPv4 to native IPv6 only, in order to cope with 187 IPv4 address depletion and to achieve larger scale. In such 188 environment, source routing, as enabled by Segment Routing IPv6, can 189 be used to steer traffic across specific paths through the network. 190 The specific path may also include a given function one or more nodes 191 in the path are requested to perform. 193 In addition one of the fundamental requirements for Data Center 194 architecture is to provide scalable, isolated tenant networks. In 195 such scenarios, Segment Routing can be used to identify specific 196 nodes, tenants, and functions and to build a construct to steer the 197 traffic across that specific path. 199 2.4. SPRING in Content Delivery Networks 201 The rise of online video applications and new, video-capable IP 202 devices has led to an explosion of video traffic traversing network 203 operator infrastructures. In the drive to reduce the capital and 204 operational impact of the massive influx of online video traffic, as 205 well as to extend traditional TV services to new devices and screens, 206 network operators are increasingly turning to Content Delivery 207 Networks (CDNs). 209 Several studies showed the benefits of connecting caches in a 210 hierarchical structure following the hierarchical nature of the 211 Internet. In a cache hierarchy one cache establishes peering 212 relationships with its neighbor caches. There are two types of 213 relationship: parent and sibling. A parent cache is essentially one 214 level up in a cache hierarchy. A sibling cache is on the same level. 215 Multiple levels of hierarchy are commonly used in order to build 216 efficient caches architecture. 218 In an environment, where each single cache system can be uniquely 219 identified by its own IPv6 address, a list containing a sequence of 220 the caches in a hierarchy can be built. At each node (cache) in the 221 list, the presence of the requested content is checked. If the 222 requested content is found at the cache (cache hits scenario) the 223 sequence ends, even if there are more nodes in the list; otherwise 224 next element in the list (next node/cache) is examined. 226 2.5. SPRING in Core networks 228 While the overall amount of traffic offered to the network continues 229 to grow and considering that multiple types of traffic with different 230 characteristics and requirements are quickly converging over single 231 network architecture, the network operators are starting to face new 232 challenges. 234 Some operators are currently building, or plan to build in the near 235 future, an IPv6 only native infrastructure for their core network. 236 These operators are also looking at the possibility to setup an 237 explicit path based on the IPv6 source address for specific types of 238 traffic in order to efficiently use their network infrastructure. In 239 case of IPv6 some operators are currently assigning or plan to assign 240 IPv6 prefix(es) to their IPv6 customers based on regions/geography, 241 thus the subscriber's IPv6 prefix could be used to identify the 242 region where the customer is located. In such environment the IPv6 243 source address could be used by the Edge nodes of the network to 244 steer traffic and forward it through a specific path other than the 245 optimal path. 247 The need to setup a source-based path, going through some specific 248 middle/intermediate points in the network may be related to different 249 requirements: 251 o The operator may want to be able to use some high bandwidth links 252 for specific type of traffic (like video) avoiding the need for 253 over-dimensioning all the links of the network; 255 o The operator may want to be able to setup a specific path for 256 delay sensitive applications; 258 o The operator may have the need to be able to select one (or 259 multiple) specific exit point(s) at peering points when different 260 peering points are available; 262 o The operator may have the need to be able to setup a source based 263 path for specific services in order to be able to reach some 264 servers hosted in some facilities not always reachable through the 265 optimal path; 267 o The operator may have the need to be able to provision guaranteed 268 disjoint paths (so-called dual-plane network) for diversity 269 purposes 271 All these scenarios would require a form of traffic engineering 272 capabilities in an IPv6 only network environment. 274 3. Contributors 276 Many people contributed to this document. The authors of this 277 document would like to thank and recognize them and their 278 contributions. These contributors provided invaluable concepts and 279 content for this document's creation. 281 Ida Leung 282 Rogers Communications 283 8200 Dixie Road 284 Brampton, ON L6T 0C1 285 CANADA 287 Email: Ida.Leung@rci.rogers.com 289 Stefano Previdi 290 Cisco Systems 291 Via Del Serafico, 200 292 Rome 00142 293 Italy 295 Email: sprevidi@cisco.com 297 Christian Martin 298 Cisco Systems 300 Email: martincj@cisco.com 302 4. Acknowledgements 304 The authors would like to thank Brian Field, Robert Raszuk, Wes 305 George, Eric Vyncke, Fred Baker, John G. Scudder, Adrian Farrel, 306 Alvaro Retana, Bruno Decraene and Yakov Rekhter for their valuable 307 comments and inputs to this document. 309 5. IANA Considerations 311 This document does not require any action from IANA. 313 6. Security Considerations 315 This document presents use cases to be considered by the SPRING 316 architecture and potential IPv6 extensions. As such, it does not 317 introduce any security considerations. However, there are a number 318 of security concerns with source routing at the IP layer [RFC5095]. 319 It is expected that any solution that addresses these use cases to 320 also address any security concerns. 322 7. References 324 7.1. Informative References 326 [DOCSIS] "DOCSIS Specifications Page", 327 . 330 [I-D.ietf-rtgwg-enterprise-pa-multihoming] 331 Baker, F., Bowers, C., and J. Linkova, "Enterprise 332 Multihoming using Provider-Assigned Addresses without 333 Network Prefix Translation: Requirements and Solution", 334 draft-ietf-rtgwg-enterprise-pa-multihoming-00 (work in 335 progress), March 2017. 337 [I-D.ietf-spring-segment-routing] 338 Filsfils, C., Previdi, S., Decraene, B., Litkowski, S., 339 and R. Shakir, "Segment Routing Architecture", draft-ietf- 340 spring-segment-routing-11 (work in progress), February 341 2017. 343 [QAM] "QAM specification", . 346 [RFC5095] Abley, J., Savola, P., and G. Neville-Neil, "Deprecation 347 of Type 0 Routing Headers in IPv6", RFC 5095, 348 DOI 10.17487/RFC5095, December 2007, 349 . 351 7.2. Normative References 353 [RFC7855] Previdi, S., Ed., Filsfils, C., Ed., Decraene, B., 354 Litkowski, S., Horneffer, M., and R. Shakir, "Source 355 Packet Routing in Networking (SPRING) Problem Statement 356 and Requirements", RFC 7855, DOI 10.17487/RFC7855, May 357 2016, . 359 Authors' Addresses 361 John Brzozowski 362 Comcast 364 Email: john_brzozowski@cable.comcast.com 365 John Leddy 366 Comcast 368 Email: John_Leddy@cable.comcast.com 370 Clarence Filsfils 371 Cisco Systems 372 Brussels 373 BE 375 Email: cfilsfil@cisco.com 377 Roberta Maglione (editor) 378 Cisco Systems 379 Via Torri Bianche 8 380 Vimercate 20871 381 Italy 383 Email: robmgl@cisco.com 385 Mark Townsley 386 Cisco Systems 388 Email: townsley@cisco.com