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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Networking Working Group R. Chen 3 Internet-Draft S. Peng 4 Intended status: Standards Track ZTE Corporation 5 Expires: October 20, 2021 April 18, 2021 7 IGP Extensions to Support Flex-Algorithm Aware Traffic Engineering 8 draft-cp-lsr-fa-aware-te-00 10 Abstract 12 [I-D.ietf-lsr-flex-algo]proposes a solution that allows IGPs 13 themselves to compute constraint based paths over the network, and it 14 also specifies a way of using Segment Routing (SR) Prefix-SIDs and 15 SRv6 locators to steer packets along the constraint-based paths. 17 [RFC8570] describes IS-IS extensions to distribute network- 18 performance information (such as residual bandwidth, and available 19 bandwidth). 21 This draft describes the IGP extensions to advertise the 22 corresponding network-performance information of the Flex-Algorithm. 24 Status of This Memo 26 This Internet-Draft is submitted in full conformance with the 27 provisions of BCP 78 and BCP 79. 29 Internet-Drafts are working documents of the Internet Engineering 30 Task Force (IETF). Note that other groups may also distribute 31 working documents as Internet-Drafts. The list of current Internet- 32 Drafts is at https://datatracker.ietf.org/drafts/current/. 34 Internet-Drafts are draft documents valid for a maximum of six months 35 and may be updated, replaced, or obsoleted by other documents at any 36 time. It is inappropriate to use Internet-Drafts as reference 37 material or to cite them other than as "work in progress." 39 This Internet-Draft will expire on October 20, 2021. 41 Copyright Notice 43 Copyright (c) 2021 IETF Trust and the persons identified as the 44 document authors. All rights reserved. 46 This document is subject to BCP 78 and the IETF Trust's Legal 47 Provisions Relating to IETF Documents 48 (https://trustee.ietf.org/license-info) in effect on the date of 49 publication of this document. Please review these documents 50 carefully, as they describe your rights and restrictions with respect 51 to this document. Code Components extracted from this document must 52 include Simplified BSD License text as described in Section 4.e of 53 the Trust Legal Provisions and are provided without warranty as 54 described in the Simplified BSD License. 56 Table of Contents 58 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 59 2. Conventions used in this document . . . . . . . . . . . . . . 3 60 3. IS-IS Extensins for FA-TE . . . . . . . . . . . . . . . . . . 3 61 3.1. Maximum Reservable Link Bandwidth per Algorithm Sub-TLV . 3 62 3.2. Available Link Bandwidth per Algorithm Sub-TLV . . . . . 4 63 3.3. Utilized Link Bandwidth per Algorithm Sub-TLV . . . . . . 5 64 4. OSPF Extensins for FA-TE . . . . . . . . . . . . . . . . . . 6 65 5. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 6 66 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 67 7. Security Considerations . . . . . . . . . . . . . . . . . . . 8 68 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 69 9. Normative References . . . . . . . . . . . . . . . . . . . . 8 70 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 72 1. Introduction 74 [I-D.ietf-lsr-flex-algo]proposes a solution that allows IGPs 75 themselves to compute constraint based paths over the network, and it 76 also specifies a way of using Segment Routing (SR) Prefix-SIDs and 77 SRv6 locators to steer packets along the constraint-based paths. 79 [RFC8570] describes IS-IS extensions to distribute network- 80 performance information (such as link delay, delay variation, packet 81 loss, residual bandwidth, and available bandwidth). 83 The current Flex-Algorithm technology may support the implementation 84 of different QoS (Quality of Service QoS) policies of different 85 algorithms (algorithm) at the forwarding plane. It includes 86 different bandwidth, traffic class of service, queue scheduling 87 policies (such as low-delay queue, Priority Queuing priority queue) 88 and discard policies (such as tail discard and random discard). This 89 is actually the local behavior of the forwarding plane inside a node. 90 However, it's not enough. In order to comprehensively optimize the 91 service traffic running in each Flex-Algorithm and avoid unnecessary 92 traffic congestion, the relevant path control technology needs to be 93 implemented in the control plane. That is, to manage and maintain 94 the bandwidth resource reservation and consumption information for 95 each Flex-algo plane, and use the information for path calculation 96 and orchestration of the Flex-Algorithm. 98 This draft describes the IGP extensions to advertise the 99 corresponding network-performance information of the Flex-Algorithm. 101 2. Conventions used in this document 103 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 104 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 105 document are to be interpreted as described in RFC2119. 107 3. IS-IS Extensins for FA-TE 109 This document registers new IS-IS FA-TE sub-TLVs in the "Sub-TLVs for 110 TLVs 22, 23, 141, 222, and 223" registry. These new sub-TLVs provide 111 ways to distribute network-performance information of the Flex- 112 Algorithm. 114 This document registers several sub-TLVs: 116 Type Description 117 ---------------------------------------------------- 119 TBD Maximum Reservable Link Bandwidth per Algorithm 121 TBD Available Bandwidth per Algorithm 123 TBD Utilized Bandwidth per Algorithm 125 3.1. Maximum Reservable Link Bandwidth per Algorithm Sub-TLV 127 This sub-TLV advertises maximum reservable link bandwidth attributes 128 on a particular link for a Flex-Algorithm. 130 The Maximum Reservable Link Bandwidth per Algorithm Sub-TLV has the 131 following format: 133 0 1 2 3 134 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 135 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 136 | Type | Length | Algorithm | 137 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 138 | Maximum Reservable Link Bandwidth | 139 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 141 Figure 1 143 Type: TBD1 (Suggested value to be assigned by IANA) 145 Length: 1 octets. 147 Algorithm: 1 octets. Flex-Algorithm number,the value between 128 and 148 255 inclusive,the same as the definition of Flex-Algorithm in 149 [I-D.ietf-lsr-flex-algo]. Indicates that the value in the Maximum 150 Reserved Link Bandwidth field is for a specific Flex-algo plane. 152 Maximum Reserved Link Bandwidth: 4 octets.Indicates the maximum link 153 bandwidth that can be reserved for a specific FA-algorithm. 155 Note that the maximum reserved link bandwidth irrelevant to Flex-algo 156 can be classified as MRLB-FA corresponding to algorithm 0. 157 Therefore, the Sub-TLV (set the Algorithm field to 0) or the Maximum 158 Reservable Link Bandwidth Sub-TLV defined by [RFC5305] can be used.If 159 a node receives two types of notifications at the same time, the 160 bandwidth value carried in the conventional known Sub-TLV is 161 preferred. 163 3.2. Available Link Bandwidth per Algorithm Sub-TLV 165 This Sub-TLV advertises the available bandwidth on a particular link 166 for a specific Flex-Algorithm. 168 The Available Link Bandwidth per Algorithm Sub-TLV has the following 169 format: 171 0 1 2 3 172 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 173 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 174 | Type | Length | Algorithm | 175 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 176 | Available Link Bandwidth | 177 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 179 Figure 3 181 Type: TBD3 (Suggested value to be assigned by IANA) 183 Length: 1 octets. 185 Algorithm: 1 octets. Flex-Algorithm number,the value between 128 and 186 255 inclusive,the same as the definition of Flex-Algorithm in 187 [I-D.ietf-lsr-flex-algo]. Indicates that the value in the Available 188 Link Bandwidth field is for a specific Flex-algo plane. 190 Available Link Bandwidth: 4 octets. Indicates the available link 191 bandwidth that can be reserved for a specific FA-algorithm. 193 Note that the available link bandwidth irrelevant to Flex-algo can be 194 classified as ARLB-FA corresponding to algorithm 0. Therefore, the 195 Sub-TLV (set the Algorithm field to 0) or the Unidirectional 196 Available Bandwidth Sub-TLV defined by [RFC8570] can be used.If a 197 node receives two types of notifications at the same time, the 198 bandwidth value carried in the conventional known Sub-TLV is 199 preferred. 201 3.3. Utilized Link Bandwidth per Algorithm Sub-TLV 203 This Sub-TLV advertises the utilized bandwidth on a particular link 204 for a specific Flex-Algorithm. 206 The Utilized Link Bandwidth per Algorithm Sub-TLV has the following 207 format: 209 0 1 2 3 210 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 211 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 212 | Type | Length | Algorithm | 213 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 214 | Utilized Link Bandwidth | 215 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 217 Figure 4 219 Type: TBD4 (Suggested value to be assigned by IANA) 221 Length: 1 octets. 223 Algorithm: 1 octets. Flex-Algorithm number,the value between 128 and 224 255 inclusive,the same as the definition of Flex-Algorithm in 225 [I-D.ietf-lsr-flex-algo]. Indicates that the value in the Utilized 226 Link Bandwidth field is for a specific Flex-Algorithm plane. 228 Utilized Link Bandwidth: 4 octets. Indicates the Utilized link 229 bandwidth that can be reserved for a specific Flex-Algorithm. 231 Note that the Utilized link bandwidth irrelevant to Flex-algo can be 232 classified as ULB-FA corresponding to algorithm 0. Therefore, the 233 Sub-TLV (set the Algorithm field to 0) or the Unidirectional Utilized 234 Bandwidth Sub-TLV defined by [RFC8570] can be used.If a node receives 235 two types of notifications at the same time, the bandwidth value 236 carried in the conventional known Sub-TLV is preferred. 238 4. OSPF Extensins for FA-TE 240 OSPF extensions for FA-TE will be defined in next version. 242 5. Examples 244 Assume two Flex-Algorithm, FA128 and FA129, with the following 245 configuration parameters: 247 Per TE link resource allocation: 248 Max-BW(interface): 100G (derived from the physical interface BW) 249 Max-resv-BW(interface): 100G (default: equal to Max-BW) 251 Flex-Algorithm: 252 Max-resv-link-BW(FA128): 10G 253 Max-resv-link-BW(FA129): 20G 254 Time0: no LSPs 255 When the controller is used for path calculation, the controller first collects the network 256 topology information through the BGP-LS, which contains the MRLB-FA/ULB-FA/ALB-FA information 257 of each link. Static bandwidth reservation information maintained by the controller: 258 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 259 | TE link | Flex-Algorithm | Bandwidth | 260 |-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| 261 | | FA0 | MRLB-FA = 70G | ULB-A = 0 | ALB-A = 70G | 262 | |-+-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| 263 | Link 1 | FA128 | MRLB-FA = 10G | ULB-A = 0 | ALB-A = 10G | 264 | |-+-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| 265 | | FA129 | MRLB-FA = 20G | ULB-A = 0 | ALB-A = 20G | 266 +-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| 268 Time1: Create a new TE path1 in FA 128 with reserved bandwidth of 5G 269 The controller updates the reserved static bandwidth information: 270 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 271 | TE link | Flex-Algorithm | Bandwidth | 272 |-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| 273 | | FA0 | MRLB-FA = 70G | ULB-FA = 0| ALB-FA = 70G | 274 | |-+-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| 275 | Link 1 | FA128 | MRLB-FA = 10G | ULB-FA = 0| ALB-FA = 10G | 276 | | | (TE path1 statically | | | 277 | | |reserve 5G, remaining 5G}| | | 278 | |-+-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-+-+-+-+-|-+-+-+-+-+-|-+-+-+-+-+-+-+-+-| 279 | | FA129 | MRLB-FA = 20G | ULB-FA = 0| ALB-FA = 20G | 280 +-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 282 Time3: After the TE path1 starts to carry traffic, suppose the service traffic on the TE path1 283 runs at full load.The controller updates the reserved static bandwidth information: 284 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 285 | TE link | Flex-Algorithm | Bandwidth | 286 |-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| 287 | | FA0 | MRLB-FA = 70G | ULB-FA = 0 | ALB-FA = 70G | 288 | |-+-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| 289 | Link 1 | FA128 | MRLB-FA = 10G | ULB-FA = 5G | ALB-FA = 5G | 290 | | | (TE path1 statically | | | 291 | | |reserve 5G, remaining 5G}| | | 292 | |-+-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-+-+-+-+-|-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-| 293 | | FA129 | MRLB-FA = 20G | ULB-FA = 0 | ALB-FA = 20G | 294 +-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-|-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 296 Now suppose to continue to create another TE path2 in the Flex-algo 128. 297 This TE path needs to reserve 6G bandwidth. When the controller is used for path computation, 298 path computation will fail, Beacuse there is no link resource that meets the bandwidth requirement. 300 6. IANA Considerations 302 IANA maintains the registry for the sub-TLVs. IANA has registered 303 the following sub-TLVs in the "Sub-TLVs for TLVs 22, 23, 141, 222, 304 and 223" registry: 306 Type Description 307 ---------------------------------------------------- 309 TBD Maximum Reservable Link Bandwidth per Algorithm 311 TBD Residual Bandwidth per Algorithm 313 TBD Available Bandwidth per Algorithm 315 TBD Utilized Bandwidth per Algorithm 317 7. Security Considerations 319 TBD. 321 8. Acknowledgements 323 TBD. 325 9. Normative References 327 [I-D.ietf-lsr-flex-algo] 328 Psenak, P., Hegde, S., Filsfils, C., Talaulikar, K., and 329 A. Gulko, "IGP Flexible Algorithm", draft-ietf-lsr-flex- 330 algo-13 (work in progress), October 2020. 332 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 333 Requirement Levels", BCP 14, RFC 2119, 334 DOI 10.17487/RFC2119, March 1997, 335 . 337 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic 338 Engineering", RFC 5305, DOI 10.17487/RFC5305, October 339 2008, . 341 [RFC8570] Ginsberg, L., Ed., Previdi, S., Ed., Giacalone, S., Ward, 342 D., Drake, J., and Q. Wu, "IS-IS Traffic Engineering (TE) 343 Metric Extensions", RFC 8570, DOI 10.17487/RFC8570, March 344 2019, . 346 Authors' Addresses 348 Ran Chen 349 ZTE Corporation 351 Email: chen.ran@zte.com.cn 353 Shaofu Peng 354 ZTE Corporation 356 Email: peng.shaofu@zte.com.cn