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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 TEAS Working Group A.Wang 2 Internet Draft China Telecom 3 Quintin Zhao 4 Boris Khasanov 5 HuaiMo Chen 6 Huawei Technologies 7 Penghui Mi 8 Tencent Company 9 Raghavendra Mallya 10 Juniper Networks 11 Shaofu Peng 12 ZTE Corporation 14 Intended status: Standard Track October 24, 2017 15 Expires: April 23, 2018 17 PCE in Native IP Network 18 draft-wang-teas-pce-native-ip-04.txt 20 Status of this Memo 22 This Internet-Draft is submitted in full conformance with the 23 provisions of BCP 78 and BCP 79. 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. This document may not be modified, 27 and derivative works of it may not be created, and it may not be 28 published except as an Internet-Draft. 30 This Internet-Draft is submitted in full conformance with the 31 provisions of BCP 78 and BCP 79. This document may not be modified, 32 and derivative works of it may not be created, except to publish it 33 as an RFC and to translate it into languages other than English. 35 it for publication as an RFC or to translate it into languages other 36 than English. 38 Internet-Drafts are working documents of the Internet Engineering 39 Task Force (IETF), its areas, and its working groups. Note that 40 other groups may also distribute working documents as Internet- 41 Drafts. 43 Internet-Drafts are draft documents valid for a maximum of six 44 months and may be updated, replaced, or obsoleted by other documents 45 at any time. It is inappropriate to use Internet-Drafts as 46 reference material or to cite them other than as "work in progress." 48 The list of current Internet-Drafts can be accessed at 49 http://www.ietf.org/ietf/1id-abstracts.txt 50 The list of Internet-Draft Shadow Directories can be accessed at 51 http://www.ietf.org/shadow.html 53 This Internet-Draft will expire on April 23, 2018. 55 Copyright Notice 57 Copyright (c) 2017 IETF Trust and the persons identified as the 58 document authors. All rights reserved. 60 This document is subject to BCP 78 and the IETF Trust's Legal 61 Provisions Relating to IETF Documents 62 (http://trustee.ietf.org/license-info) in effect on the date of 63 publication of this document. Please review these documents 64 carefully, as they describe your rights and restrictions with 65 respect to this document. 67 Abstract 69 This document defines the solution for CCDR traffic engineering within 70 Native IP network, using Dual/Multi-BGP session strategy and PCE-based 71 central control architecture. 73 The proposed central mode control solution conforms to the concept that 74 defined in draft [I-D.draft-ietf-teas-pce-control-function]. 76 The scenario and simulation results of CCDR traffic engineering is 77 described in draft [I-D.draft-wang-teas-ccdr] 79 Table of Contents 81 1. Introduction ................................................ 3 82 2. Conventions used in this document............................ 3 83 3. Dual-BGP solution for simple topology........................ 3 84 4. Dual-BGP in large Scale Topology............................. 5 85 5. Multi-BGP for Extended Traffic Differentiation .............. 5 86 6. CCDR based solution for Multi-BGP strategy deployment........ 6 87 7. PCEP extension for key parameters delivery. ................. 7 88 8. CCDR Deployment Consideration................................ 8 89 9. Security Considerations...................................... 9 90 10. IANA Considerations......................................... 9 91 11. Conclusions ................................................ 9 92 12. References ................................................. 9 93 12.1. Normative References................................... 9 94 12.2. Informative References................................. 9 95 13. Acknowledgments ........................................... 10 97 1. Introduction 99 Draft [I-D.draft-wang-teas-ccdr] describes the scenario and 100 simulation results for the CCDR traffic engineering. In summary, the 101 requirements for CCDR traffic engineering in Native IP network are 102 the following: 103 1) No complex MPLS signaling procedure. 104 2) End to End traffic assurance, determined QoS behavior. 105 3) Flexible deployment and automation control. 107 This document defines the solution for CCDR traffic engineering 108 within Native IP network, using Dual/Multi-BGP session strategy and 109 CCDR architecture, to meet the above requirements in dynamical and 110 central control mode. Future PCEP protocol extensions to transfer the 111 key parameters between PCE and the underlying network devices(PCC) 112 are provided in draft [draft-wang-pcep-extension-native-IP] 114 2. Conventions used in this document 116 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 117 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 118 document are to be interpreted as described in RFC 2119 [RFC2119]. 120 3. Dual-BGP solution for simple topology. 122 Dual-BGP solution for simple topology is illustrated in Fig.1, which 123 is comprised by SW1, SW2, R1, R2. There are multiple physical links 124 between R1 and R2. Traffic between IP11 and IP21 is normal traffic, 125 traffic between IP12 and IP22 is priority traffic that should be 126 treated differently. 128 Only Native IGP/BGP protocol is deployed between R1 and R2. The 129 traffic between each address pair may change timely and the 130 corresponding source/destination addresses of the traffic may also 131 change dynamically. 133 The key idea of the Dual-BGP solution for this simple topology is the 134 following: 135 1) Build two BGP sessions between R1 and R2, via the different 136 loopback address lo0, lo1 on these routers. 137 2) Send different prefixes via the two BGP sessions. (For example, 138 IP11/IP21 via the BGP pair 1 and IP12/IP22 via the BGP pair 2). 140 3) Set the explicit peer route on R1 and R2 respectively for BGP 141 next hop of lo0, lo1 to different physical link address between 142 R1 and R2. 144 So, the traffic between the IP11 and IP21, and the traffic between 145 IP12 and IP22 will go through different physical links between R1 and 146 R2, each type of traffic occupy the different dedicated physical 147 links. 149 If there is more traffic between IP12 and IP22 that needs to be 150 assured , one can add more physical links on R1 and R2 to reach the 151 loopback address lo1(also the next hop for BGP Peer pair2). In this 152 cases the prefixes that advertised by two BGP peer need not be 153 changed. 155 If, for example, there is traffic from another address pair that 156 needs to be assured (for example IP13/IP23), but the total volume of 157 assured traffic does not exceed the capacity of the previous 158 appointed physical links, then one need only to advertise the newly 159 added source/destination prefixes via the BGP peer pair2, then the 160 traffic between IP13/IP23 will go through the assigned dedicated 161 physical links as the traffic between IP12/IP22. 163 Such decouple philosophy gives the network operator more flexible 164 control ability on the network traffic, get the determined QoS 165 assurance effect to meet the application's requirement. No complex 166 MPLS signal procedures is introduced, the router need only support 167 native IP protocol. 169 | BGP Peer Pair2 | 170 +------------------+ 171 |lo1 lo1 | 172 | | 173 | BGP Peer Pair1 | 174 +------------------+ 175 IP12 |lo0 lo0 | IP22 176 IP11 | | IP21 177 SW1-------R1-----------------R2-------SW2 178 Links Group 180 Fig.1 Design Philosophy for Dual-BGP Solution 182 4. Dual-BGP in large Scale Topology 184 When the assured traffic spans across one large scale network, as 185 that illustrated in Fig.2, the dual BGP sessions cannot be 186 established hop by hop especially for the iBGP within one AS. For 187 such scenario, we should consider to use the Route Reflector (RR) to 188 achieve the similar Dual-BGP effect, select one router which performs 189 the role of RR (for example R3 in Fig.2), every other edge router 190 will establish two BGP peer sessions with the RR, using their 191 different loopback addresses respectively. The other two steps for 192 traffic differentiation are same as one described in the Dual-BGP 193 simple topology usage case. 195 For the example shown in Fig.2, if we select the R1-R2-R4-R7 as the 196 dedicated path, then we should set the explicit peer routes on these 197 routers respectively, pointing to the BGP next hop (loopback 198 addresses of R1 and R7, which are used to send the prefix of the 199 assured traffic) to the actual address of the physical link 201 +------------R3--------------+ 202 | | 203 SW1-------R1-------R5---------R6-------R7--------SW2 204 | | | | 205 +-------R2---------R4--------+ 207 Fig.2 Dual-BGP solution for large scale network 209 5. Multi-BGP for Extended Traffic Differentiation 211 In general situation, several additional traffic differentiation 212 criteria exist, including: 213 1) Traffic that requires low latency links and is not sensitive to 214 packet loss 215 2) Traffic that requires low packet loss but can endure higher latency 216 3) Traffic that requires lowest jitter path 217 4) Traffic that requires high bandwidth links 219 These different traffic requirements can be summarized in the 220 following table: 222 +----------+-------------+---------------+-----------------+ 223 | Flow No. | Latency | Packet Loss | Jitter | 224 +----------+-------------+---------------+-----------------+ 225 | 1 | Low | Normal | Don't care | 226 +----------+-------------+---------------+-----------------+ 227 | 2 | Normal | Low | Dont't care | 228 +----------+-------------+---------------+-----------------+ 229 | 3 | Normal | Normal | Low | 230 +----------+-------------+---------------+-----------------+ 231 Table 1. Traffic Requirement Criteria 233 For Flow No.1, we can select the shortest distance path to carry the 234 traffic; for Flow No.2, we can select the idle links to form its end 235 to end path; for Flow No.3, we can let all the traffic pass one 236 single path, no ECMP distribution on the parallel links is required. 238 It is difficult and almost impossible to provide an end-to-end (E2E) 239 path with latency, latency variation, packet loss, and bandwidth 240 utilization constraints to meet the above requirements in large scale 241 IP-based network via the traditional distributed routing protocol, 242 but these requirements can be solved using the CCDR architecture 243 since the PCE has the overall network view, can collect real network 244 topology and network performance information about the underlying 245 network, select the appropriate path to meet the various network 246 performance requirements of different traffic type. 248 6. CCDR based solution for Multi-BGP strategy deployment. 250 With the advent of SDN concepts towards pure IP networks, it is 251 possible now to accomplish the central and dynamic control of network 252 traffic according to the application's various requirements. 254 The procedure to implement the dynamic deployment of Multi-BGP 255 strategy is the following: 256 1) PCE gets topology and link utilization information from the 257 underlying network, calculate the appropriate link path upon 258 application's requirements. 259 2) PCE sends the key parameters to edge/RR routers(R1, R7 and R3 in 260 Fig.3) to build multi-BGP peer relations and advertise different 261 prefixes via them. 262 3) PCE sends the route information to the routers (R1,R2,R4,R7 in 263 Fig.3) on forwarding path via PCEP, to build the path to the BGP 264 next-hop of the advertised prefixes. 265 4) If the assured traffic prefixes were changed but the total volume 266 of assured traffic does not exceed the physical capacity of the 267 previous end-to-end path, then PCE needs only change the related 268 information on edge routers (R1,R7 in Fig.3). 269 5) If volume of the assured traffic exceeds the capacity of previous 270 calculated path, PCE must recalculate the appropriate path to 271 accommodate the exceeding traffic via some new end-to-end physical 272 link. After that PCE needs to update on-path routers to build such 273 path hop by hop. 275 +----+ 276 ***********+PCE +************* 277 * +--*-+ * 278 * / * \ * 279 * * * 280 PCEP* *BGP-LS/SNMP *PCEP 281 * * * 282 * * \ * / 283 \ * / * \ */ 284 \*/-----------R3--------------* 285 | | 286 | | 287 SW1-------R1-------R5---------R6-------R7--------SW2 288 | | | | 289 | | | | 290 +-------R2---------R4--------+ 292 Fig.3 PCE based solution for Multi-BGP deployment 294 7. PCEP extension for key parameters delivery. 296 The PCEP protocol needs to be extended to transfer the following key 297 parameters: 298 1) BGP peer address and advertised prefixes. 299 2) Explicit route information to BGP next hop of advertised prefixes. 301 Once the router receives such information, it should establish the 302 BGP session with the peer appointed in the PCEP message, advertise 303 the prefixes that contained in the corresponding PCEP message, and 304 build the end to end dedicated path hop by hop. Details of 305 communications between PCEP and BGP subsystems in router's control 306 plane are out of scope of this draft and will be described in 307 separate draft.[draft-wang-pce-extension for native IP] 309 The reason why we selected PCEP as the southbound protocol instead of 310 OpenFlow, is that PCEP is suitable for the changes in control plane 311 of the network devices, there OpenFlow dramatically changes the 312 forwarding plane. We also think that the level of centralization that 313 requires by OpenFlow is hardly achievable in many today's SP networks 314 so hybrid BGP+PCEP approach looks much more interesting. 316 8. CCDR Deployment Consideration 318 CCDR solution requires the parallel work of 2 subsystems in router's 319 control plane: PCE (PCEP) and BGP as well as coordination between 320 them, so it might require additional planning work before deployment. 322 8.1 Scalability 324 In CCDR solution, PCE needs only to influence the edge routers for 325 the prefixes differentiation via the multi-BGP deployment. The route 326 information for these prefixes within the on-path routers were 327 distributed via the traditional BGP protocol. Unlike the solution 328 from BGP Flowspec, the on-path router need only keep the specific 329 policy routes to the BGP next-hop of the differentiate prefixes, not 330 the specific routes to the prefixes themselves. This can lessen the 331 burden from the table size of policy based routes for the on-path 332 routers, and has more scalability when comparing with the solution 333 from BGP flowspec or Openflow. 335 8.2 High Availability 337 CCDR solution is based on the traditional distributed IP protocol. If 338 the PCE failed, the forwarding plane will not be impacted, as the BGP 339 session between all devices will not flap, and the forwarding table 340 will remain the same. If one node on the optimal path is failed, the 341 assurance traffic will fall over to the best-effort forwarding path. 342 One can even design several assurance paths to load balance/hot 343 standby the assurance traffic to meet the path failure situation, as 344 done in MPLS FRR. 345 From PCE/SDN-controller HA side we will rely on existing HA solutions 346 of SDN controllers such as clustering. 348 8.3 Incremental deployment 349 Not every router within the network support will support the PCEP 350 extension that defined in [draft-wang-pce-extension-native-IP] 351 simultaneously. For such situations, router on the edge of sub domain 352 can be upgraded first, and then the traffic can be assured between 353 different sub domains. Within each sub domain, the traffic will be 354 forwarded along the best-effort path. Service provider can 355 selectively upgrade the routers on each sub-domain in sequence. 357 9. Security Considerations 359 TBD 361 10. IANA Considerations 363 TBD 365 11. Conclusions 367 TBD 369 12. References 371 12.1. Normative References 373 [RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path 375 Computation Element (PCE)-Based Architecture", RFC 377 4655, August 2006,. 379 [RFC5440]Vasseur, JP., Ed., and JL. Le Roux, Ed., "Path 381 Computation Element (PCE) Communication Protocol 383 (PCEP)", RFC 5440, March 2009, 385 . 387 12.2. Informative References 389 [I-D.draft-ietf-teas-pce-control-function] 391 A.Farrel, Q.Zhao et al. "An Architecture for use of PCE and PCEP in 392 a Network with Central Control" 394 https://datatracker.ietf.org/doc/draft-ietf-teas-pce-central- 395 control/ September, 2016 397 [I-D.draft-wang-teas-ccdr] 399 A.Wang, X.Huang et al. "CCDR Scenario, Simulation and Suggestion" 401 https://datatracker.ietf.org/doc/draft-wang-teas-ccdr/ 403 [I-D. draft-ietf-teas-pcecc-use-cases] 405 Quintin Zhao, Robin Li, Boris Khasanov et al. "The Use Cases for 406 Using PCE as the Central Controller(PCECC) of LSPs 408 https://tools.ietf.org/html/draft-ietf-teas-pcecc-use-cases-00 410 March,2017 412 [draft-wang-pcep-extension for native IP] 414 Aijun Wang, Boris Khasanov et al. "PCEP Extension for Native IP 415 Network" https://datatracker.ietf.org/doc/draft-wang-pce-extension- 416 native-ip/ 418 13. Acknowledgments 420 The authors would like to thank George Swallow, Xia Chen, Jeff 421 Tantsura, Daniele Ceccarelli and Dhruv Dhody for their valuable 422 comments and suggestions. 424 The authors would also like to thank Lou Berger, Adrian Farrel, King 425 Daniel for their suggestions to put forward this draft. 427 Authors' Addresses 429 Aijun Wang 430 China Telecom 431 Beiqijia Town, Changping District 432 Beijing,China 434 Email: wangaj.bri@chinatelecom.cn 435 Quintin Zhao 436 Huawei Technologies 437 125 Nagog Technology Park 438 Acton, MA 01719 439 USA 441 EMail: quintin.zhao@huawei.com 443 Boris Khasanov 444 Huawei Technologies 445 Moskovskiy Prospekt 97A 446 St.Petersburg 196084 447 Russia 449 EMail: khasanov.boris@huawei.com 451 Huaimo Chen 452 Huawei Technologies 453 Boston, MA, 454 USA 456 EMail: Huaimo.chen@huawei.com 458 Penghui Mi 459 Tencent 460 Tencent Building, Kejizhongyi Avenue, 461 Hi-techPark, Nanshan District,Shenzhen 518057, P.R.China 463 Email kevinmi@tencent.com 465 Raghavendra Mallya 466 Juniper Networks 467 1133 Innovation Way 468 Sunnyvale, California 94089 USA 470 Email: rmallya@juniper.net 472 Shaofu Peng 473 ZTE Corporation 474 No.68 Zijinghua Road,Yuhuatai District 475 Nanjing 210012 476 China 478 Email: peng.shaofu@zte.com.cn