idnits 2.17.1 draft-ietf-teas-pce-native-ip-03.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 abstract seems to contain references ([RFC8283], [I-D.ietf-teas-native-ip-scenarios]), which it shouldn't. Please replace those with straight textual mentions of the documents in question. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == The document doesn't use any RFC 2119 keywords, yet seems to have RFC 2119 boilerplate text. -- The document date (April 16, 2019) is 1829 days in the past. Is this intentional? -- Found something which looks like a code comment -- if you have code sections in the document, please surround them with '' and '' lines. Checking references for intended status: Experimental ---------------------------------------------------------------------------- == Unused Reference: 'I-D.ietf-teas-pcecc-use-cases' is defined on line 416, but no explicit reference was found in the text == Unused Reference: 'RFC8253' is defined on line 433, but no explicit reference was found in the text == Outdated reference: A later version (-30) exists of draft-ietf-pce-pcep-extension-native-ip-03 == Outdated reference: A later version (-12) exists of draft-ietf-teas-native-ip-scenarios-02 == Outdated reference: A later version (-13) exists of draft-ietf-teas-pcecc-use-cases-03 Summary: 1 error (**), 0 flaws (~~), 7 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 TEAS Working Group A. Wang 3 Internet-Draft China Telecom 4 Intended status: Experimental Q. Zhao 5 Expires: October 18, 2019 B. Khasanov 6 H. Chen 7 Huawei Technologies 8 R. Mallya 9 Juniper Networks 10 April 16, 2019 12 PCE in Native IP Network 13 draft-ietf-teas-pce-native-ip-03 15 Abstract 17 This document defines the framework for traffic engineering within 18 native IP network, using Dual/Multi-BGP sessions strategy and PCE- 19 based central control architecture. The proposed central mode 20 control framework conforms to the concept that defined in [RFC8283]. 21 The scenario and simulation results of traffic engineering in Native 22 IP network is described in draft [I-D.ietf-teas-native-ip-scenarios]. 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 18, 2019. 41 Copyright Notice 43 Copyright (c) 2019 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. CCDR Framework in Simple Topology . . . . . . . . . . . . . . 3 61 4. CCDR Framework in Large Scale Topology . . . . . . . . . . . 4 62 5. CCDR Multi-BGP Strategy . . . . . . . . . . . . . . . . . . . 5 63 6. CCDR Framework for Multi-BGP Strategy . . . . . . . . . . . . 6 64 7. PCEP Extension for Key Parameters Delivery . . . . . . . . . 7 65 8. Deployment Consideration . . . . . . . . . . . . . . . . . . 8 66 8.1. Scalability . . . . . . . . . . . . . . . . . . . . . . . 8 67 8.2. High Availability . . . . . . . . . . . . . . . . . . . . 8 68 8.3. Incremental deployment . . . . . . . . . . . . . . . . . 8 69 9. Security Considerations . . . . . . . . . . . . . . . . . . . 9 70 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 71 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 9 72 12. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 9 73 13. Normative References . . . . . . . . . . . . . . . . . . . . 9 74 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 76 1. Introduction 78 Draft [I-D.ietf-teas-native-ip-scenarios] describes the scenarios, 79 simulation results and suggestions for traffic engineering in native 80 IP network. To meet the requirements of various scenarios, the 81 solution for traffic engineering in native IP network should have the 82 followings criteria: 84 o No complex MPLS signaling procedures. 86 o End to End traffic assurance, determined QoS behavior. 88 o Identical deployment method for intra-domain and inter-domain. 90 o No influence to forwarding behavior of the router. 92 o Can exploit the power of centrally control (PCE) and flexibility/ 93 robustness of distributed control protocol. 95 o Coping with the differentiation requirements for large amount 96 traffic and prefixes. 98 o Flexible deployment and automation control. 100 This document defines the framework for traffic engineering within 101 native IP network, using Dual/Multi-BGP session strategy, to meet the 102 above requirements in dynamical and centrally control mode(Centrally 103 Control Dynamic Routing, abbreviated as CCDR ). The related PCEP 104 protocol extensions to transfer the key parameters between PCE and 105 the underlying network devices(PCC) are provided in draft 106 [I-D.ietf-pce-pcep-extension-native-ip]. 108 2. Conventions used in this document 110 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 111 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 112 document are to be interpreted as described in RFC 2119 [RFC2119] . 114 3. CCDR Framework in Simple Topology 116 Fig.1 illustrates the CCDR framework for traffic engineering in 117 simple topology. The topology is comprised by four devices which are 118 SW1, SW2, R1, R2. There are multiple physical links between R1 and 119 R2. Traffic between IP11(on SW1) and IP21(on SW2) is normal traffic, 120 traffic between IP12(on SW1) and IP22(on SW2) is priority traffic 121 that should be treated differently. 123 Only native IGP/BGP protocol is deployed between R1 and R2. The 124 traffic between each address pair may change in real time and the 125 corresponding source/destination addresses of the traffic may also 126 change dynamically. 128 The key ideas of the CCDR framework for this simple topology are the 129 followings: 131 o Build two BGP sessions between R1 and R2, via the different 132 loopback address lo0, lo1 on these routers. 134 o Send different prefixes via the established BGP sessions. For 135 example, IP11/IP21 via the BGP pair 1 and IP12/IP22 via the BGP 136 pair 2. 138 o Set the explicit peer route on R1 and R2 respectively for BGP next 139 hop of lo0, lo1 to different physical link address between R1 and 140 R2. 142 After the above actions, the traffic between the IP11 and IP21, and 143 the traffic between IP12 and IP22 will go through different physical 144 links between R1 and R2, each set of traffic occupies different 145 dedicated physical links. 147 If there is more traffic between IP12 and IP22 that needs to be 148 assured , one can add more physical links between R1 and R2 to reach 149 the loopback address lo1(also the next hop for BGP Peer pair2). In 150 this cases the prefixes that advertised by the BGP peers need not be 151 changed. 153 If, for example, there is traffic from another address pair that 154 needs to be assured (for example IP13/IP23), and the total volume of 155 assured traffic does not exceed the capacity of the previous 156 appointed physical links, one need only to advertise the newly added 157 source/destination prefixes via the BGP peer pair2. The traffic 158 between IP13/IP23 will go through the assigned dedicated physical 159 links as the traffic between IP12/IP22. 161 Such decouple philosophy gives network operator flexible control 162 ability on the network traffic, achieve the determined QoS assurance 163 effect to meet the application's requirement. No complex MPLS signal 164 procedures is introduced, the router needs only support native IP 165 protocol. 167 | BGP Peer Pair2 | 168 +------------------+ 169 |lo1 lo1 | 170 | | 171 | BGP Peer Pair1 | 172 +------------------+ 173 IP12 |lo0 lo0 | IP22 174 IP11 | | IP21 175 SW1-------R1-----------------R2-------SW2 176 Links Group 178 Fig.1 CCDR framework in simple topology 180 4. CCDR Framework in Large Scale Topology 182 When the assured traffic spans across the large scale network, as 183 that illustrated in Fig.2, the Dual-BGP sessions cannot be 184 established hop by hop, especially for the iBGP within one AS. 186 For such scenario, we should consider to use the Route Reflector (RR) 187 to achieve the similar effect. Every edge router will establish two 188 BGP peer sessions with the RR via different loopback addresses 189 respectively. The other steps for traffic differentiation are same 190 as that described in the CCDR framework for simple topology. 192 As shown in Fig.2, if we select R3 as the RR, every edge router(R1 193 and R7 in this example) will build two BGP session with the RR. If 194 the PCE calculates select the dedicated path as R1-R2-R4-R7, then the 195 operator should set the explicit peer routes on these routers 196 respectively, pointing to the BGP next hop (loopback addresses of R1 197 and R7, which are used to send the prefix of the assured traffic) to 198 the selected forwarding address. 200 +----------R3(RR)------------+ 201 | | 202 SW1-------R1-------R5---------R6-------R7--------SW2 203 | | | | 204 +-------R2---------R4--------+ 206 Fig.2 CCDR framework in large scale network 208 5. CCDR Multi-BGP Strategy 210 In general situation, different applications may require different 211 QoS criteria, which may include: 213 o Traffic that requires low latency and is not sensitive to packet 214 loss. 216 o Traffic that requires low packet loss and can endure higher 217 latency. 219 o Traffic that requires low jitter. 221 These different traffic requirements can be summarized in the 222 following table: 224 +----------+-------------+---------------+-----------------+ 225 | Flow No. | Latency | Packet Loss | Jitter | 226 +----------+-------------+---------------+-----------------+ 227 | 1 | Low | Normal | Don't care | 228 +----------+-------------+---------------+-----------------+ 229 | 2 | Normal | Low | Dont't care | 230 +----------+-------------+---------------+-----------------+ 231 | 3 | Normal | Normal | Low | 232 +----------+-------------+---------------+-----------------+ 233 Table 1. Traffic Requirement Criteria 235 For Flow No.1, we can select the shortest distance path to carry the 236 traffic; for Flow No.2, we can select the path that is comprised by 237 underloading links from end to end; for Flow No.3, we can let all 238 assured traffic pass the determined single path, no ECMP distribution 239 on the parallel links is desired. 241 It is almost impossible to provide an end-to-end (E2E) path with 242 latency, jitter, packet loss constraints to meet the above 243 requirements in large scale IP-based network via the distributed 244 routing protocol, but these requirements can be solved with the 245 assistance of PCE controller, because the PCE has the overall network 246 view, can collect real network topology and network performance 247 information about the underlying network, select the appropriate path 248 to meet various network performance requirements of different 249 traffics. 251 6. CCDR Framework for Multi-BGP Strategy 253 The framework to implement the CCDR Multi-BGP strategy are the 254 followings: 256 o PCE gets topology and link utilization information from the 257 underlying network, calculates the appropriate path upon 258 application's requirements.. 260 o PCE sends the key parameters to edge/RR routers(R1, R7 and R3 in 261 Fig.3) to establish multi-BGP peer sessions and advertises 262 different prefixes via them. 264 o PCE sends the route information to the routers (R1,R2,R4,R7 in 265 Fig.3) on forwarding path via PCEP, to build the path to the BGP 266 next-hop of the advertised prefixes. 268 o If the assured traffic prefixes were changed but the total volume 269 of assured traffic does not exceed the physical capacity of the 270 previous end-to-end path, PCE needs only change the prefixed 271 advertised via the edge routers (R1,R7 in Fig.3). 273 o If the volume of assured traffic exceeds the capacity of previous 274 calculated path, PCE can recalculate the appropriate paths to 275 accommodate the exceeding traffic. After that, PCE needs to 276 update on-path routers to build the forwarding path hop by hop. 278 +----+ 279 ***********+ PCE+************* 280 * +--*-+ * 281 * / * \ * 282 * * * 283 PCEP* BGP-LS/SNMP *PCEP 284 * * * 285 * * \ * / 286 \ * / * \ */ 287 \*/-----------R3--------------* 288 | | 289 | | 290 SW1-------R1-------R5---------R6-------R7--------SW2 291 | | | | 292 | | | | 293 +-------R2---------R4--------+ 295 Fig.3 CCDR framework for Multi-BGP deployment 297 7. PCEP Extension for Key Parameters Delivery 299 The PCEP protocol needs to be extended to transfer the following key 300 parameters: 302 o Peer addresses pair that is used to build the BGP session 304 o Advertised prefixes and their associated BGP session. 306 o Explicit route information to BGP next hop of advertised prefixes. 308 Once the router receives such information, it should establish the 309 BGP session with the peer appointed in the PCEP message, advertise 310 the prefixes that contained in the corresponding PCEP message, and 311 build the end to end dedicated path hop by hop. 313 Details of communications between PCEP and BGP subsystems in router's 314 control plane are out of scope of this draft and will be described in 315 separate draft [I-D.ietf-pce-pcep-extension-native-ip] . 317 The reason that we selected PCEP as the southbound protocol instead 318 of OpenFlow, is that PCEP is suitable for the changes in control 319 plane of the network devices, while OpenFlow dramatically changes the 320 forwarding plane. We also think that the level of centralization 321 that requires by OpenFlow is hardly achievable in many today's SP 322 networks so hybrid BGP+PCEP approach looks much more interesting. 324 8. Deployment Consideration 326 8.1. Scalability 328 In CCDR framework, PCE needs only influence the edge routers for the 329 prefixes advertisement via the multi-BGP deployment. The route 330 information for these prefixes within the on-path routers were 331 distributed via the BGP protocol. 333 Unlike the solution from BGP Flowspec, the on-path router need only 334 keep the specific policy routes to the BGP next-hop of the 335 differentiate prefixes, not the specific routes to the prefixes 336 themselves. This can lessen the burden from the table size of policy 337 based routes for the on-path routers, and has more expandability when 338 comparing with the solution from BGP flowspec or Openflow. 340 8.2. High Availability 342 The CCDR framework is based on the distributed IP protocol. If the 343 PCE failed, the forwarding plane will not be impacted, as the BGP 344 session between all devices will not flap, and the forwarding table 345 will remain unchaned. 347 If one node on the optimal path is failed, the assurance traffic will 348 fall over to the best-effort forwarding path. One can even design 349 several assurance paths to load balance/hot-standby the assurance 350 traffic to meet the path failure situation, as done in MPLS FRR. 352 For high availability of PCE/SDN-controller, operator should rely on 353 existing HA solutions for SDN controller, such as clustering 354 technology and deployment. 356 8.3. Incremental deployment 358 Not every router within the network will support the PCEP extension 359 that defined in [I-D.ietf-pce-pcep-extension-native-ip] 360 simultaneously. 362 For such situations, router on the edge of domain can be upgraded 363 first, and then the traffic can be assured between different domains. 364 Within each domain, the traffic will be forwarded along the best- 365 effort path. Service provider can selectively upgrade the routers on 366 each domain in sequence. 368 9. Security Considerations 370 The PCE should have the capability to calculate the loop-free end to 371 end path upon the status of network condition and the service 372 requirements in real time. 374 The PCE need consider the explicit route deployment order (for 375 example, from tail router to head router) to eliminate the possible 376 transient traffic loop. 378 CCDR framework described in this draft puts more requirements on the 379 function of PCE and its communication with the underlay devices. 380 Service provider should consider more on the protection of SDN 381 controller and their communication with the underlay devices, which 382 is described in document [RFC5440] and 384 CCDR framework does not require the change of forward behavior on the 385 underlay devices, then there will no additional security impact on 386 the devices. 388 10. IANA Considerations 390 This document does not require any IANA actions. 392 11. Contributors 394 Penghui Mi and Shaofu Peng contribute the contents of this draft. 396 12. Acknowledgement 398 The author would like to thank Deborah Brungard, Adrian Farrel, 399 Huaimo Chen, Vishnu Beeram, Lou Berger, Dhruv Dhody and Jessica Chen 400 for their supports and comments on this draft. 402 13. Normative References 404 [I-D.ietf-pce-pcep-extension-native-ip] 405 Wang, A., Khasanov, B., Cheruathur, S., Zhu, C., and S. 406 Fang, "PCEP Extension for Native IP Network", draft-ietf- 407 pce-pcep-extension-native-ip-03 (work in progress), March 408 2019. 410 [I-D.ietf-teas-native-ip-scenarios] 411 Wang, A., Huang, X., Qou, C., Li, Z., and P. Mi, 412 "Scenario, Simulation and Suggestion of PCE in Native IP 413 Network", draft-ietf-teas-native-ip-scenarios-02 (work in 414 progress), October 2018. 416 [I-D.ietf-teas-pcecc-use-cases] 417 Zhao, Q., Li, Z., Khasanov, B., Dhody, D., Ke, Z., Fang, 418 L., Zhou, C., Communications, T., Rachitskiy, A., and A. 419 Gulida, "The Use Cases for Path Computation Element (PCE) 420 as a Central Controller (PCECC).", draft-ietf-teas-pcecc- 421 use-cases-03 (work in progress), March 2019. 423 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 424 Requirement Levels", BCP 14, RFC 2119, 425 DOI 10.17487/RFC2119, March 1997, 426 . 428 [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation 429 Element (PCE) Communication Protocol (PCEP)", RFC 5440, 430 DOI 10.17487/RFC5440, March 2009, 431 . 433 [RFC8253] Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody, 434 "PCEPS: Usage of TLS to Provide a Secure Transport for the 435 Path Computation Element Communication Protocol (PCEP)", 436 RFC 8253, DOI 10.17487/RFC8253, October 2017, 437 . 439 [RFC8283] Farrel, A., Ed., Zhao, Q., Ed., Li, Z., and C. Zhou, "An 440 Architecture for Use of PCE and the PCE Communication 441 Protocol (PCEP) in a Network with Central Control", 442 RFC 8283, DOI 10.17487/RFC8283, December 2017, 443 . 445 Authors' Addresses 447 Aijun Wang 448 China Telecom 449 Beiqijia Town, Changping District 450 Beijing 102209 451 China 453 Email: wangaj.bri@chinatelecom.cn 455 Quintin Zhao 456 Huawei Technologies 457 125 Nagog Technology Park 458 Acton, MA 01719 459 USA 461 Email: quintin.zhao@huawei.com 462 Boris Khasanov 463 Huawei Technologies 464 Moskovskiy Prospekt 97A 465 St.Petersburg 196084 466 Russia 468 Email: khasanov.boris@huawei.com 470 Huaimo Chen 471 Huawei Technologies 472 Boston, MA 473 USA 475 Email: huaimo.chen@huawei.com 477 Raghavendra Mallya 478 Juniper Networks 479 1133 Innovation Way 480 Sunnyvale, California 94089 481 USA 483 Email: rmallya@juniper.net