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Checking references for intended status: Experimental ---------------------------------------------------------------------------- == Unused Reference: 'I-D.ietf-teas-pcecc-use-cases' is defined on line 399, but no explicit reference was found in the text == Outdated reference: A later version (-30) exists of draft-ietf-pce-pcep-extension-native-ip-01 == Outdated reference: A later version (-12) exists of draft-ietf-teas-native-ip-scenarios-01 == Outdated reference: A later version (-13) exists of draft-ietf-teas-pcecc-use-cases-02 Summary: 1 error (**), 0 flaws (~~), 6 warnings (==), 2 comments (--).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: April 24, 2019 B. Khasanov 6 H. Chen 7 Huawei Technologies 8 R. Mallya 9 Juniper Networks 10 October 21, 2018 12 PCE in Native IP Network 13 draft-ietf-teas-pce-native-ip-02 15 Abstract 17 This document defines the CCDR framework for traffic engineering 18 within native IP network, using Dual/Multi-BGP session strategy and 19 PCE-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 CCDR traffic engineering is 22 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 April 24, 2019. 41 Copyright Notice 43 Copyright (c) 2018 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. Dual-BGP Framework for Simple Topology . . . . . . . . . . . 3 61 4. Dual-BGP Framework in Large Scale Topology . . . . . . . . . 4 62 5. Multi-BGP Strategy for Extended Traffic Differentiation . . . 5 63 6. CCDR Procedures for Multi-BGP Strategy . . . . . . . . . . . 6 64 7. PCEP Extension for Key Parameters Delivery . . . . . . . . . 7 65 8. Deployment Consideration . . . . . . . . . . . . . . . . . . 7 66 8.1. Scalability . . . . . . . . . . . . . . . . . . . . . . . 8 67 8.2. High Availability . . . . . . . . . . . . . . . . . . . . 8 68 8.3. Incremental deployment . . . . . . . . . . . . . . . . . 8 69 9. Security Considerations . . . . . . . . . . . . . . . . . . . 8 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 scenario and 79 simulation results for traffic engineering in native IP network. In 80 summary, the requirements for traffic engineering in native IP 81 network are the followings: 83 o No complex MPLS signaling procedure. 85 o End to End traffic assurance, determined QoS behavior. 87 o Identical deployment method for intra- and inter- domain. 89 o No influence to existing router forward behavior. 91 o Can utilize the power of centrally control(PCE) and flexibility/ 92 robustness of distributed control protocol. 94 o Coping with the differentiation requirements for large amount 95 traffic and prefixes. 97 o Flexible deployment and automation control. 99 This document defines the framework for traffic engineering within 100 native IP network, using Dual/Multi-BGP session strategy, to meet the 101 above requirements in dynamical and central control mode. The 102 related PCEP protocol extensions to transfer the key parameters 103 between PCE and the underlying network devices(PCC) are provided in 104 draft [I-D.ietf-pce-pcep-extension-native-ip]. 106 2. Conventions used in this document 108 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 109 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 110 document are to be interpreted as described in RFC 2119 [RFC2119] . 112 3. Dual-BGP Framework for Simple Topology 114 Dual-BGP framework for simple topology is illustrated in Fig.1, which 115 is comprised by SW1, SW2, R1, R2. There are multiple physical links 116 between R1 and R2. Traffic between IP11 and IP21 is normal traffic, 117 traffic between IP12 and IP22 is priority traffic that should be 118 treated differently. 120 Only native IGP/BGP protocol is deployed between R1 and R2. The 121 traffic between each address pair may change timely and the 122 corresponding source/destination addresses of the traffic may also 123 change dynamically. 125 The key ideas of the Dual-BGP framework for this simple topology are 126 the followings: 128 o Build two BGP sessions between R1 and R2, via the different 129 loopback address lo0, lo1 on these routers. 131 o Send different prefixes via the two BGP sessions. (For example, 132 IP11/IP21 via the BGP pair 1 and IP12/IP22 via the BGP pair 2). 134 o Set the explicit peer route on R1 and R2 respectively for BGP next 135 hop of lo0, lo1 to different physical link address between R1 and 136 R2. 138 The traffic between the IP11 and IP21, and the traffic between IP12 139 and IP22 will go through different physical links between R1 and R2, 140 each type of traffic occupy different dedicated physical links. 142 If there is more traffic between IP12 and IP22 that needs to be 143 assured , one can add more physical links between R1 and R2 to reach 144 the loopback address lo1(also the next hop for BGP Peer pair2). In 145 this cases the prefixes that advertised by two BGP peers need not be 146 changed. 148 If, for example, there is traffic from another address pair that 149 needs to be assured (for example IP13/IP23), and the total volume of 150 assured traffic does not exceed the capacity of the previous 151 appointed physical links, one need only to advertise the newly added 152 source/destination prefixes via the BGP peer pair2. The traffic 153 between IP13/IP23 will go through the assigned dedicated physical 154 links as the traffic between IP12/IP22. 156 Such decouple philosophy gives network operator flexible control 157 ability on the network traffic, achieve the determined QoS assurance 158 effect to meet the application's requirement. No complex MPLS signal 159 procedures is introduced, the router need only support native IP 160 protocol. 162 | BGP Peer Pair2 | 163 +------------------+ 164 |lo1 lo1 | 165 | | 166 | BGP Peer Pair1 | 167 +------------------+ 168 IP12 |lo0 lo0 | IP22 169 IP11 | | IP21 170 SW1-------R1-----------------R2-------SW2 171 Links Group 173 Fig.1 Design Philosophy for Dual-BGP Framework 175 4. Dual-BGP Framework in Large Scale Topology 177 When the assured traffic spans across one large scale network, as 178 that illustrated in Fig.2, the dual BGP sessions cannot be 179 established hop by hop especially for the iBGP within one AS. 181 For such scenario, we should consider to use the Route Reflector (RR) 182 to achieve the similar Dual-BGP effect, select one router which 183 performs the role of RR (for example R3 in Fig.2), every other edge 184 router will establish two BGP peer sessions with the RR, using their 185 different loopback addresses respectively. The other two steps for 186 traffic differentiation are same as that described in the Dual-BGP 187 simple topology usage case. 189 For the example shown in Fig.2, if we select the R1-R2-R4-R7 as the 190 dedicated path, then we should set the explicit peer routes on these 191 routers respectively, pointing to the BGP next hop (loopback 192 addresses of R1 and R7, which are used to send the prefix of the 193 assured traffic) to the actual address of the physical link. 195 +------------R3--------------+ 196 | | 197 SW1-------R1-------R5---------R6-------R7--------SW2 198 | | | | 199 +-------R2---------R4--------+ 201 Fig.2 Dual-BGP Framework for Large Scale Network 203 5. Multi-BGP Strategy for Extended Traffic Differentiation 205 In general situation, several additional traffic differentiation 206 criteria exist, including: 208 o Traffic that requires low latency links and is not sensitive to 209 packet loss. 211 o Traffic that requires low packet loss but can endure higher 212 latency. 214 o Traffic that requires lowest jitter path. 216 These different traffic requirements can be summarized in the 217 following table: 219 +----------+-------------+---------------+-----------------+ 220 | Flow No. | Latency | Packet Loss | Jitter | 221 +----------+-------------+---------------+-----------------+ 222 | 1 | Low | Normal | Don't care | 223 +----------+-------------+---------------+-----------------+ 224 | 2 | Normal | Low | Dont't care | 225 +----------+-------------+---------------+-----------------+ 226 | 3 | Normal | Normal | Low | 227 +----------+-------------+---------------+-----------------+ 228 Table 1. Traffic Requirement Criteria 230 For Flow No.1, we can select the shortest distance path to carry the 231 traffic; for Flow No.2, we can select the idle links to form its end 232 to end path; for Flow No.3, we can let all assured traffic pass one 233 single path, no ECMP distribution on the parallel links is required. 235 It is almost impossible to provide an end-to-end (E2E) path with 236 latency, jitter, packet loss constraints to meet the above 237 requirements in large scale IP-based network via the distributed 238 routing protocol, but these requirements can be solved using the CCDR 239 framework since the PCE has the overall network view, can collect 240 real network topology and network performance information about the 241 underlying network, select the appropriate path to meet various 242 network performance requirements of different traffic. 244 6. CCDR Procedures for Multi-BGP Strategy 246 The procedures to implement the Multi-BGP strategy are the 247 followings: 249 o PCE gets topology and link utilization information from the 250 underlying network, calculates the appropriate link path upon 251 application's requirements.. 253 o PCE sends the key parameters to edge/RR routers(R1, R7 and R3 in 254 Fig.3) to build multi-BGP peer relations and advertises different 255 prefixes via them. 257 o PCE sends the route information to the routers (R1,R2,R4,R7 in 258 Fig.3) on forwarding path via PCEP, to build the path to the BGP 259 next-hop of the advertised prefixes. 261 o If the assured traffic prefixes were changed but the total volume 262 of assured traffic does not exceed the physical capacity of the 263 previous end-to-end path, then PCE needs only change the related 264 information on edge routers (R1,R7 in Fig.3). 266 o If the volume of assured traffic exceeds the capacity of previous 267 calculated path, PCE must recalculate the appropriate path to 268 accommodate the exceeding traffic via some new end-to-end physical 269 links. After that PCE needs to update on-path routers to build 270 such path hop by hop. 272 +----+ 273 ***********+ PCE+************* 274 * +--*-+ * 275 * / * \ * 276 * * * 277 PCEP* BGP-LS/SNMP *PCEP 278 * * * 279 * * \ * / 280 \ * / * \ */ 281 \*/-----------R3--------------* 282 | | 283 | | 284 SW1-------R1-------R5---------R6-------R7--------SW2 285 | | | | 286 | | | | 287 +-------R2---------R4--------+ 289 Fig.3 PCE based framework for Multi-BGP deployment 291 7. PCEP Extension for Key Parameters Delivery 293 The PCEP protocol needs to be extended to transfer the following key 294 parameters: 296 o BGP peer address and advertised prefixes. 298 o Explicit route information to BGP next hop of advertised prefixes. 300 Once the router receives such information, it should establish the 301 BGP session with the peer appointed in the PCEP message, advertise 302 the prefixes that contained in the corresponding PCEP message, and 303 build the end to end dedicated path hop by hop. Details of 304 communications between PCEP and BGP subsystems in router's control 305 plane are out of scope of this draft and will be described in 306 separate draft [I-D.ietf-pce-pcep-extension-native-ip] . 308 The reason that we selected PCEP as the southbound protocol instead 309 of OpenFlow, is that PCEP is suitable for the changes in control 310 plane of the network devices, there OpenFlow dramatically changes the 311 forwarding plane. We also think that the level of centralization 312 that requires by OpenFlow is hardly achievable in many today's SP 313 networks so hybrid BGP+PCEP approach looks much more interesting. 315 8. Deployment Consideration 316 8.1. Scalability 318 In CCDR framework, PCE needs only to influence the edge routers for 319 the prefixes differentiation via the multi-BGP deployment. The route 320 information for these prefixes within the on-path routers were 321 distributed via the BGP protocol. Unlike the solution from BGP 322 Flowspec, the on-path router need only keep the specific policy 323 routes to the BGP next-hop of the differentiate prefixes, not the 324 specific routes to the prefixes themselves. This can lessen the 325 burden from the table size of policy based routes for the on-path 326 routers, and has more scalabilities when comparing with the solution 327 from BGP flowspec or Openflow. 329 8.2. High Availability 331 CCDR framework is based on the distributed IP protocol. If the PCE 332 failed, the forwarding plane will not be impacted, as the BGP session 333 between all devices will not flap, and the forwarding table will 334 remain the same. If one node on the optimal path is failed, the 335 assurance traffic will fall over to the best-effort forwarding path. 336 One can even design several assurance paths to load balance/hot 337 standby the assurance traffic to meet the path failure situation, as 338 done in MPLS FRR. 340 For high availability of PCE/SDN-controller, operator should rely on 341 existing HA solutions for SDN controller, such as clustering 342 technology and deployment. 344 8.3. Incremental deployment 346 Not every router within the network support will support the PCEP 347 extension that defined in [I-D.ietf-pce-pcep-extension-native-ip] 348 simultaneously. For such situations, router on the edge of domain 349 can be upgraded first, and then the traffic can be assured between 350 different domains. Within each domain, the traffic will be forwarded 351 along the best-effort path. Service provider can selectively upgrade 352 the routers on each domain in sequence. 354 9. Security Considerations 356 Solution described in this draft puts more requirements on the 357 function of PCE and its communication with the underlay devices. The 358 PCE should have the capability to calculate the loop-free e2e path 359 upon the status of network condition and the service requirements in 360 real time. The PCE need also to consider the router order during 361 deployment to eliminate the possible transient traffic loop. 363 This solution does not require the change of forward behavior on the 364 underlay devices, then there will no additional security impact for 365 the devices. 367 When deploy the solution on network, service provider should also 368 consider more on the protection of SDN controller and their 369 communication with the underlay devices, which is described in 370 document [RFC5440] and [RFC8253] 372 10. IANA Considerations 374 This document does not require any IANA actions. 376 11. Contributors 378 Penghui Mi and Shaofu Peng contribute the contents of this draft. 380 12. Acknowledgement 382 The author would like to thank Deborah Brungard, Adrian Farrel, 383 Huaimo Chen, Vishnu Beeram, Lou Berger, Dhruv Dhody and Jessica Chen 384 for their supports and comments on this draft. 386 13. Normative References 388 [I-D.ietf-pce-pcep-extension-native-ip] 389 Wang, A., Khasanov, B., Cheruathur, S., and C. Zhu, "PCEP 390 Extension for Native IP Network", draft-ietf-pce-pcep- 391 extension-native-ip-01 (work in progress), June 2018. 393 [I-D.ietf-teas-native-ip-scenarios] 394 Wang, A., Huang, X., Qou, C., Li, Z., Huang, L., and P. 395 Mi, "CCDR Scenario, Simulation and Suggestion", draft- 396 ietf-teas-native-ip-scenarios-01 (work in progress), June 397 2018. 399 [I-D.ietf-teas-pcecc-use-cases] 400 Zhao, Q., Li, Z., Khasanov, B., Dhody, D., Ke, Z., Fang, 401 L., Zhou, C., Communications, T., Rachitskiy, A., and A. 402 Gulida, "The Use Cases for Path Computation Element (PCE) 403 as a Central Controller (PCECC).", draft-ietf-teas-pcecc- 404 use-cases-02 (work in progress), October 2018. 406 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 407 Requirement Levels", BCP 14, RFC 2119, 408 DOI 10.17487/RFC2119, March 1997, 409 . 411 [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation 412 Element (PCE) Communication Protocol (PCEP)", RFC 5440, 413 DOI 10.17487/RFC5440, March 2009, 414 . 416 [RFC8253] Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody, 417 "PCEPS: Usage of TLS to Provide a Secure Transport for the 418 Path Computation Element Communication Protocol (PCEP)", 419 RFC 8253, DOI 10.17487/RFC8253, October 2017, 420 . 422 [RFC8283] Farrel, A., Ed., Zhao, Q., Ed., Li, Z., and C. Zhou, "An 423 Architecture for Use of PCE and the PCE Communication 424 Protocol (PCEP) in a Network with Central Control", 425 RFC 8283, DOI 10.17487/RFC8283, December 2017, 426 . 428 Authors' Addresses 430 Aijun Wang 431 China Telecom 432 Beiqijia Town, Changping District 433 Beijing 102209 434 China 436 Email: wangaj.bri@chinatelecom.cn 438 Quintin Zhao 439 Huawei Technologies 440 125 Nagog Technology Park 441 Acton, MA 01719 442 USA 444 Email: quintin.zhao@huawei.com 446 Boris Khasanov 447 Huawei Technologies 448 Moskovskiy Prospekt 97A 449 St.Petersburg 196084 450 Russia 452 Email: khasanov.boris@huawei.com 453 Huaimo Chen 454 Huawei Technologies 455 Boston, MA 456 USA 458 Email: huaimo.chen@huawei.com 460 Raghavendra Mallya 461 Juniper Networks 462 1133 Innovation Way 463 Sunnyvale, California 94089 464 USA 466 Email: rmallya@juniper.net