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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 RTGWG Working Group C. Li 3 Internet-Draft Z. Hu 4 Intended status: Standards Track Huawei Technologies 5 Expires: April 24, 2022 Y. Zhu 6 China Telecom 7 S. Hegde 8 Juniper Networks Inc. 9 October 21, 2021 11 Enhanced Topology Independent Loop-free Alternate Fast Re-route 12 draft-li-rtgwg-enhanced-ti-lfa-05 14 Abstract 16 Topology Independent Loop-free Alternate Fast Re-route (TI-LFA) aims 17 at providing protection of node and adjacency segments within the 18 Segment Routing (SR) framework. A key aspect of TI-LFA is the FRR 19 path selection approach establishing protection over the expected 20 post-convergence paths from the point of local repair. However, the 21 TI-LFA FRR path may skip the node even if it is specified in the SID 22 list to be traveled. 24 This document defines Enhanced TI-LFA(TI-LFA+) by adding a No-bypass 25 indicator for segments to ensure that the FRR route will not bypass 26 the specific node, such as firewall. Also, this document defines No- 27 bypass flag and No-FRR flag in SRH to indicate not to bypass nodes 28 and not to perform FRR on all the nodes along the SRv6 path, 29 respectively. 31 Status of This Memo 33 This Internet-Draft is submitted in full conformance with the 34 provisions of BCP 78 and BCP 79. 36 Internet-Drafts are working documents of the Internet Engineering 37 Task Force (IETF). Note that other groups may also distribute 38 working documents as Internet-Drafts. The list of current Internet- 39 Drafts is at https://datatracker.ietf.org/drafts/current/. 41 Internet-Drafts are draft documents valid for a maximum of six months 42 and may be updated, replaced, or obsoleted by other documents at any 43 time. It is inappropriate to use Internet-Drafts as reference 44 material or to cite them other than as "work in progress." 46 This Internet-Draft will expire on April 24, 2022. 48 Copyright Notice 50 Copyright (c) 2021 IETF Trust and the persons identified as the 51 document authors. All rights reserved. 53 This document is subject to BCP 78 and the IETF Trust's Legal 54 Provisions Relating to IETF Documents 55 (https://trustee.ietf.org/license-info) in effect on the date of 56 publication of this document. Please review these documents 57 carefully, as they describe your rights and restrictions with respect 58 to this document. Code Components extracted from this document must 59 include Simplified BSD License text as described in Section 4.e of 60 the Trust Legal Provisions and are provided without warranty as 61 described in the Simplified BSD License. 63 Table of Contents 65 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 66 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 67 2.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 68 3. Overview of Enhanced TI-LFA . . . . . . . . . . . . . . . . . 3 69 4. IGP Protocol Extensions . . . . . . . . . . . . . . . . . . . 4 70 4.1. IS-IS . . . . . . . . . . . . . . . . . . . . . . . . . . 4 71 4.2. OSPF . . . . . . . . . . . . . . . . . . . . . . . . . . 6 72 5. Flags in SRH . . . . . . . . . . . . . . . . . . . . . . . . 8 73 5.1. No-bypass Flag in SRH . . . . . . . . . . . . . . . . . . 8 74 5.2. No-FRR Flag in SRH . . . . . . . . . . . . . . . . . . . 9 75 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 76 7. Security Considerations . . . . . . . . . . . . . . . . . . . 9 77 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 78 8.1. Normative References . . . . . . . . . . . . . . . . . . 9 79 8.2. Informative References . . . . . . . . . . . . . . . . . 10 80 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 82 1. Introduction 84 Segment Routing [RFC8402] enables to steer packets by explicitly 85 encoding instructions in the data packets at the source node to 86 support services like traffic engineer. Relying on SR, 87 [I-D.ietf-rtgwg-segment-routing-ti-lfa] defines Topology Independent 88 Loop-free Alternate Fast Re-route (TI-LFA), a local repair mechanism 89 for IGP shortest path that capable of restoring end-to-end 90 connectivity in the case of a sudden directly connected failure of a 91 network component. 93 TI-LFA supports to establish a loop free backup path over the 94 expected post-convergence paths from the point of local repair 95 irrespective of the topologies used in the network, which provides a 96 major improvment compared to LFA [RFC5286], and remote LFA [RFC7490] 97 which cannot be applicable in some topologies [RFC6571]. 99 However, the TI-LFA path may skip the node that the active SID points 100 to when protecting [Adjacency, Node] segment lists. For instance, 101 the node that a adjacency SID points to is a very important node and 102 can not be skipped, such as a firewall node. When the link between 103 the local repair node and firewall node fails, the packets should be 104 steered back to the firewall and then forwarding. But in TI-LFA, if 105 the next SID in the SID list is a node SID, the TI-LFA FRR path MAY 106 bypass the node that the active segment points to. Also, if the 107 firewall node is down, the packets should be dropped instead for fast 108 reroute to bypass the node. Bypassing nodes like firewall in FRR 109 brings issues of network security and reliability. 111 To enhance the security and reliability of networks, this document 112 defines an Enhanced Topology Independent Loop-free Alternate Fast Re- 113 route (TI-LFA+) based on TI-LFA by adding a No-bypass flag for 114 segments to explicitly specify what node can not be bypassed. Also, 115 this document defines No-bypass flag and No-FRR flag in SRH to 116 indicate not to bypass nodes and not to perform FRR on all the nodes 117 along the SRv6 path, respectively. 119 2. Terminology 121 This document makes use of the terms defined in 122 [I-D.ietf-rtgwg-segment-routing-ti-lfa] and [RFC8402]. The reader is 123 assumed to be familiar with the terminology defined in 124 [I-D.ietf-rtgwg-segment-routing-ti-lfa] and [RFC8402]. 126 2.1. Requirements Language 128 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 129 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 130 "OPTIONAL" in this document are to be interpreted as described in BCP 131 14 [RFC2119] [RFC8174] when, and only when, they appear in all 132 capitals, as shown here. 134 3. Overview of Enhanced TI-LFA 136 Enhanced Topology Independent Loop-free Alternate Fast Re-route (TI- 137 LFA+) is an enhancement of TI-LFA to explicitly indicate whether a 138 node that segment points to can not be bypassed in FRR scenarios. 140 TI-LFA+ will not change the main process and algorithm of TI-LFA. 141 Instead, in TI-LFA+, when generating repair SID list for a SID, the 142 node should consider whether the SID endpoint can be baseed or not, 143 which is explicitly encoded in IGP messages. If the node that 144 segment points to can not be bypassed, then the repair SID MUST lead 145 the packets to that node. This document defines a No-bypass flag for 146 segments in IS-IS and OSPF. Details will be discussed in section 4. 148 A node should advertise two kinds of segment to meet various service 149 policy requirements. 151 o Bypassing capable segment with No-bypass flag unset 153 o No-bypassing segment with No-bypass flag set. 155 A controller or control plane should choose specific segment 156 according to the service policy. 158 [Editors' note] If the TI-LFA result is generated based on Locator 159 route instead of SIDs, then the No-bypass Flag can be applied to the 160 Locator. 162 Also, this document defines No-bypass flag and No-FRR flag in SRH to 163 indicate not to bypass nodes and not to perform FRR on all the nodes 164 along the SRv6 path, respectively. Details will be discussed in 165 section 5. 167 4. IGP Protocol Extensions 169 4.1. IS-IS 171 [RFC8667] describes the necessary IS-IS extensions that need to be 172 introduced for Segment Routing.[I-D.ietf-lsr-isis-srv6-extensions] 173 defines the IS-IS extensions required to support Segment Routing over 174 an IPv6 data plane. This documment defines a No-bypass flag in flag 175 filed of the following IS-IS sub-TLV/TLV. 177 o Prefix Segment Identifier sub-TLV (Prefix-SID sub-TLV) [RFC8667] 179 o Adjacency Segment Identifier sub- TLV (Adj-SID sub-TLV).[RFC8667] 181 o Locator entry in SRv6 Locator TLV 182 [I-D.ietf-lsr-isis-srv6-extensions] 184 The following figures are included here for reference and will be 185 deleted in the future version. 187 0 1 2 3 188 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 1 189 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 190 | Type | Length | Flags | Algorithm | 191 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 192 | SID/Index/Label (variable) | 193 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 195 0 1 2 3 4 5 6 7 196 +--+--+--+--+--+--+--+--+ 197 |R | N| P| E| V| L|NB| | 198 +--+--+--+--+--+--+--+--+ 200 Figure 1. Prefix-SID sub-TLV and No-bypass Flag 202 0 1 2 3 203 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 1 204 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 205 | Type | Length | Flags | Weight | 206 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 207 | SID/Label/Index (variable) | 208 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 210 0 1 2 3 4 5 6 7 211 +--+--+--+--+--+--+--+--+ 212 |F | B| V| L| S|NB| | | 213 +--+--+--+--+--+--+--+--+ 214 Figure 2. Adj-SID sub-TLV and No-bypass Flag 216 0 1 2 3 217 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 1 218 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 219 | Metric | 220 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 221 | Flags | Algorithm | 222 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 223 | Loc Size | Locator (variable)... 224 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 225 | Sub-tlv-len | Sub-TLVs (variable) . . . | 226 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 228 0 1 2 3 4 5 6 7 229 +--+--+--+--+--+--+--+--+ 230 |D |NB| | | | | | | 231 +--+--+--+--+--+--+--+--+ 232 Figure 3. SRv6 Locator Entry and No-bypass Flag 234 If the No-bypass(NB) flag is set, means the node that the SID/Label/ 235 Locator points to can not be bypassed. Oterwise, the node can be 236 bypassed. 238 4.2. OSPF 240 [RFC8665] describes the necessary OSPF extensions that need to be 241 introduced for Segment Routing.[I-D.ietf-lsr-ospfv3-srv6-extensions] 242 defines the OSPF extensions required to support Segment Routing over 243 an IPv6 data plane. This documment defines a No-bypass flag in flag 244 filed of the following OSPF sub-TLV/TLV. 246 o Prefix SID Sub-TLV [RFC8665] 248 o Adj-SID sub-TLV [RFC8665] 250 o SRv6 Node SID TLV [I-D.ietf-lsr-ospfv3-srv6-extensions] 252 o SRv6 SID Link Attribute Sub-TLV 253 [I-D.ietf-lsr-ospfv3-srv6-extensions] 255 The following figures are included here for reference and will be 256 deleted in the future version. 258 0 1 2 3 259 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 1 260 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 261 | Type | Length | 262 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 263 | Flags | Reserved | MT-ID | Algorithm | 264 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 265 | SID/Index/Label (variable) | 266 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 268 0 1 2 3 4 5 6 7 269 +--+--+--+--+--+--+--+--+ 270 | |NP|M |E |V |L |NB| | 271 +--+--+--+--+--+--+--+--+ 273 Figure 4. Prefix-SID sub-TLV and No-bypass Flag 275 0 1 2 3 276 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 1 277 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 278 | Type | Length | 279 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 280 | Flags | Reserved | MT-ID | Weight | 281 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 282 | SID/Label/Index (variable) | 283 +---------------------------------------------------------------+ 285 0 1 2 3 4 5 6 7 286 +--+--+--+--+--+--+--+--+ 287 |B | V| L| G| P|NB| | | 288 +--+--+--+--+--+--+--+--+ 290 Figure 5. Adj-SID sub-TLV and No-bypass Flag 292 0 1 2 3 293 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 1 294 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 295 | Type | Length | 296 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 297 | Reserved | Function-Flags| Function Code | 298 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 299 | Reserved | SID Flags | SID-size | 300 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 301 | SID (variable - 32 bit aligned) ... 302 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 303 | Sub-TLVs (variable) . . . 304 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 306 0 1 2 3 4 5 6 7 307 +--+--+--+--+--+--+--+--+ 308 |D |NB| | | | | | | 309 +--+--+--+--+--+--+--+--+ 310 Figure 6. SRv6 Node SID TLV and No-bypass Flag 312 0 1 2 3 313 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 1 314 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 315 | Type | Length | 316 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 317 | Reserved | Function-Flags| Function Code | 318 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 319 | Reserved | SID Flags | SID-size | 320 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 321 | SID (variable - 32 bit aligned) ... 322 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 323 | Sub-TLVs (variable) . . . 324 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 326 0 1 2 3 4 5 6 7 327 +--+--+--+--+--+--+--+--+ 328 |NB| | | | | | | | 329 +--+--+--+--+--+--+--+--+ 330 Figure 7. SRv6 Adj-SID TLV and No-bypass Flag 332 If the No-bypass(NB) flag is set, means the node that the SID/Label/ 333 Locator points to can not be bypassed. Oterwise, the node can be 334 bypassed. 336 5. Flags in SRH 338 This section describes two flags in SRH. 340 5.1. No-bypass Flag in SRH 342 This document defines a No-bypass Flag in SRH [RFC8754]. 344 0 1 2 3 4 5 6 7 345 +--+--+--+--+--+--+--+--+ 346 |NB| | | | | | | | 347 +--+--+--+--+--+--+--+--+ 349 o NB Flag: No-Bypass flag, when the flag is set, the repair segment 350 endpoint nodes MUST NOT bypass any nodes when link or node 351 failures occur. When a link is down, the packet MUST be forwarded 352 to the next segment endpoint node through the repair path. When 353 the node identified by the active SID in IPv6 destination address 354 is down, the SID can not be skipped, and the traffic MUST be 355 forwarded to the node. 357 The flag can be set when the SID list containing service SIDs like 358 firewall SID, so that the traffic will not bypass the service nodes. 360 5.2. No-FRR Flag in SRH 362 This document defines a No-FRR Flag in SRH [RFC8754]. 364 0 1 2 3 4 5 6 7 365 +--+--+--+--+--+--+--+--+ 366 | |NF| | | | | | | 367 +--+--+--+--+--+--+--+--+ 369 o NF Flag: No-FRR flag, when the flag is set, the FRR is disable for 370 the packet, thus the packet will not be protected by the Local 371 protection mechanism, such as TI-LFA. 373 The flag can be set when the SID list containing service SIDs like 374 firewall SID, so that the traffic will not bypass the service nodes. 375 In this case, E2E protection mechanism should be deployed. 377 6. IANA Considerations 379 TBD. 381 7. Security Considerations 383 TBD. 385 8. References 387 8.1. Normative References 389 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 390 Requirement Levels", BCP 14, RFC 2119, 391 DOI 10.17487/RFC2119, March 1997, 392 . 394 [RFC5286] Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for 395 IP Fast Reroute: Loop-Free Alternates", RFC 5286, 396 DOI 10.17487/RFC5286, September 2008, 397 . 399 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 400 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 401 May 2017, . 403 [RFC7490] Bryant, S., Filsfils, C., Previdi, S., Shand, M., and N. 404 So, "Remote Loop-Free Alternate (LFA) Fast Reroute (FRR)", 405 RFC 7490, DOI 10.17487/RFC7490, April 2015, 406 . 408 [RFC6571] Filsfils, C., Ed., Francois, P., Ed., Shand, M., Decraene, 409 B., Uttaro, J., Leymann, N., and M. Horneffer, "Loop-Free 410 Alternate (LFA) Applicability in Service Provider (SP) 411 Networks", RFC 6571, DOI 10.17487/RFC6571, June 2012, 412 . 414 [I-D.ietf-rtgwg-segment-routing-ti-lfa] 415 Litkowski, S., Bashandy, A., Filsfils, C., Francois, P., 416 Decraene, B., and D. Voyer, "Topology Independent Fast 417 Reroute using Segment Routing", draft-ietf-rtgwg-segment- 418 routing-ti-lfa-07 (work in progress), June 2021. 420 [RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J., 421 Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header 422 (SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020, 423 . 425 8.2. Informative References 427 [RFC4657] Ash, J., Ed. and J. Le Roux, Ed., "Path Computation 428 Element (PCE) Communication Protocol Generic 429 Requirements", RFC 4657, DOI 10.17487/RFC4657, September 430 2006, . 432 [RFC8253] Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody, 433 "PCEPS: Usage of TLS to Provide a Secure Transport for the 434 Path Computation Element Communication Protocol (PCEP)", 435 RFC 8253, DOI 10.17487/RFC8253, October 2017, 436 . 438 [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., 439 Decraene, B., Litkowski, S., and R. Shakir, "Segment 440 Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, 441 July 2018, . 443 [RFC8667] Previdi, S., Ed., Ginsberg, L., Ed., Filsfils, C., 444 Bashandy, A., Gredler, H., and B. Decraene, "IS-IS 445 Extensions for Segment Routing", RFC 8667, 446 DOI 10.17487/RFC8667, December 2019, 447 . 449 [RFC8665] Psenak, P., Ed., Previdi, S., Ed., Filsfils, C., Gredler, 450 H., Shakir, R., Henderickx, W., and J. Tantsura, "OSPF 451 Extensions for Segment Routing", RFC 8665, 452 DOI 10.17487/RFC8665, December 2019, 453 . 455 [I-D.ietf-lsr-ospfv3-srv6-extensions] 456 Li, Z., Hu, Z., Cheng, D., Talaulikar, K., and P. Psenak, 457 "OSPFv3 Extensions for SRv6", draft-ietf-lsr- 458 ospfv3-srv6-extensions-02 (work in progress), February 459 2021. 461 [I-D.ietf-lsr-isis-srv6-extensions] 462 Psenak, P., Filsfils, C., Bashandy, A., Decraene, B., and 463 Z. Hu, "IS-IS Extensions to Support Segment Routing over 464 IPv6 Dataplane", draft-ietf-lsr-isis-srv6-extensions-18 465 (work in progress), October 2021. 467 Authors' Addresses 469 Cheng Li 470 Huawei Technologies 471 Huawei Campus, No. 156 Beiqing Rd. 472 Beijing 100095 473 China 475 Email: c.l@huawei.com 477 Zhibo Hu 478 Huawei Technologies 479 Huawei Campus, No. 156 Beiqing Rd. 480 Beijing 100095 481 China 483 Email: huzhibo@huawei.com 485 Yongqing Zhu 486 China Telecom 488 Email: zhuyq8@chinatelecom.cn 489 Shraddha Hegde 490 Juniper Networks Inc. 491 India 493 Email: shraddha@juniper.net