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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Unused Reference: 'I-D.ietf-bess-evpn-inter-subnet-forwarding' is defined on line 532, but no explicit reference was found in the text == Outdated reference: A later version (-15) exists of draft-ietf-bess-evpn-inter-subnet-forwarding-09 Summary: 1 error (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 IDR Working Group W. Wang 3 Internet-Draft A. Wang 4 Intended status: Standards Track China Telecom 5 Expires: February 25, 2021 H. Wang 6 Huawei Technologies 7 G. Mishra 8 Verizon Inc. 9 S. Zhuang 10 J. Dong 11 Huawei Technologies 12 August 24, 2020 14 Route Distinguisher Outbound Route Filter (RD-ORF) for BGP-4 15 draft-wang-idr-rd-orf-03 17 Abstract 19 This draft defines a new Outbound Route Filter (ORF) type, called the 20 Route Distinguisher ORF (RD-ORF). RD-ORF is applicable when the 21 routers do not exchange VPN routing information directly (e.g. 22 routers in single-domain connect via Route Reflector, or routers in 23 Option B/Option AB/Option C cross-domain scenario). 25 Status of This Memo 27 This Internet-Draft is submitted in full conformance with the 28 provisions of BCP 78 and BCP 79. 30 Internet-Drafts are working documents of the Internet Engineering 31 Task Force (IETF). Note that other groups may also distribute 32 working documents as Internet-Drafts. The list of current Internet- 33 Drafts is at https://datatracker.ietf.org/drafts/current/. 35 Internet-Drafts are draft documents valid for a maximum of six months 36 and may be updated, replaced, or obsoleted by other documents at any 37 time. It is inappropriate to use Internet-Drafts as reference 38 material or to cite them other than as "work in progress." 40 This Internet-Draft will expire on February 25, 2021. 42 Copyright Notice 44 Copyright (c) 2020 IETF Trust and the persons identified as the 45 document authors. All rights reserved. 47 This document is subject to BCP 78 and the IETF Trust's Legal 48 Provisions Relating to IETF Documents 49 (https://trustee.ietf.org/license-info) in effect on the date of 50 publication of this document. Please review these documents 51 carefully, as they describe your rights and restrictions with respect 52 to this document. Code Components extracted from this document must 53 include Simplified BSD License text as described in Section 4.e of 54 the Trust Legal Provisions and are provided without warranty as 55 described in the Simplified BSD License. 57 Table of Contents 59 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 60 2. Conventions used in this document . . . . . . . . . . . . . . 4 61 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 62 4. RD-ORF Encoding . . . . . . . . . . . . . . . . . . . . . . . 5 63 5. Application in single-domain scenario . . . . . . . . . . . . 7 64 5.1. Addition of RD-ORF entries . . . . . . . . . . . . . . . 7 65 5.1.1. Operation process of RD-ORF mechanism on source PE . 7 66 5.1.2. Operation process of RD-ORF mechanism on RR . . . . . 8 67 5.1.3. Operation process of RD-ORF mechanism on target PE . 8 68 5.2. Withdraw of RD-ORF entries . . . . . . . . . . . . . . . 9 69 6. Applications in cross-domain scenarios . . . . . . . . . . . 9 70 6.1. Application in Option B/Option AB cross-domain scenario . 9 71 6.2. Application in Option C cross-domain scenario . . . . . . 10 72 7. Security Considerations . . . . . . . . . . . . . . . . . . . 11 73 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 74 9. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 12 75 10. Normative References . . . . . . . . . . . . . . . . . . . . 12 76 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 78 1. Introduction 80 With the rapid growth of network scale, Route Reflector is introduced 81 in order to reduce the network complexity. Routers in the same 82 Autonomous System only need to establish iBGP session with RR to 83 transmit routes. 85 In VPN scenario shown in Figure 1, PE1 - PE4 establish IBGP sessions 86 with RR to ensure the routes can be transmitted within AS100, where 87 PE1 and PE3 maintain VRFs of VPN1 and VPN2, PE2 maintains VPN1's VRF 88 and PE4 maintains VPN2's VRF. RR don not maintain any VRFs. 90 +----------------------------------------------+ 91 | | 92 | | 93 | +---------+ +---------+ | 94 | | PE1 | | PE4 | | 95 | +---------+ +---------+ | 96 | VPN1 \ / VPN2 | 97 | VPN2 \+---------+ / | 98 | | | | 99 | | RR | | 100 | | | | 101 | +---------+ \ | 102 | / \ | 103 | +---------+/ +---------+ | 104 | | PE2 | | PE3 | | 105 | +---------+ +---------+ | 106 | VPN1 VPN1 | 107 | AS 100 VPN2 | 108 +----------------------------------------------+ 110 Figure 1: Single-domain scenario 112 When the VRF of VPN1 in PE1 overflows, due to PE1 and other PEs are 113 not iBGP neighbors, BGP Maximum Prefix Features cannot work, so the 114 problem on PE2 cannot be known. 116 Now, there are several solutions can be used to alleviate this 117 problem: 119 o Route Target Constraint (RTC) as defined in [RFC4684] 121 o Address Prefix ORF as defined in [RFC5292] 123 o PE-CE edge peer Maximum Prefix 125 o Configure the Maximum Prefix for each VRF on edge nodes 127 However, there are limitations to existing solutions: 129 1) Route Target Constraint 131 RTC can only filter the VPN routes from the uninterested VRFs, if the 132 "trashing routes" come from the interested VRF, filter on RTs will 133 erase all prefixes from this VRF. 135 2) Address Prefix ORF 136 Using Address Prefix ORF to filter VPN routes need to pre- 137 configuration, but it is impossible to know which prefix may cause 138 overflow in advance. 140 3) PE-CE edge peer Maximum Prefix 142 This mechanism can only protect the edge between PE-CE, it can't be 143 deployed within PE that peered via RR. Depending solely on the edge 144 protection is dangerous, because if only one of the edge points being 145 comprised/error-configured/attacked, then all of PEs within domain 146 are under risk. 148 4) Configure the Maximum Prefix for each VRF on edge nodes 150 When a VRF overflows, PE will break down the BGP session with RR 151 according to the Maximum Prefix mechanism. However, there may have 152 several VRFs on PE rely on the PE-RR session, this mechanism will 153 influence other VRFs. 155 This draft defines a new ORF-type, called the Route Distinguisher ORF 156 (RD-ORF). Using RD-ORF mechanism, VPN routes of a VPN can be 157 controlled based on source RD and originator. This mechanism is 158 event-driven and does not need to be pre-configured. When a VRF of a 159 router overflows, the router will find out the main source address 160 and RD of VPN routes in this VRF, and send a RD-ORF to its BGP peer 161 that carrys the RD and the source address. If a BGP speaker receives 162 a RD-ORF from its BGP peer, it will filter the VPN routes it tends to 163 send according to the RD-ORF entry. 165 RD-ORF is applicable when the routers do not exchange VPN routing 166 information directly (e.g. routers in single-domain connect via Route 167 Reflector, or routers in Option B/Option AB/Option C cross-domain 168 scenario). 170 2. Conventions used in this document 172 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 173 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 174 document are to be interpreted as described in [RFC2119] . 176 3. Terminology 178 The following terms are defined in this draft: 180 o RD: Route Distinguisher, defined in [RFC4364] 182 o ORF: Outbound Route Filter, defined in [RFC5291] 183 o AFI: Address Family Identifier, defined in [RFC4760] 185 o SAFI: Subsequent Address Family Identifier, defined in [RFC4760] 187 o EVPN: BGP/MPLS Ethernet VPN, defined in [RFC7432] 189 o RR: Router Reflector, provides a simple solution to the problem of 190 IBGP full mesh connection in large-scale IBGP implementation. 192 o VRF: Virtual Routing Forwarding, a virtual routing table based on 193 VPN instance. 195 4. RD-ORF Encoding 197 In this draft, we defined a new ORF type called Route Distinguisher 198 Outbound Route Filter (RD-ORF). The ORF entries are carried in the 199 BGP ROUTE-REFRESH message as defined in [RFC5291]. A BGP ROUTE- 200 REFRESH message can carry one or more ORF entries, and MUST be 201 regenerated when it is tended to be sent to other BGP peers. The 202 ROUTE-REFRESH message which carries ORF entries contains the 203 following fields: 205 o AFI (2 octets) 207 o SAFI (1 octet) 209 o When-to-refresh (1 octet): the value is IMMEDIATE or DEFER 211 o ORF Type (1 octet) 213 o Length of ORF entries (2 octets) 215 A RD-ORF entry contains a common part and type-specific part. The 216 common part is encoded as follows: 218 o Action (2 bits): the value is ADD, REMOVE or REMOVE-ALL 220 o Match (1 bit): the value is PERMIT or DENY 222 o Reserved (5 bits) 224 RD-ORF also contains type-specific part. The encoding of the type- 225 specific part is shown in Figure 2. 227 +-----------------------------------------+ 228 | | 229 | Sequence (4 octets) | 230 | | 231 +-----------------------------------------+ 232 | | 233 | Route Distinguisher (8 octets) | 234 | | 235 +-----------------------------------------+ 236 | | 237 |Source Address sub-TLV (4,6 or 16 octets)| 238 | | 239 +-----------------------------------------+ 241 Figure 2: RD-ORF type-specific encoding 243 o Sequence: identifying the order in which RD-ORF is generated 245 o Route Distinguisher: distinguish the different user routes. The 246 RD-ORF filters the VPN routes it tends to send based on Route 247 Distinguisher. 249 o Source Address sub-TLV: the source address is TLV format, which 250 contains the following sub-TLVs: 252 * In single-domain or Option C cross-domain scenario, NEXT_HOP 253 attribute is fixed during routing transmission, so it can be 254 used as source address. 256 Type = 1, Length = 4 or 16 octets, value = NEXT_HOP. 258 * In Option B or Option AB cross-domain scenario, NEXT_HOP 259 attribute may be changed by ASBRs and cannot be used as the 260 source address. The originator can be traced by the Route 261 Origin Community in BGP (as defined in Section 5 of [RFC4360]). 263 Type = 2, Length = 6 octets, value = the value field of 264 Route Origin Community. 266 Note that if the Action component of an ORF entry specifies REMOVE- 267 ALL, the ORF entry does not include the type-specific part. 269 When the BGP ROUTE-REFRESH message carries RD-ORF entries, it must be 270 set as follows: 272 o The ORF-Type MUST be set to RD-ORF. 274 o The AFI MUST be set to IPv4, IPv6, or Layer 2 VPN (L2VPN). 276 o If the AFI is set to IPv4 or IPv6, the SAFI MUST be set to MPLS- 277 labeled VPN address. 279 o If the AFI is set to L2VPN, the SAFI MUST be set to BGP EVPN. 281 o The Match field MUST be equal to DENY. 283 5. Application in single-domain scenario 285 5.1. Addition of RD-ORF entries 287 The operation of RD-ORF mechanism on each device is independent, each 288 of them makes a local judgement to determine whether it needs to send 289 RD-ORF to its peers. 291 In general, every VRF on PE is configured a Maximum Prefix, the 292 trigger of RD-ORF mechanism can be set as the number of VPN routes in 293 VRF reach 80% of the Maximum Prefix. For RR, it doesn't have VRF and 294 the machanism can be triggered by other conditions, such as the RR's 295 memory/CPU utilization reaches 80%. 297 When the RD-ORF mechanism is triggered, the device must send an alarm 298 information to network operators. 300 5.1.1. Operation process of RD-ORF mechanism on source PE 302 In scenario shown in Figure 1, when the VRF of VPN1 in PE1 overflows, 303 PE1 will do analysis and calculation locally to find out the main 304 source of VPN routes in this VRF, assuming it is PE3. Then, PE1 will 305 resolve the host address and corresponding RD of VPN routes from BGP 306 UPDATE message, and generate a BGP ROUTE-REFRESH message contains a 307 RD-ORF entry, and send it to RR. The message contains the following 308 fields: 310 o AFI is set to IPv4 , IPv6 or L2 VPN 312 o SAFI is set to "MPLS-labeled VPN address" or "BGP EVPN" 314 o When-to-refresh is set to IMMEDIATE 316 o ORF Type is set to RD-ORF 318 o Length of ORF entries depends on the type of Source Address sub- 319 TLV (21, 23 or 33 octets) 321 o Action is set to ADD 322 o Match is set to DENY 324 o Sequence is set to 1 326 o Route Distinguisher is set to RD1 328 o Source Address sub-TLV is set to PE3's host address 330 It noted that the Sequence can uniquely identifies an RD-ORF entry. 331 All VRFs share the sequence field, and the corresponding sequence of 332 RD-ORF sent by each VRF will be recorded on the device. 334 5.1.2. Operation process of RD-ORF mechanism on RR 336 When RR receives the ROUTE-REFRESH message, it checks to find 338 whether it received the latest entry or not. If not, RR will discard 339 the entry; otherwise, RR will add the RD-ORF entry into its Adj-RIB- 340 out. 342 Before sending a VPN route toward PE1, RR will check its Adj-RIB-out 343 and find there is a filter associated with . 344 Then, RR will stop sending that VPN route to PE1. 346 If the processing capacity of RR reaches the limit (e.g. RR's 347 memory/CPU utilization reaches 80%), RR will find out the peer that 348 sends the most routing entries to it, assuming it is PE3. Then, RR 349 will generate a BGP ROUTE-REFRESH message contains a RD-ORF entry 350 based on the result of calculation, and send it to PE3. 352 5.1.3. Operation process of RD-ORF mechanism on target PE 354 After receiving the ROUTE-REFRESH message that carries a RD-ORF 355 entry, PE3 will check if it receives the latest entry. If not, PE3 356 will discard it; otherwise, PE3 will add the RD-ORF entry into its 357 Adj-RIB-out. 359 Before sending a VPN route toward RR, PE3 will check its Adj-RIB-out 360 and find the RD-ORF entry prevent it from sending VPN route which 361 carries RD1 to RR. Then, PE3 will stop sending that VPN route. 363 The BGP Maximum Prefix Features can be configured to protect PE-CE 364 peering at the edge. Therefore, in general, CEs will not cause the 365 overflow of PEs. If the boundary protection measures fail and cause 366 the overflow, the PE can calculate and find the CEs in corresponding 367 VRF, and break down the associated BGP sessions. 369 5.2. Withdraw of RD-ORF entries 371 When the RD-ORF mechanism is triggered, the alarm information will be 372 generated and sent to the network operators. Operators should 373 manually configure the network to resume normal operation. Due to 374 devices can record the RD-ORF entries sent by each VRF, operators can 375 find the entries needs to be withdrawn, and trigger the withdraw 376 process as described in [RFC5291] manually to delete them on RR/ASBR/ 377 target PE after network recovery. 379 6. Applications in cross-domain scenarios 381 6.1. Application in Option B/Option AB cross-domain scenario 383 The Option B/Option AB cross-domain scenario is shown in Figure 3: 385 +--------------------------+ +--------------------------+ 386 | | | | 387 | | | | 388 | +---------+ | | +---------+ | 389 | | PE1 | | | | PE3 | | 390 | +---------+ | | +---------+ | 391 | VPN1 \ | | / VPN1 | 392 | VPN2 \+---------+ EBGP +---------+/ VPN2 | 393 | | | | | | 394 | | ASBR1 |-----------| ASBR2 | | 395 | | | | | | 396 | +---------+ +---------+ | 397 | / | | \ | 398 | +---------+/ | | \+---------+ | 399 | | PE2 | | | | PE4 | | 400 | +---------+ | | +---------+ | 401 | VPN1 | | VPN2 | 402 | AS1 | | AS2 | 403 +--------------------------+ +--------------------------+ 405 Figure 3: The Option B/Option AB cross-domain scenario 407 In Option B cross-domain scenario, PE1 - PE4 are responsible for 408 maintaining VPN routing information in AS1 and AS2. There is a 409 direct link between ASBR1 and ASBR2 via EBGP. In AS1, PE1 and PE2 410 establish IBGP sessions with ASBR1 to ensure the routes can be 411 transmitted in AS1. In AS2, PE3 and PE4 establish IBGP session with 412 ASBR2. 414 Due to the maintenance of VPN routes is only done by PEs. ASBRs 415 cannot know whether the PEs' ability to handle VPN routes has reached 416 the upper limit or not, so it needs the RD-ORF to control the number 417 of routes. 419 Assume that PE1 - PE4 can transmit VPN routes through the network 420 architecture shown in Figure 3. When the VRF of VPN1 in PE1 421 overflows, the RD-ORF mechanism will be implemented as follows: 423 1) PE1 will check and find out the main source of VPN routes in this 424 VRF is PE3. Then, PE1 will resolve the host address and 425 corresponding RD from BGP UPDATE message, and generate a BGP ROUTE- 426 REFRESH message contains an RD-ORF entry, and send it to ASBR1. 428 2) When ASBR1 receives the ROUTE-REFRESH message, it checks whether 429 it receives the latest RD-ORF entry. If not, ASBR1 will discard the 430 entry; Otherwise, ASBR1 will add the RD-ORF entry into its Adj-RIB- 431 out. 433 Before sending a VPN route toward PE1, RR will check its Adj-RIB-out 434 and find there is a filter associated with . 435 Then, ASBR1 will stop sending that VPN route. 437 Besides, ASBR1 will locally determine if it needs to send an RD-ORF 438 entry to ASBR2. The judgment criteria refers to Section 5.1.2. 440 3) If ASBR2/PE3 receives the RD-ORF entry, it will repeat the above 441 process. 443 When the RD-ORF mechanism is triggered, network operators need to 444 manually configure the network to return to resume normal operation. 445 The withdraw of RD-ORF entries refers to Section 5.2. 447 In Option AB cross-domain scenario, ASBRs maintain VRFs. However, 448 due to VPN routes in all VRFs use the same BGP session, ASBRs cannot 449 prevent the overflow of a certain VRF by breaking down a BGP session. 450 The operation process of RD-ORF is similar to that in Option B 451 scenario. 453 6.2. Application in Option C cross-domain scenario 455 The Option C cross-domain scenario is shown in Figure 4: 457 MP-EBGP 458 +----------------------------------------+ 459 | | 460 +------------+------------+ +------------+------------+ 461 | +----+----+ | | +----+----+ | 462 | | | | | | | | 463 | +----+ RR1 +----+ | | +----+ RR2 +----+ | 464 | | | | | | | | | | | | 465 | | +---------+ | | | | +---------+ | | 466 | | | | | | | | 467 | |IBGP IBGP| | | |IBGP IBGP| | 468 | | | | | | | | 469 +-+--+----+ +----+--+-+ +-+--+----+ +----+--+-+ 470 | | | | | | | | 471 | PE1 | | ASBR1 |----------| ASBR2 | | PE2 | 472 | | | | | | | | 473 +-+-------+ AS1 +-------+-+ +-+-------+ AS2 +-------+-+ 474 +-------------------------+ +-------------------------+ 476 Figure 4: The Option C cross-domain scenario 478 In this scenario, PE1 and PE2 are responsible for maintaining VPN 479 routing information in AS1 and AS2. In order to reduce the 480 complexity that full-mesh brings to the network, RR1 and RR2 481 establish MP-EBGP session to transmit labeled routes. In AS1, PE1 482 and ASBR1 establish IBGP session with RR1 to ensure the routes can be 483 transmitted in AS1. In AS2, PE2 and ASBR2 establish IBGP session 484 with RR2. 486 Due to the maintenance of VPN routes is only done by PEs. RRs cannot 487 know whether the PEs' ability to handle VPN routes has reached the 488 upper limit or not, so it needs the RD-ORF to control the number of 489 routes. 491 The operating mechanism of RD-ORF is similar to the description in 492 Section 6.1. 494 7. Security Considerations 496 A BGP speaker will maintain the RD-ORF entries in Adj-RIB-out, this 497 behavior consumes its memory and compute resources. To avoid the 498 excessive consumption of resources, [RFC5291] specifies that a BGP 499 speaker can only accept ORF entries transmitted by its interested 500 peers. 502 8. IANA Considerations 504 This document defines a new Outbound Route Filter type - Route 505 Distinguisher Outbound Route Filter (RD-ORF). The code point is from 506 the "BGP Outbound Route Filtering (ORF) Types". It is recommended to 507 set the code point of RD-ORF to 66. 509 IANA is requested to allocate one code point for Source Address sub- 510 TLV for RD-ORF. 512 This document defines the following new RD-ORF sub-TLV types, which 513 should be reflected in the Source Address sub-TLV for RD-ORF Code 514 Point registry: 516 +----+-------------------------------------------------------------------+ 517 |Type| Description | 518 +----+-------------------------------------------------------------------+ 519 | 1 | Next hop Source Address sub-TLV | 520 +----+-------------------------------------------------------------------+ 521 | 2 | Route Origin Community Source Address sub-TLV | 522 +----+-------------------------------------------------------------------+ 524 9. Acknowledgement 526 Thanks Robert Raszuk, Jim Uttaro, Jakob Heitz, Jeff Tantsura, Rajiv 527 Asati, John E Drake and Gert Doering for their valuable comments on 528 this draft. 530 10. Normative References 532 [I-D.ietf-bess-evpn-inter-subnet-forwarding] 533 Sajassi, A., Salam, S., Thoria, S., Drake, J., and J. 534 Rabadan, "Integrated Routing and Bridging in EVPN", draft- 535 ietf-bess-evpn-inter-subnet-forwarding-09 (work in 536 progress), June 2020. 538 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 539 Requirement Levels", BCP 14, RFC 2119, 540 DOI 10.17487/RFC2119, March 1997, 541 . 543 [RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended 544 Communities Attribute", RFC 4360, DOI 10.17487/RFC4360, 545 February 2006, . 547 [RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private 548 Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February 549 2006, . 551 [RFC4684] Marques, P., Bonica, R., Fang, L., Martini, L., Raszuk, 552 R., Patel, K., and J. Guichard, "Constrained Route 553 Distribution for Border Gateway Protocol/MultiProtocol 554 Label Switching (BGP/MPLS) Internet Protocol (IP) Virtual 555 Private Networks (VPNs)", RFC 4684, DOI 10.17487/RFC4684, 556 November 2006, . 558 [RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter, 559 "Multiprotocol Extensions for BGP-4", RFC 4760, 560 DOI 10.17487/RFC4760, January 2007, 561 . 563 [RFC5291] Chen, E. and Y. Rekhter, "Outbound Route Filtering 564 Capability for BGP-4", RFC 5291, DOI 10.17487/RFC5291, 565 August 2008, . 567 [RFC5292] Chen, E. and S. Sangli, "Address-Prefix-Based Outbound 568 Route Filter for BGP-4", RFC 5292, DOI 10.17487/RFC5292, 569 August 2008, . 571 [RFC7432] Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A., 572 Uttaro, J., Drake, J., and W. Henderickx, "BGP MPLS-Based 573 Ethernet VPN", RFC 7432, DOI 10.17487/RFC7432, February 574 2015, . 576 Authors' Addresses 578 Wei Wang 579 China Telecom 580 Beiqijia Town, Changping District 581 Beijing, Beijing 102209 582 China 584 Email: wangw36@chinatelecom.cn 586 Aijun Wang 587 China Telecom 588 Beiqijia Town, Changping District 589 Beijing, Beijing 102209 590 China 592 Email: wangaj3@chinatelecom.cn 593 Haibo Wang 594 Huawei Technologies 595 Huawei Building, No.156 Beiqing Rd. 596 Beijing, Beijing 100095 597 China 599 Email: rainsword.wang@huawei.com 601 Gyan S. Mishra 602 Verizon Inc. 603 13101 Columbia Pike 604 Silver Spring MD 20904 605 United States of America 607 Phone: 301 502-1347 608 Email: gyan.s.mishra@verizon.com 610 Shunwan Zhuang 611 Huawei Technologies 612 Huawei Building, No.156 Beiqing Rd. 613 Beijing, Beijing 100095 614 China 616 Email: zhuangshunwan@huawei.com 618 Jie Dong 619 Huawei Technologies 620 Huawei Building, No.156 Beiqing Rd. 621 Beijing, Beijing 100095 622 China 624 Email: jie.dong@huawei.com