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So 11 Reliance Jio 12 February 16, 2020 14 The IPv6 Compressed Routing Header (CRH) 15 draft-bonica-6man-comp-rtg-hdr-11 17 Abstract 19 This document defines two new Routing header types. Collectively, 20 they are called the Compressed Routing Headers (CRH). Individually, 21 they are called CRH-16 and CRH-32. 23 Status of This Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at https://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on August 19, 2020. 40 Copyright Notice 42 Copyright (c) 2020 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (https://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. Code Components extracted from this document must 51 include Simplified BSD License text as described in Section 4.e of 52 the Trust Legal Provisions and are provided without warranty as 53 described in the Simplified BSD License. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 58 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 59 3. The Compressed Routing Headers (CRH) . . . . . . . . . . . . 3 60 4. The CRH Forwarding Information Base (CRH-FIB) . . . . . . . 5 61 5. Processing Rules . . . . . . . . . . . . . . . . . . . . . . 5 62 5.1. Computing Minimum CRH Length . . . . . . . . . . . . . . 7 63 6. Mutability . . . . . . . . . . . . . . . . . . . . . . . . . 8 64 7. Applications And SIDs . . . . . . . . . . . . . . . . . . . . 8 65 8. Management Considerations . . . . . . . . . . . . . . . . . . 8 66 9. ICMPv6 Considerations . . . . . . . . . . . . . . . . . . . . 8 67 10. Security Considerations . . . . . . . . . . . . . . . . . . . 8 68 11. Implementation and Deployment Status . . . . . . . . . . . . 9 69 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 70 13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 71 14. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 9 72 15. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 73 15.1. Normative References . . . . . . . . . . . . . . . . . . 11 74 15.2. Informative References . . . . . . . . . . . . . . . . . 11 75 Appendix A. CRH Processing Examples . . . . . . . . . . . . . . 12 76 Appendix B. CRH Processing Examples . . . . . . . . . . . . . . 13 77 B.1. The SID List Contains One Entry For Each Segment In The 78 Path . . . . . . . . . . . . . . . . . . . . . . . . . . 14 79 B.2. The SID List Omits The First Entry In The Path . . . . . 15 80 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 82 1. Introduction 84 IPv6 [RFC8200] source nodes use Routing headers to specify the path 85 that a packet takes to its destination. The IETF has defined several 86 Routing header types [IANA-RH]. RH0 [RFC5095] was the first to be 87 defined and was deprecated because of security vulnerabilities. 89 This document defines two new Routing header types. Collectively, 90 they are called the Compressed Routing Headers (CRH). Individually, 91 they are called CRH-16 and CRH-32. 93 The CRH, like RH0, allows IPv6 source nodes to specify the path that 94 a packet takes to its destination. The CRH differs from RH0 because: 96 o It can be encoded in fewer bytes than RH0. 98 o It addresses the security vulnerabilities that affected RH0. 100 The following are reasons for encoding the CRH in as few bytes as 101 possible: 103 o Many ASIC-based forwarders copy all headers from buffer memory to 104 on-chip memory. As header sizes increase, so does the cost of 105 this copy. 107 o Because Path MTU Discovery (PMTUD) [RFC8201] is not entirely 108 reliable, many IPv6 hosts refrain from sending packets larger than 109 the IPv6 minimum link MTU (i.e., 1280 bytes). When packets are 110 small, the overhead imposed by large Routing Headers is excessive. 112 Section 10 of this document addresses security considerations. 113 Appendix A of this document demonstrates how the CRH can be encoded 114 in fewer bytes than RH0. 116 2. Requirements Language 118 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 119 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 120 "OPTIONAL" in this document are to be interpreted as described in BCP 121 14 [RFC2119] [RFC8174] when, and only when, they appear in all 122 capitals, as shown here. 124 3. The Compressed Routing Headers (CRH) 126 Both CRH versions (i.e., CRH-16 and CRH-32) contain the following 127 fields: 129 o Next Header - Defined in [RFC8200]. 131 o Hdr Ext Len - Defined in [RFC8200]. 133 o Routing Type - Defined in [RFC8200]. Value TBD by IANA. (For 134 CRH-16, the suggested value is 5. For CRH-32, the suggested value 135 is 6.) 137 o Segments Left - Defined in [RFC8200]. 139 o Type-specific Data - Described in [RFC8200]. 141 In the CRH, the Type-specific data field contains a list of Segment 142 Identifiers (SIDs). Each SID represents both of the following: 144 o A segment of the path that the packet takes to its destination. 146 o An entry in the CRH Forwarding Information Base (CRH-FIB) 147 (Section 4). 149 SIDs are listed in reverse order. So, the first SID in the list 150 represents the final segment in the path. Because segments are 151 listed in reverse order, the Segments Left field can be used as an 152 index into the SID list. In this document, the "current SID" is the 153 SID list entry referenced by the Segments Left field. 155 The first segment in the path can be omitted from the list. See 156 (Appendix B) for examples. 158 In the CRH-16 (Figure 1), each SID is encoded in 16-bits. In the 159 CRH-32 (Figure 2), each SID is encoded in 32-bits. 161 In all cases, the CRH MUST end on a 64-bit boundary. So, the Type- 162 specific data field MAY be padded with zeros. 164 0 1 2 3 165 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 1 166 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 167 | Next Header | Hdr Ext Len | Routing Type | Segments Left | 168 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 169 | SID[0] | SID[1] | 170 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| 171 | ......... 172 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 174 Figure 1: CRH-16 176 0 1 2 3 177 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 1 178 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 179 | Next Header | Hdr Ext Len | Routing Type | Segments Left | 180 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 181 + SID[0] + 182 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 183 + SID[1] + 184 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 185 // // 186 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 187 + SID[n] + 188 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 190 Figure 2: CRH-32 192 4. The CRH Forwarding Information Base (CRH-FIB) 194 Each SID identifies a CRH-FIB entry. 196 Each CRH-FIB entry contains: 198 o A IPv6 address. 200 o A forwarding method. 202 o Method-specific parameters (optional). 204 The IPv6 address represents an interface on the next segment 205 endpoint. It MUST NOT be a link-local address. While the IPv6 206 address represents an interface on the next segment endpoint, it does 207 not necessarily represent the interface through which the packet will 208 arrive at the next segment endpoint. 210 The forwarding method specifies how the processing node will forward 211 the packet to the next segment endpoint. The following are examples: 213 o Forward the packet to the next-hop along the least-cost path to 214 the next segment endpoint. 216 o Forward the packet through a specified interface to the next 217 segment endpoint. 219 Some forwarding methods require method-specific parameters. For 220 example, a forwarding method might require a parameter that 221 identifies the interface through which the packet should be 222 forwarded. 224 The CRH-FIB can be populated: 226 o By an operator, using a Command Line Interface (CLI). 228 o By a controller, using the Path Computation Element (PCE) 229 Communication Protocol (PCEP) [RFC5440] or the Network 230 Configuration Protocol (NETCONF) [RFC6241]. 232 o By a distributed routing protocol [ISO10589-Second-Edition], 233 [RFC5340], [RFC4271]. 235 5. Processing Rules 237 The following rules apply to packets that contain a CRH: 239 o If the IPv6 Source Address is a link-local address, discard the 240 packet. 242 o If the IPv6 Source Address is a multicast address, discard the 243 packet. 245 o If the IPv6 Destination Address is a link-local address, discard 246 the packet. 248 o If the IPv6 Hop Limit is less than or equal to 1, discard the 249 packet and send an ICMPv6 Time Exceeded message to the Source 250 Address. 252 The following rules describe CRH processing: 254 o If Segments Left equals 0, skip over the CRH and process the next 255 header in the packet. 257 o If Hdr Ext Len indicates that the CRH is larger than the 258 implementation can process, discard the packet and send an ICMPv6 259 Parameter Problem, Code 0, message to the Source Address, pointing 260 to the Hdr Ext Len field. 262 o Compute L, the minimum CRH length (See (Section 5.1)). 264 o If L is greater than Hdr Ext Len, discard the packet and send an 265 ICMPv6 Parameter Problem, Code 0, message to the Source Address, 266 pointing to the Segments Left field. 268 o Decrement Segments Left. 270 o Search for the current SID in the CRH-FIB. In this document, the 271 "current SID" is the SID list entry referenced by the Segments 272 Left field. 274 o If the search does not return a CRH-FIB entry, discard the packet 275 and send an ICMPv6 Parameter Problem, Code 0, message to the 276 Source Address, pointing to the current SID. 278 o If the CRH-FIB entry contains a link-local address, discard the 279 packet and send an ICMPv6 Parameter Problem, Code 0, message to 280 the Source Address, pointing to the current SID. 282 o If Segments Left is greater than 0 and the CRH-FIB entry contains 283 a multicast address, discard the packet and send an ICMPv6 284 Parameter Problem, Code 0, message to the Source Address, pointing 285 to the current SID. 287 o Copy the IPv6 address from the CRH-FIB entry to the Destination 288 Address field in the IPv6 header. 290 o Decrement the IPv6 Hop Limit. 292 o Resubmit the packet to the IPv6 module for transmission to the new 293 destination, ensuring that it executes the forwarding method 294 specified by the CRH-FIB entry. 296 5.1. Computing Minimum CRH Length 298 The algorithm described in this section accepts the following CRH 299 fields as its input parameters: 301 o Routing Type (i.e., CRH-16 or CRH-32). 303 o Segments Left. 305 It yields L, the minimum CRH length. The minimum CRH length is 306 measured in 8-octet units, not including the first 8 octets. 308 310 switch(Routing Type) { 311 case CRH-16: 312 if (Segments Left <= 2) 313 return(0) 314 sidsBeyondFirstWord = Segments Left - 2; 315 sidPerWord = 4; 316 case CRH-32: 317 if (Segments Left <= 1) 318 return(0) 319 sidsBeyondFirstWord = Segments Left - 1; 320 sidsPerWord = 2; 321 case default: 322 return(0xFF); 323 } 325 words = sidsBeyondFirstWord div sidsPerWord; 326 if (sidsBeyondFirstWord mod sidsPerWord) 327 words++; 329 return(words) 331 333 6. Mutability 335 In the CRH, the Segments Left field is mutable. All remaining fields 336 are immutable. 338 7. Applications And SIDs 340 A CRH contains one or more SIDs. Each SID is processed by exactly 341 one node. 343 Therefore, a SID is not required to have domain-wide significance. 344 Applications can: 346 o Allocate SIDs so that they have domain-wide significance. 348 o Allocate SIDs so that they have node-local significance. 350 8. Management Considerations 352 PING and TRACEROUTE [RFC2151] both operate correctly in the presence 353 of the CRH. 355 9. ICMPv6 Considerations 357 Implementations MUST comply with the ICMPv6 processing rules 358 specified in Section 2.4 of [RFC4443]. For example: 360 o An implementation MUST NOT originate an ICMPv6 error message in 361 response to another ICMPv6 error message. 363 o An implementation MUST rate limit the ICMPv6 messages that it 364 originates. 366 10. Security Considerations 368 Networks that process the CRH MUST mitigate the security 369 vulnerabilities described in [RFC5095]. Their border routers SHOULD 370 discard packets that satisfy the following criteria: 372 o The packet contains a CRH 374 o The Segments Left field in the CRH has a value greater than 0 376 o The Destination Address field in the IPv6 header represents an 377 interface that resides inside of the network. 379 Many border routers cannot filter packets based upon the Segments 380 Left value. These border routers MAY discard packets that satisfy 381 the following criteria: 383 o The packet contains a CRH 385 o The Destination Address field in the IPv6 header represents an 386 interface that resides inside of the network. 388 11. Implementation and Deployment Status 390 Juniper Networks has produced experimental implementations of the CRH 391 on: 393 o A LINUX-based software platform 395 o The MX-series (ASIC-based) router 397 Liquid Telecom has deployed the CRH, on a limited basis, in their 398 network. Other experimental deployments are in progress. 400 12. IANA Considerations 402 IANA is requested to make the following entries in the Internet 403 Protocol Version 6 (IPv6) Parameters "Routing Type" registry 404 [IANA-RH]: 406 Suggested 407 Value Description Reference 408 --------------------------------------------------------------------- 409 5 Compressed Routing Header (16-bit) (CRH-16) This document 410 6 Compressed Routing Header (32-bit) (CRH-32) This document 412 13. Acknowledgements 414 Thanks to Dr. Vanessa Ameen, Naveen Kottapalli, Joel Halpern, Tony 415 Li, Gerald Schmidt, Nancy Shaw, and Chandra Venkatraman for their 416 contributions to this document. 418 14. Contributors 420 Luay Jalil 422 Verizon 424 Richardson, Texas USA 426 Email: luay.jalil@one.verizon.com 427 Fengman Xu 429 Reliance Jio 431 3010 Gaylord PKWY, Suite 150 433 Frisco, Texas 75034 435 USA 437 Email: Fengman.Xu@ril.com 439 Daniam Henriques 441 Liquid Telecom 443 Johannesburg, South Africa 445 Email: daniam.henriques@liquidtelecom.com 447 Gang Chen 449 Baidu 451 No.10 Xibeiwang East Road Haidian District 453 Beijing 100193 P.R. China 455 Email: phdgang@gmail.com 457 Yifeng Zhou 459 ByteDance 461 Building 1, AVIC Plaza, 43 N 3rd Ring W Rd Haidian District 463 Beijing 100000 P.R. China 465 Email: yifeng.zhou@bytedance.com 467 15. References 469 15.1. Normative References 471 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 472 Requirement Levels", BCP 14, RFC 2119, 473 DOI 10.17487/RFC2119, March 1997, 474 . 476 [RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet 477 Control Message Protocol (ICMPv6) for the Internet 478 Protocol Version 6 (IPv6) Specification", STD 89, 479 RFC 4443, DOI 10.17487/RFC4443, March 2006, 480 . 482 [RFC5095] Abley, J., Savola, P., and G. Neville-Neil, "Deprecation 483 of Type 0 Routing Headers in IPv6", RFC 5095, 484 DOI 10.17487/RFC5095, December 2007, 485 . 487 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 488 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 489 May 2017, . 491 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 492 (IPv6) Specification", STD 86, RFC 8200, 493 DOI 10.17487/RFC8200, July 2017, 494 . 496 [RFC8201] McCann, J., Deering, S., Mogul, J., and R. Hinden, Ed., 497 "Path MTU Discovery for IP version 6", STD 87, RFC 8201, 498 DOI 10.17487/RFC8201, July 2017, 499 . 501 15.2. Informative References 503 [IANA-RH] IANA, "Routing Headers", 504 . 507 [ISO10589-Second-Edition] 508 International Organization for Standardization, 509 ""Intermediate system to Intermediate system intra-domain 510 routeing information exchange protocol for use in 511 conjunction with the protocol for providing the 512 connectionless-mode Network Service (ISO 8473)", ISO/IEC 513 10589:2002, Second Edition,", November 2001. 515 [RFC2151] Kessler, G. and S. Shepard, "A Primer On Internet and TCP/ 516 IP Tools and Utilities", FYI 30, RFC 2151, 517 DOI 10.17487/RFC2151, June 1997, 518 . 520 [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A 521 Border Gateway Protocol 4 (BGP-4)", RFC 4271, 522 DOI 10.17487/RFC4271, January 2006, 523 . 525 [RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF 526 for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008, 527 . 529 [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation 530 Element (PCE) Communication Protocol (PCEP)", RFC 5440, 531 DOI 10.17487/RFC5440, March 2009, 532 . 534 [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., 535 and A. Bierman, Ed., "Network Configuration Protocol 536 (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, 537 . 539 Appendix A. CRH Processing Examples 541 The CRH-16 and CRH-32 encode information more efficiently than RH0. 543 +------+-----+--------+--------+ 544 | SIDs | RH0 | CRH-16 | CRH-32 | 545 +------+-----+--------+--------+ 546 | 1 | 24 | 8 | 8 | 547 | 2 | 40 | 8 | 16 | 548 | 3 | 56 | 16 | 16 | 549 | 4 | 72 | 16 | 24 | 550 | 5 | 88 | 16 | 24 | 551 | 6 | 104 | 16 | 32 | 552 | 7 | 120 | 24 | 32 | 553 | 8 | 136 | 24 | 40 | 554 | 9 | 152 | 24 | 40 | 555 | 10 | 168 | 24 | 48 | 556 | 11 | 184 | 32 | 48 | 557 | 12 | 200 | 32 | 52 | 558 | 13 | 216 | 32 | 52 | 559 | 14 | 232 | 32 | 56 | 560 | 15 | 248 | 40 | 56 | 561 | 16 | 264 | 40 | 60 | 562 | 17 | 280 | 40 | 60 | 563 | 18 | 296 | 40 | 64 | 564 +------+-----+--------+--------+ 566 Table 1: Routing Header Size (in Bytes) As A Function Of Routing 567 Header Type and Number Of SIDs 569 (Table 1) reflects Routing header size as a function of Routing 570 header type and number of SIDs contained by the Routing header. 572 Appendix B. CRH Processing Examples 574 This appendix demonstrates CRH processing in the following scenarios: 576 o The SID list contains one entry for each segment in the path 577 (Appendix B.1). 579 o The SID list omits the first entry in the path (Appendix B.2). 581 ----------- ----------- ----------- 582 |Node: S | |Node: I1 | |Node: I2 | 583 |Loopback: |---------------|Loopback: |---------------|Loopback: | 584 |2001:db8::a| |2001:db8::1| |2001:db8::2| 585 ----------- ----------- ----------- 586 | | 587 | ----------- | 588 | |Node: D | | 589 ---------------------|Loopback: |--------------------- 590 |2001:db8::b| 591 ----------- 593 Figure 3: Reference Topology 595 Figure 3 provides a reference topology that is used in all examples. 597 +-----+--------------+-------------------+ 598 | SID | IPv6 Address | Forwarding Method | 599 +-----+--------------+-------------------+ 600 | 2 | 2001:db8::2 | Least-cost path | 601 | 11 | 2001:db8::b | Least-cost path | 602 +-----+--------------+-------------------+ 604 Table 2: Node SIDs 606 Table 2 describes two entries that appear in each node's CRH-FIB. 608 B.1. The SID List Contains One Entry For Each Segment In The Path 610 In this example, Node S sends a packet to Node D, via I2. In this 611 example, I2 appears in the CRH segment list. 613 +-------------------------------------+-------------------+ 614 | As the packet travels from S to I2: | | 615 +-------------------------------------+-------------------+ 616 | Source Address = 2001:db8::a | Segments Left = 1 | 617 | Destination Address = 2001:db8::2 | SID[0] = 11 | 618 | | SID[1] = 2 | 619 +-------------------------------------+-------------------+ 621 +-------------------------------------+-------------------+ 622 | As the packet travels from I2 to D: | | 623 +-------------------------------------+-------------------+ 624 | Source Address = 2001:db8::a | Segments Left = 0 | 625 | Destination Address = 2001:db8::b | SID[0] = 11 | 626 | | SID[1] = 2 | 627 +-------------------------------------+-------------------+ 629 B.2. The SID List Omits The First Entry In The Path 631 In this example, Node S sends a packet to Node D, via I2. In this 632 example, I2 does not appear in the CRH segment list. 634 +-------------------------------------+-------------------+ 635 | As the packet travels from S to I2: | | 636 +-------------------------------------+-------------------+ 637 | Source Address = 2001:db8::a | Segments Left = 1 | 638 | Destination Address = 2001:db8::2 | SID[0] = 11 | 639 +-------------------------------------+-------------------+ 641 +-------------------------------------+-------------------+ 642 | As the packet travels from I2 to D: | | 643 +-------------------------------------+-------------------+ 644 | Source Address = 2001:db8::a | Segments Left = 0 | 645 | Destination Address = 2001:db8::b | SID[0] = 11 | 646 +-------------------------------------+-------------------+ 648 Authors' Addresses 650 Ron Bonica 651 Juniper Networks 652 2251 Corporate Park Drive 653 Herndon, Virginia 20171 654 USA 656 Email: rbonica@juniper.net 658 Yuji Kamite 659 NTT Communications Corporation 660 3-4-1 Shibaura, Minato-ku 661 Tokyo 108-8118 662 Japan 664 Email: y.kamite@ntt.com 666 Tomonobu Niwa 667 KDDI 668 3-22-7, Yoyogi, Shibuya-ku 669 Tokyo 151-0053 670 Japan 672 Email: to-niwa@kddi.com 673 Andrew Alston 674 Liquid Telecom 675 Nairobi 676 Kenya 678 Email: Andrew.Alston@liquidtelecom.com 680 Ning So 681 Reliance Jio 682 3010 Gaylord PKWY, Suite 150 683 Frisco, Texas 75034 684 USA 686 Email: Ning.So@ril.com