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Please use uppercase 'NOT' together with RFC 2119 keywords (if that is what you mean). Found 'MUST not' in this paragraph: o The MPLS Label field in the BIER PTA of the BGP-MVPN x-PMSI A-D route MUST be ignored and MUST not be used for the identification of the VRF. -- The document date (October 10, 2020) is 1293 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Missing Reference: 'RFC8114' is mentioned on line 314, but not defined == Outdated reference: A later version (-15) exists of draft-ietf-bess-srv6-services-04 == Outdated reference: A later version (-28) exists of draft-ietf-spring-srv6-network-programming-24 == Outdated reference: A later version (-10) exists of draft-xie-bier-ipv6-encapsulation-08 Summary: 0 errors (**), 0 flaws (~~), 6 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group J. Xie 3 Internet-Draft Huawei Technologies 4 Intended status: Standards Track M. McBride 5 Expires: April 13, 2021 Futurewei 6 S. Dhanaraj 7 Huawei Technologies 8 L. Geng 9 China Mobile 10 G. Mishra 11 Verizon Inc. 12 October 10, 2020 14 Use of BIER IPv6 Encapsulation (BIERv6) for Multicast VPN in IPv6 15 networks 16 draft-xie-bier-ipv6-mvpn-03 18 Abstract 20 This draft defines the procedures and messages for using Bit Index 21 Explicit Replication (BIER) for Multicast VPN Services in IPv6 22 networks using the BIER IPv6 encapsulation. It provides a migration 23 path for Multicast VPN service using BIER MPLS encapsulation in MPLS 24 networks to multicast VPN service using BIER IPv6 encapsulation 25 (BIERv6) in IPv6 networks. 27 Requirements Language 29 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 30 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 31 document are to be interpreted as described in [RFC2119] and 32 [RFC8174]. 34 Status of This Memo 36 This Internet-Draft is submitted in full conformance with the 37 provisions of BCP 78 and BCP 79. 39 Internet-Drafts are working documents of the Internet Engineering 40 Task Force (IETF). Note that other groups may also distribute 41 working documents as Internet-Drafts. The list of current Internet- 42 Drafts is at https://datatracker.ietf.org/drafts/current/. 44 Internet-Drafts are draft documents valid for a maximum of six months 45 and may be updated, replaced, or obsoleted by other documents at any 46 time. It is inappropriate to use Internet-Drafts as reference 47 material or to cite them other than as "work in progress." 48 This Internet-Draft will expire on April 13, 2021. 50 Copyright Notice 52 Copyright (c) 2020 IETF Trust and the persons identified as the 53 document authors. All rights reserved. 55 This document is subject to BCP 78 and the IETF Trust's Legal 56 Provisions Relating to IETF Documents 57 (https://trustee.ietf.org/license-info) in effect on the date of 58 publication of this document. Please review these documents 59 carefully, as they describe your rights and restrictions with respect 60 to this document. Code Components extracted from this document must 61 include Simplified BSD License text as described in Section 4.e of 62 the Trust Legal Provisions and are provided without warranty as 63 described in the Simplified BSD License. 65 Table of Contents 67 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 68 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 69 3. Use of PTA and Prefix-SID Attribute in x-PMSI A-D Routes . . 4 70 4. MVPN over BIERv6 Core . . . . . . . . . . . . . . . . . . . . 4 71 5. GTM over BIERv6 Core . . . . . . . . . . . . . . . . . . . . 6 72 6. Data Plane . . . . . . . . . . . . . . . . . . . . . . . . . 7 73 6.1. Encapsulation of Multicast Traffic . . . . . . . . . . . 7 74 6.2. MTU . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 75 6.3. TTL . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 76 7. Security Considerations . . . . . . . . . . . . . . . . . . . 9 77 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 78 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 79 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 80 10.1. Normative References . . . . . . . . . . . . . . . . . . 9 81 10.2. Informative References . . . . . . . . . . . . . . . . . 11 82 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 84 1. Introduction 86 Bit Index Explicit Replication (BIER) [RFC8279] is an architecture 87 that provides optimal multicast forwarding without requiring 88 intermediate routers to maintain any per-flow state by using a 89 multicast-specific BIER header. BIERv6 refers to the deployment of 90 BIER in IPv6 networks using the BIER IPv6 encapsulation format 91 defined in [I-D.xie-bier-ipv6-encapsulation]. 93 This document describes a method to realize MVPN services using BIER 94 as a P-tunnel in the IPv6 Networks (BIERv6 Networks). It defines a 95 method to use an IPv6 address, called Src.DTx in this document, as 96 source address of an IPv6 header, to identify the MVPN instance at 97 the Egress PE. The Src.DTx address used as source address of a 98 BIERv6 packet represent both the context and the upstream-assigned 99 VPN Label in MVPN scenario defined in [RFC8556]. 101 The Src.DTx address can be a normal IPv6 address of the BFR, for 102 example, a loopback address of the BFR. The Src.DTx address can also 103 be an IPv6 address allocated from an IPv6 address block, for example, 104 an IPv6 address allocated from an SRv6 locator if BIERv6 MVPN is 105 deployed in an SRv6 network. 107 In particular, MVPN deployment in IPv6 networks relies on L3VPN 108 deployment on IPv6 networks firstly, thus the c-multicast routing 109 procedure like Upstream Multicast Hop (UMH) Selection can be done. 110 As an example, the L3VPN deployment in SRv6 networks can be referred 111 to [I-D.ietf-bess-srv6-services]. 113 Global Table Multicast (GTM) defined in [RFC7716] is also covered in 114 this document, as GTM shares the same BGP-MVPN signalling, while 115 providing an approach of Non-VPN multicast over a service provider 116 core with various P-tunnel type. For the same reason of UMH 117 selection as a base of GTM, the Global IPv4/IPv6 over SRv6 networks 118 can be referred to [I-D.ietf-bess-srv6-services]. 120 2. Terminology 122 Readers of this document are assumed to be familiar with the 123 terminology and concepts of the documents listed as Normative 124 References. Additionally the following terms are used through out 125 the document. 127 o BIERv6 - BIER in IPv6 networks using the BIERv6 encapsulation 128 format defined in [I-D.xie-bier-ipv6-encapsulation]. 130 o SRv6 - Segment Routing instantiated on the IPv6 dataplane as 131 defined in [I-D.ietf-spring-srv6-network-programming]. 133 o SRv6 SID - SRv6 Segment Identifier as defined in 134 [I-D.ietf-spring-srv6-network-programming]. 136 o End.DTx - Refers to the functions End.DT6, End.DT4, End.DT46 137 defined in [I-D.ietf-spring-srv6-network-programming]. 139 o Src.DTx - Refers to the functions Src.DT4, Src.DT6, Src.DT46 140 defind in this document. 142 o SRv6 L3 Service - L3VPN/Global-L3 service in SRv6 networks defined 143 in [I-D.ietf-bess-srv6-services], or MVPN/GTM service in BIERv6 144 networks defined in this document. 146 3. Use of PTA and Prefix-SID Attribute in x-PMSI A-D Routes 148 The BGP-MVPN I-PMSI A-D (Type 1) or S-PMSI A-D (Type 3) route (called 149 x-PMSI A-D route in this document), advertised by Ingress PE carries 150 the BIER (Type 11) PTA as specified in [RFC8556]. The BIER PTA 151 carried in the x-PMSI A-D route is used for explicitly tracking the 152 receiver-site PEs which are interested in a specific multicast flow. 153 It includes three BIER-specific fields, Sub-domain-id, BFR-id, and 154 BFR-prefix. For BIER P-tunnel using the BIERv6 encapsulation in IPv6 155 networks, the BFR-prefix field in the PTA MUST be set to the BFIR 156 IPv6 prefix and the MPLS Label field in the PTA MUST set to 0. For 157 MVPN over BIERv6, the Src.DTx IPv6 address of the BFIR is used to 158 identify the VRF instead of an MPLS Label. The Src.DTx IPv6 Address 159 (Src.DT6 or Src.DT4 or Src.DT46) MUST be carried within an SRv6 L3 160 Service TLV [I-D.ietf-bess-srv6-services] of BGP Prefix-SID attribute 161 in the x-PMSI A-D route. 163 The Ingress PE encapsulates the c-multicast IP packet with BIERv6 164 header and the source address in the outer IPv6 header will be set to 165 the Src.DTx IPv6 address advertised in the BGP-MVPN x-PMSI A-D 166 routes. See section 3 of [I-D.xie-bier-ipv6-encapsulation] for the 167 detailed packet format. 169 Egress PE (BFER) receiving the x-PMSI A-D routes with BIER PTA and 170 SRv6 L3 Service TLV learns the Src.DTx IPv6 address and uses it to 171 identify the VRF of the c-multicast packet. 173 When Egress PE receives a BIERv6 packet and the self bfr-id is set in 174 the bit-string field of the BIERv6 header, it retrieves the Src.DTx 175 IPv6 address from the source address of the IPv6 header to determine 176 the VRF and the Address Family (AF) of the c-multicast data packet, 177 and performs the MFIB lookup in the corresponding table. 179 4. MVPN over BIERv6 Core 181 [RFC8556] specifies the protocol and procedures to be followed by the 182 Ingress and Egress PEs to use BIER as a P-tunnel for MVPN in MPLS 183 networks. This section specifies the required changes and procedures 184 in addition to support BIER as a P-tunnel in IPv6 networks using 185 BIERv6. 187 In a IPv6 service provider network, many of the IP address fields 188 used in the BGP-MVPN routes are IPv6 address as specified in 189 [RFC6515]. These are listed below. 191 o "Originating Router's IP Address" in the NLRI of Type 1, 3 or 4 192 BGP-MVPN route is an IPv6 address. 194 o "Network Address of Next Hop" field in the MP_REACH_NLRI attribute 195 is an IPv6 address. 197 o Route Targets Extended Community (EC) used in C-multicast join 198 (Type 6 or 7) route or Leaf A-D (Type 4) route is an IPv6 Address 199 Specific Extended Community, where the Global Administrator field 200 will be an IPv6 address identifies the Upstream PE or the UMH. 202 o "VRF Route Import Extended Community (EC)" carried by VPNv4 or 203 VPNv6 unicast routes (SAFI 128) or multicast routes (SAFI 129) is 204 an IPv6 Address Specific Extended Community. 206 On the Ingress PE (BFIR), the BGP-MVPN x-PMSI A-D route is 207 constructed as per the procedures specified in [RFC8556] and with the 208 following specifications. 210 o MPLS Label field in the BIER PTA MUST be set to Zero. 212 o BFR-prefix field in the BIER PTA MUST be set to the Ingress PEs 213 (BFIR) IPv6 BFR-Prefix Address. It does not need to be the same 214 as the other IPv6 address of the x-PMSI AD route. 216 o Route MUST also carry an BGP Prefix SID attribute with an SRv6 L3 217 Service TLV carrying an Src.DTx IPv6 address uniquely identifying 218 the MVPN instance. 220 If the MVPN is IPv4 MVPN, the Src.DTx can be either Src.DT4 or 221 Src.DT46. If the MVPN is IPv6 MVPN, the Src.DTx can be either 222 Src.DT6 or Src.DT46. The distribution of the x-PMSI A-D routes uses 223 the Src.DTx according to the local configuration, and is independent 224 to the use of End.DTx in VPN-IP unicast routes of this VPN. For 225 example, one can use End.DT46 for VPNv4 and VPNv6 unicast routes, but 226 use Src.DT4 for the MVPN routes for the same VPN. Another example, 227 one can use End.DX for VPNv4 unicast routes, but use Src.DT46 for the 228 MVPN routes for the same VPN. 230 BFIR MAY carry the BGP Prefix-SID attribute only in I-PMSI A-D route 231 when I-PMSI A-D route is used, while other S-PMSI A-D routes do not 232 carry the BGP Prefix-SID attribute. 234 BFIR MAY carry the BGP Prefix-SID attribute only in wildcard S-PMSI 235 A-D routes when the "S-PMSI Only" mode as described in [RFC6625] is 236 used, while other S-PMSI A-D routes do not carry the BGP Prefix-SID 237 attribute. 239 On the Egress PE (BFER), the BGP-MVPN x-PMSI A-D route is processed 240 as per the procedures specified in [RFC8556] and with the following 241 specifications: 243 o The MPLS Label field in the BIER PTA of the BGP-MVPN x-PMSI A-D 244 route MUST be ignored and MUST not be used for the identification 245 of the VRF. 247 o The BGP-MVPN x-PMSI A-D route MUST be dropped if the BFR-prefix 248 field in the BIER PTA is not an IPv6 address. 250 o The BGP-MVPN x-PMSI A-D route MUST be dropped if it does not carry 251 a Src.DTx IPv6 address in the SRv6 L3 Service TLV in BGP Prefix 252 SID attribute. 254 o Leaf A-D route originated by the Egress PE (BFER) MUST carry the 255 BIER PTA with the BFR-prefix field set to the BFER IPv6 BFR- 256 prefix. 258 Valid BGP-MVPN x-PMSI A-D route received by an Egress PE (BFER) is 259 stored locally, and the Src.DTx IPv6 Address carried in the SRv6 L3 260 service TLV is used to identify the VRF of a c-multicast data packet. 261 This may be populated into forwarding table only when there is 262 c-multicast flow state with UMH of the specific BFIR this Src.DTx 263 located in. 265 If more than one x-PMSI A-D routes belonging to the same VRF has 266 different Src.DTx value, the processing is determined by the local 267 policy of the BFER. 269 If more than one x-PMSI A-D routes belonging to different VRF has the 270 same Src.DTx value, the BFER must log an error, and a BIERv6 packet 271 with this Src.DTx as the IPv6 source address MUST be dropped. 273 The BGP Prefix-SID attribute (which may include the Src.DTx in SRv6 274 L3 Service TLV) MUST NOT be carried in Leaf A-D route upon sending, 275 and MUST be ignored upon reception. 277 5. GTM over BIERv6 Core 279 As specified in [RFC7716], Global Table Multicast (GTM) uses the same 280 Subsequent Address Family Identifier (SAFI) value, the same Network 281 Layer Reachability Information (NLRI) format, and the same procedures 282 of MVPN with only a few adaptions. It support for both IPv4 and IPv6 283 multicast flows over either an IPv4 or IPv6 SP infrastructure. GTM 284 over BIERv6 core is obviously a case of IPv4/IPv6 multicast over an 285 IPv6 SP infrastructure with BIERv6 data-plane. 287 The BIER (Type 11) PTA attribute and the BGP Prefix-SID attribute are 288 carried in the x-PMSI A-D route in GTM cases. When the a BGP-MVPN 289 x-PMSI A-D route is received by Egress PE, it is stored locally, and 290 the Src.DTx IPv6 Address of the Ingress PE in the route is used to 291 determine the VRF of a packet, which is the 'public' VRF in the case 292 of GTM. 294 There are some other attributes listed below for GTM over a BIERv6 295 core: 297 o Route Distinguishers - the RD field of a BGP-MVPN route's NLRI 298 MUST be set to zero (i.e., to 64 bits of zero) to represent a Non- 299 VPN GTM. See section 2.2 of [RFC7716]. 301 o Route Targets Extended Community (EC) - The RT EC carried by the 302 BGP-MVPN C-multicast (Type 6 or 7) route or Leaf A-D (Type 4) 303 route MUST be an IPv6-address-specific Extended Community (EC). 304 The Global Administrator field identifies the Upstream PE or the 305 UMH, and the Local Administrator field MUST always be set to zero 306 in GTM case. 308 o VRF Route Import Extended Community (EC) - The VRF Route Import EC 309 carried by IPv4 or IPv6 routes (SAFI 1 or 4) or multicast routes 310 (SAFI 2) is an IPv6 Address Specific Extended Community. 312 GTM IPv4 multicast over an BIERv6 core may be considered an 313 alternative to support IPv4 IPTV content delivery during transition 314 to IPv6 period comparing to [RFC8114]. They both use IPv4-in-IPv6 315 encapsulation, while BIERv6 uses an additional BIER header within an 316 IPv6 Extension header to support stateless core. 318 6. Data Plane 320 6.1. Encapsulation of Multicast Traffic 322 BIER IPv6 encapsulation (BIERv6) [I-D.xie-bier-ipv6-encapsulation] is 323 used for forwarding the c-multicast traffic through an IPv6 core. 324 The following diagram shows the progression of an MVPN c-multicast 325 packet as it enters and leaves the intra-AS service-provider network. 327 +---------------+ +---------------+ 328 | P-IPv6 Header | | P-IPv6 Header | 329 | (SA=Src.DTx | | (SA=Src.DTx | 330 | DA=End.BIER) | | DA=End.BIER) | 331 +---------------+ +---------------+ 332 | P-IPv6 ExtHdr | | P-IPv6 ExtHdr | 333 | (BIER header) | | (BIER header) | 334 ++=========++ ++=============++ ++=============++ ++=========++ 335 ||C-IP Hdr || || C-IP Hdr || || C-IP Hdr || ||C-IP Hdr || 336 ++=========++ >> ++=============++ >> ++=============++ >> ++=========++ 337 ||C-Payload|| || C-Payload || || C-Payload || ||C-Payload|| 338 ++=========++ ++=============++ ++=============++ ++=========++ 339 CE1-----------PE1------------------P2------------------PE2-----------CE2 341 Figure 1: BIERv6 MVPN/GTM Intra-AS 343 The Src.DTx SHOULD support as destination address of an ICMPv6 344 packet. If a loopback address of the BFR is used as Src.DTx address, 345 this is supported. If an address from an SRv6 locator is used as 346 Src.DTx address, the following pseudo-code describes how a packet 347 with Src.DTx as destination address is handled: 349 1. IF Last_NH = ICMPv6 ;;Ref1 350 2. Send to CPU. 351 3. ELSE 352 4. Drop the packet. 354 Ref1: ICMPv6 packet using Src.DT4, Src.DT6 or Src.DT46 as destination 355 address. 357 6.2. MTU 359 Each BFIR is expected to know the Maximum Transmission Unit (MTU) of 360 the BIER domain and the size of the BIERv6 encapsulation, thus each 361 BFIR can deduce the maximum size of the payload that can be 362 encapsulated in a BIERv6 packet. The section 3 of [RFC8296] applies. 364 6.3. TTL 366 The ingress PE (BFIR) should not copy the Time to Live (TTL) field 367 from the payload IP header received from a CE router to the delivery 368 IP header. Setting the TTL of the delivery IP header is determined 369 by the local policy of the ingress PE (BFIR) router per section 3 of 370 [RFC8296]. 372 7. Security Considerations 374 The security considerations defined in [RFC8556] and 375 [I-D.xie-bier-ipv6-encapsulation] apply equally to this document. 377 8. IANA Considerations 379 Allocation is expected from IANA for the following Src.DTx functions 380 codepoints from the "SRv6 Endpoint Behaviors" sub-registry. 382 Values 68, 69, 70 is suggested for Src.DT6, Src.DT4, Src.DT46 383 respectively. 385 +-------+--------+--------------------------+------------+ 386 | Value | Hex | Endpoint function | Reference | 387 +-------+--------+--------------------------+------------+ 388 | TBD | TBD | Src.DT6 | This draft | 389 +-------+--------+--------------------------+------------+ 390 | TBD | TBD | Src.DT4 | This draft | 391 +-------+--------+--------------------------+------------+ 392 | TBD | TBD | Src.DT46 | This draft | 393 +-------+--------+--------------------------+------------+ 395 Src.DT6 Source address for decapsulation and IPv6 table lookup 396 e.g. IPv6-MVPN (equivalent to per-VRF VPN label in RFC8556) 397 Src.DT4 Source address for decapsulation and IPv4 table lookup 398 e.g. IPv4-MVPN (equivalent to per-VRF VPN label in RFC8556) 399 Src.DT46 Source address for decapsulation and IP table lookup 400 e.g. IP-MVPN (equivalent to per-VRF VPN label) 402 9. Acknowledgements 404 The authors would like to thank Jeffrey Zhang for his useful 405 comments. 407 10. References 409 10.1. Normative References 411 [I-D.ietf-bess-srv6-services] 412 Dawra, G., Filsfils, C., Raszuk, R., Decraene, B., Zhuang, 413 S., and J. Rabadan, "SRv6 BGP based Overlay services", 414 draft-ietf-bess-srv6-services-04 (work in progress), July 415 2020. 417 [I-D.ietf-spring-srv6-network-programming] 418 Filsfils, C., Camarillo, P., Leddy, J., Voyer, D., 419 Matsushima, S., and Z. Li, "SRv6 Network Programming", 420 draft-ietf-spring-srv6-network-programming-24 (work in 421 progress), October 2020. 423 [I-D.xie-bier-ipv6-encapsulation] 424 Xie, J., Geng, L., McBride, M., Asati, R., Dhanaraj, S., 425 Zhu, Y., Qin, Z., Shin, M., Mishra, G., and X. Geng, 426 "Encapsulation for BIER in Non-MPLS IPv6 Networks", draft- 427 xie-bier-ipv6-encapsulation-08 (work in progress), July 428 2020. 430 [RFC6515] Aggarwal, R. and E. Rosen, "IPv4 and IPv6 Infrastructure 431 Addresses in BGP Updates for Multicast VPN", RFC 6515, 432 DOI 10.17487/RFC6515, February 2012, 433 . 435 [RFC6625] Rosen, E., Ed., Rekhter, Y., Ed., Hendrickx, W., and R. 436 Qiu, "Wildcards in Multicast VPN Auto-Discovery Routes", 437 RFC 6625, DOI 10.17487/RFC6625, May 2012, 438 . 440 [RFC7716] Zhang, J., Giuliano, L., Rosen, E., Ed., Subramanian, K., 441 and D. Pacella, "Global Table Multicast with BGP Multicast 442 VPN (BGP-MVPN) Procedures", RFC 7716, 443 DOI 10.17487/RFC7716, December 2015, 444 . 446 [RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., 447 Przygienda, T., and S. Aldrin, "Multicast Using Bit Index 448 Explicit Replication (BIER)", RFC 8279, 449 DOI 10.17487/RFC8279, November 2017, 450 . 452 [RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A., 453 Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation 454 for Bit Index Explicit Replication (BIER) in MPLS and Non- 455 MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January 456 2018, . 458 [RFC8556] Rosen, E., Ed., Sivakumar, M., Przygienda, T., Aldrin, S., 459 and A. Dolganow, "Multicast VPN Using Bit Index Explicit 460 Replication (BIER)", RFC 8556, DOI 10.17487/RFC8556, April 461 2019, . 463 10.2. Informative References 465 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 466 Requirement Levels", BCP 14, RFC 2119, 467 DOI 10.17487/RFC2119, March 1997, 468 . 470 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 471 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 472 May 2017, . 474 Authors' Addresses 476 Jingrong Xie 477 Huawei Technologies 479 Email: xiejingrong@huawei.com 481 Mike McBride 482 Futurewei 484 Email: mmcbride7@gmail.com 486 Senthil Dhanaraj 487 Huawei Technologies 489 Email: senthil.dhanaraj@huawei.com 491 Liang Geng 492 China Mobile 494 Email: gengliang@chinamobile.com 496 Gyan Mishra 497 Verizon Inc. 499 Email: gyan.s.mishra@verizon.com