idnits 2.17.00 (12 Aug 2021) /tmp/idnits31196/draft-ietf-nvo3-mcast-framework-10.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- == There are 1 instance of lines with multicast IPv4 addresses in the document. If these are generic example addresses, they should be changed to use the 233.252.0.x range defined in RFC 5771 Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == Line 491 has weird spacing: '...es, the multi...' -- The document date (October 5, 2017) is 1688 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- No issues found here. Summary: 0 errors (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 NVO3 working group A. Ghanwani 2 Internet Draft Dell 3 Intended status: Informational L. Dunbar 4 Expires: November 8, 2018 M. McBride 5 Huawei 6 V. Bannai 7 Google 8 R. Krishnan 9 Dell 11 October 5, 2017 13 A Framework for Multicast in Network Virtualization Overlays 14 draft-ietf-nvo3-mcast-framework-10 16 Status of this Memo 18 This Internet-Draft is submitted in full conformance with the 19 provisions of BCP 78 and BCP 79. 21 This Internet-Draft is submitted in full conformance with the 22 provisions of BCP 78 and BCP 79. This document may not be modified, 23 and derivative works of it may not be created, except to publish it 24 as an RFC and to translate it into languages other than English. 26 Internet-Drafts are working documents of the Internet Engineering 27 Task Force (IETF), its areas, and its working groups. Note that 28 other groups may also distribute working documents as Internet- 29 Drafts. 31 Internet-Drafts are draft documents valid for a maximum of six 32 months and may be updated, replaced, or obsoleted by other documents 33 at any time. It is inappropriate to use Internet-Drafts as 34 reference material or to cite them other than as "work in progress." 36 The list of current Internet-Drafts can be accessed at 37 http://www.ietf.org/ietf/1id-abstracts.txt 39 The list of Internet-Draft Shadow Directories can be accessed at 40 http://www.ietf.org/shadow.html 42 This Internet-Draft will expire on November 8, 2016. 44 Internet-Draft A framework for multicast in NVO3 46 Copyright Notice 48 Copyright (c) 2017 IETF Trust and the persons identified as the 49 document authors. All rights reserved. 51 This document is subject to BCP 78 and the IETF Trust's Legal 52 Provisions Relating to IETF Documents 53 (http://trustee.ietf.org/license-info) in effect on the date of 54 publication of this document. Please review these documents 55 carefully, as they describe your rights and restrictions with 56 respect to this document. Code Components extracted from this 57 document must include Simplified BSD License text as described in 58 Section 4.e of the Trust Legal Provisions and are provided without 59 warranty as described in the Simplified BSD License. 61 Abstract 63 This document provides a framework of supporting multicast traffic 64 in a network that uses Network Virtualization Overlays (NVO3). Both 65 infrastructure multicast and application-specific multicast are 66 discussed. It describes the various mechanisms that can be used for 67 delivering such traffic as well as the data plane and control plane 68 considerations for each of the mechanisms. 70 Table of Contents 72 1. Introduction...................................................3 73 1.1. Infrastructure multicast..................................3 74 1.2. Application-specific multicast............................4 75 1.3. Terminology clarification.................................4 76 2. Acronyms.......................................................4 77 3. Multicast mechanisms in networks that use NVO3.................5 78 3.1. No multicast support......................................6 79 3.2. Replication at the source NVE.............................6 80 3.3. Replication at a multicast service node...................9 81 3.4. IP multicast in the underlay.............................10 82 3.5. Other schemes............................................12 83 4. Simultaneous use of more than one mechanism...................12 84 5. Other issues..................................................12 85 5.1. Multicast-agnostic NVEs..................................13 86 5.2. Multicast membership management for DC with VMs..........13 87 6. Summary.......................................................14 88 7. Security Considerations.......................................14 89 8. IANA Considerations...........................................14 91 Internet-Draft A framework for multicast in NVO3 93 9. References....................................................14 94 9.1. Normative References.....................................14 95 9.2. Informative References...................................15 96 10. Acknowledgments..............................................16 98 1. Introduction 100 Network virtualization using Overlays over Layer 3 (NVO3)[RFC7365] 101 is a technology that is used to address issues that arise in 102 building large, multitenant data centers that make extensive use of 103 server virtualization [RFC7364]. 105 This document provides a framework for supporting multicast traffic, 106 in a network that uses Network Virtualization using Overlays over 107 Layer 3 (NVO3). Both infrastructure multicast and application- 108 specific multicast are considered. It describes the various 109 mechanisms and considerations that can be used for delivering such 110 traffic in networks that use NVO3. 112 The reader is assumed to be familiar with the terminology as defined 113 in the NVO3 Framework document [RFC7365] and NVO3 Architecture 114 document [RFC8014]. 116 1.1. Infrastructure multicast 118 Infrastructure multicast is a capability needed by networking 119 services, such as Address Resolution Protocol (ARP), Neighbor 120 Discovery (ND), Dynamic Host Configuration Protocol (DHCP), 121 multicast Domain Name Server (mDNS), etc. RFC3819 Section 5 and 6 122 have detailed description for some of the infrastructure multicast 123 [RFC3819]. It is possible to provide solutions for these that do 124 not involve multicast in the underlay network. In the case of 125 ARP/ND, a network virtualization authority (NVA) can be used for 126 distributing the mappings of IP address to MAC address to all 127 network virtualization edges (NVEs). The NVEs can then trap ARP 128 Request/ND Neighbor Solicitation messages from the TSs (Tenant 129 System) that are attached to it and respond to them, thereby 130 eliminating the need to for broadcast/multicast of such messages. 131 In the case of DHCP, the NVE can be configured to forward these 132 messages using a helper function. 134 Of course it is possible to support all of these infrastructure 135 multicast protocols natively if the underlay provides multicast 136 transport. However, even in the presence of multicast transport, it 137 may be beneficial to use the optimizations mentioned above to reduce 138 the amount of such traffic in the network. 140 Internet-Draft A framework for multicast in NVO3 142 1.2. Application-specific multicast 144 Application-specific multicast traffic are originated and consumed 145 by user applications. The Application-specific multicast, which can 146 be either Source-Specific Multicast (SSM) or Any-Source Multicast 147 (ASM)[RFC3569], has the following characteristics: 149 1. Receiver hosts are expected to subscribe to multicast content 150 using protocols such as IGMP [RFC3376] (IPv4) or MLD [RFC2710] 151 (IPv6). Multicast sources and listeners participant in these 152 protocols using addresses that are in the Tenant System address 153 domain. 155 2. The list of multicast listeners for each multicast group is not 156 known in advance. Therefore, it may not be possible for an NVA 157 to get the list of participants for each multicast group ahead 158 of time. 160 1.3. Terminology clarification 162 2. Acronyms & Terminology 164 In this document, the terms host, tenant system (TS) and virtual 165 machine (VM) are used interchangeably to represent an end station 166 that originates or consumes data packets. 168 ASM: Any-Source Multicast 170 IGMP: Internet Group Management Protocol 172 LISP: Locator/ID Separation Protocol 174 MSN: Multicast Service Node 176 RLOC: Routing Locator 178 NVA: Network Virtualization Authority 180 NVE: Network Virtualization Edge 182 NVGRE: Network Virtualization using GRE 184 Internet-Draft A framework for multicast in NVO3 186 PIM: Protocol-Independent Multicast 188 SSM: Source-Specific Multicast 190 TS: Tenant system 192 VM: Virtual Machine 194 VN: Virtual Network 196 VTEP: VxLAN Tunnel End Points 198 VXLAN: Virtual eXtensible LAN 200 3. Multicast mechanisms in networks that use NVO3 202 In NVO3 environments, traffic between NVEs is transported using an 203 encapsulation such as Virtual eXtensible Local Area Network (VXLAN) 204 [RFC7348,VXLAN-GPE], Network Virtualization Using Generic Routing 205 Encapsulation (NVGRE) [RFC7637], Geneve [Geneve], Generic UDP 206 Encapsulation (GUE) [GUE], etc. 208 What makes NVO3 different from any other network is that some NVEs, 209 especially the NVE implemented on server, might not support PIM or 210 other native multicast mechanisms. They might just encapsulate the 211 data packets from VMs with an outer unicast header. Therefore, it is 212 important for networks using NVO3 to have mechanisms to support 213 multicast as a network capability for NVEs, to map multicast traffic 214 from VMs (users/applications) to an equivalent multicast capability 215 inside the NVE, or to figure out the outer destination address if 216 NVE does not support native multicast (e.g. PIM) or IGMP. 218 Besides the need to support ARP and ND, there are several 219 applications that require the support of multicast and/or broadcast 220 in data centers [DC-MC]. With NVO3, there are many possible ways 221 that multicast may be handled in such networks. We discuss some of 222 the attributes of the following four methods: 224 1. No multicast support. 226 2. Replication at the source NVE. 228 3. Replication at a multicast service node. 230 4. IP multicast in the underlay. 232 Internet-Draft A framework for multicast in NVO3 234 These methods are briefly mentioned in the NVO3 Framework [RFC7365] 235 and NVO3 architecture [RFC8014] document. This document provides 236 more details about the basic mechanisms underlying each of these 237 methods and discusses the issues and trade-offs of each. 239 We note that other methods are also possible, such as [EDGE-REP], 240 but we focus on the above four because they are the most common. 242 3.1. No multicast support 244 In this scenario, there is no support whatsoever for multicast 245 traffic when using the overlay. This method can only work if the 246 following conditions are met: 248 1. All of the application traffic in the network is unicast 249 traffic and the only multicast/broadcast traffic is from ARP/ND 250 protocols. 252 2. An NVA is used by the NVEs to determine the mapping of a given 253 Tenant System's (TS's) MAC/IP address to its NVE. In other 254 words, there is no data plane learning. Address resolution 255 requests via ARP/ND that are issued by the TSs must be resolved 256 by the NVE that they are attached to. 258 With this approach, it is not possible to support application- 259 specific multicast. However, certain multicast/broadcast 260 applications such as DHCP can be supported by use of a helper 261 function in the NVE. 263 The main drawback of this approach, even for unicast traffic, is 264 that it is not possible to initiate communication with a TS for 265 which a mapping to an NVE does not already exist in the NVA. This 266 is a problem in the case where the NVE is implemented in a physical 267 switch and the TS is a physical end station that has not registered 268 with the NVA. 270 3.2. Replication at the source NVE 272 With this method, the overlay attempts to provide a multicast 273 service without requiring any specific support from the underlay, 274 other than that of a unicast service. A multicast or broadcast 275 transmission is achieved by replicating the packet at the source 277 Internet-Draft A framework for multicast in NVO3 279 NVE, and making copies, one for each destination NVE that the 280 multicast packet must be sent to. 282 For this mechanism to work, the source NVE must know, a priori, the 283 IP addresses of all destination NVEs that need to receive the 284 packet. For the purpose of ARP/ND, this would involve knowing the 285 IP addresses of all the NVEs that have TSs in the virtual network 286 (VN) of the TS that generated the request. For the support of 287 application-specific multicast traffic, a method similar to that of 288 receiver-sites registration for a particular multicast group 289 described in [LISP-Signal-Free] can be used. The registrations from 290 different receiver-sites can be merged at the NVA, which can 291 construct a multicast replication-list inclusive of all NVEs to 292 which receivers for a particular multicast group are attached. The 293 replication-list for each specific multicast group is maintained by 294 the NVA. Note: Using LISP-signal-free does not necessarily mean the 295 head-end (i.e. NVE) must do replication. If the mapping database 296 (i.e. NVA) indicates that packets are encapsulated to multicast 297 RLOCs, then there is no replication happening at the NVE. 299 The receiver-sites registration is achieved by egress NVEs 300 performing the IGMP/MLD snooping to maintain state for which 301 attached TSs have subscribed to a given IP multicast group. When 302 the members of a multicast group are outside the NVO3 domain, it is 303 necessary for NVO3 gateways to keep track of the remote members of 304 each multicast group. The NVEs and NVO3 gateways then communicate 305 the multicast groups that are of interest to the NVA. If the 306 membership is not communicated to the NVA, and if it is necessary to 307 prevent hosts attached to an NVE that have not subscribed to a 308 multicast group from receiving the multicast traffic, the NVE would 309 need to maintain multicast group membership information. 311 In the absence of IGMP/MLD snooping, the traffic would be delivered 312 to all TSs that are part of the VN. 314 In multi-homing environments, i.e., in those where a TS is attached 315 to more than one NVE, the NVA would be expected to provide 316 information to all of the NVEs under its control about all of the 317 NVEs to which such a TS is attached. The ingress NVE can choose any 318 one of the egress NVEs for the data frames destined towards the TS. 320 This method requires multiple copies of the same packet to all NVEs 321 that participate in the VN. If, for example, a tenant subnet is 322 spread across 50 NVEs, the packet would have to be replicated 50 323 times at the source NVE. Obviously, this approach creates more 324 traffic to the network that can cause congestion when the network 326 Internet-Draft A framework for multicast in NVO3 328 load is high. This also creates an issue with the forwarding 329 performance of the NVE. 331 Note that this method is similar to what was used in Virtual Private 332 LAN Service (VPLS) [RFC4762] prior to support of Multi-Protocol 333 Label Switching (MPLS) multicast [RFC7117]. While there are some 334 similarities between MPLS Virtual Private Network (VPN) and NVO3, 335 there are some key differences: 337 - The Customer Edge (CE) to Provider Edge (PE) attachment in VPNs is 338 somewhat static, whereas in a DC that allows VMs to migrate 339 anywhere, the TS attachment to NVE is much more dynamic. 341 - The number of PEs to which a single VPN customer is attached in 342 an MPLS VPN environment is normally far less than the number of 343 NVEs to which a VN's VMs are attached in a DC. 345 When a VPN customer has multiple multicast groups, "Multicast VPN" 346 [RFC6513] combines all those multicast groups within each VPN 347 client to one single multicast group in the MPLS (or VPN) core. 348 The result is that messages from any of the multicast groups 349 belonging to one VPN customer will reach all the PE nodes of the 350 client. In other words, any messages belonging to any multicast 351 groups under customer X will reach all PEs of the customer X. When 352 the customer X is attached to only a handful of PEs, the use of 353 this approach does not result in excessive wastage of bandwidth in 354 the provider's network. 356 In a DC environment, a typical server/hypervisor based virtual 357 switch may only support 10's VMs (as of this writing). A subnet 358 with N VMs may be, in the worst case, spread across N vSwitches. 359 Using "MPLS VPN multicast" approach in such a scenario would 360 require the creation of a Multicast group in the core for this VN 361 to reach all N NVEs. If only small percentage of this client's VMs 362 participate in application specific multicast, a great number of 363 NVEs will receive multicast traffic that is not forwarded to any 364 of their attached VMs, resulting in considerable wastage of 365 bandwidth. 367 Therefore, the Multicast VPN solution may not scale in DC 368 environment with dynamic attachment of Virtual Networks to NVEs and 369 greater number of NVEs for each virtual network. 371 Internet-Draft A framework for multicast in NVO3 373 3.3. Replication at a multicast service node 375 With this method, all multicast packets would be sent using a 376 unicast tunnel encapsulation from the ingress NVE to a multicast 377 service node (MSN). The MSN, in turn, would create multiple copies 378 of the packet and would deliver a copy, using a unicast tunnel 379 encapsulation, to each of the NVEs that are part of the multicast 380 group for which the packet is intended. 382 This mechanism is similar to that used by the Asynchronous Transfer 383 Mode (ATM) Forum's LAN Emulation (LANE) specification [LANE]. The 384 MSN is similar to the RP (Rendezvous Point) in PIM SM, but different 385 in that the user data traffic are carried by the NVO3 tunnels. 387 The following are the possible ways for the MSN to get the 388 membership information for each multicast group: 390 - The MSN can obtain this membership information from the IGMP/MLD 391 report messages sent by TSs in response to IGMP/MLD query messages 392 from the MSN. The IGMP/MLD query messages are sent from the MSN to 393 the NVEs, which then forward the query messages to TSs attached to 394 them. An IGMP/MLD query messages sent out by the MSN to an NVE is 395 encapsulated with the MSN address in the outer source address 396 field and the address of the NVE in the outer destination address 397 field. The encapsulated IGMP/MLD query messages also has a VNID 398 for a virtual network (VN) that TSs belong in the outer header and 399 a multicast address in the inner destination address field. Upon 400 receiving the encapsulated IGMP/MLD query message, the NVE 401 establishes a mapping "MSN address" <-> "multicast address", 402 decapsulates the received encapsulated IGMP/MLD message, and 403 multicast the decapsulated query message to TSs that belong to the 404 VN under the NVE. A IGMP/MLD report message sent by a TS includes 405 the multicast address and the address of the TS. With the proper 406 "MSN Address" <-> "Multicast-Address" mapping, the NVEs can 407 encapsulate all multicast data frames to the "Multicast-Address" 408 with the address of the MSN in the outer destination address 409 field. 411 Internet-Draft A framework for multicast in NVO3 413 - The MSN can obtain the membership information from the NVEs that 414 have the capability to establish multicast groups by snooping 415 native IGMP/MLD messages (p.s. the communication must be specific 416 to the multicast addresses), or by having the NVA obtain the 417 information from the NVEs, and in turn have MSN communicate with 418 the NVA. This approach requires additional protocol between MSN 419 and NVEs. 421 Unlike the method described in Section 3.2, there is no performance 422 impact at the ingress NVE, nor are there any issues with multiple 423 copies of the same packet from the source NVE to the Multicast 424 Service Node. However, there remain issues with multiple copies of 425 the same packet on links that are common to the paths from the MSN 426 to each of the egress NVEs. Additional issues that are introduced 427 with this method include the availability of the MSN, methods to 428 scale the services offered by the MSN, and the sub-optimality of the 429 delivery paths. 431 Finally, the IP address of the source NVE must be preserved in 432 packet copies created at the multicast service node if data plane 433 learning is in use. This could create problems if IP source address 434 reverse path forwarding (RPF) checks are in use. 436 3.4. IP multicast in the underlay 438 In this method, the underlay supports IP multicast and the ingress 439 NVE encapsulates the packet with the appropriate IP multicast 440 address in the tunnel encapsulation header for delivery to the 441 desired set of NVEs. The protocol in the underlay could be any 442 variant of Protocol Independent Multicast (PIM), or protocol 443 dependent multicast, such as [ISIS-Multicast]. 445 If an NVE connects to its attached TSs via a Layer 2 network, there 446 are multiple ways for NVEs to support the application specific 447 multicast: 449 - The NVE only supports the basic IGMP/MLD snooping function, let 450 the TSs routers handling the application specific multicast. This 451 scheme doesn't utilize the underlay IP multicast protocols. 453 Internet-Draft A framework for multicast in NVO3 455 - The NVE can act as a pseudo multicast router for the directly 456 attached VMs and support proper mapping of IGMP/MLD's messages to 457 the messages needed by the underlay IP multicast protocols. 459 With this method, there are none of the issues with the methods 460 described in Sections 3.2. 462 With PIM Sparse Mode (PIM-SM), the number of flows required would be 463 (n*g), where n is the number of source NVEs that source packets for 464 the group, and g is the number of groups. Bidirectional PIM (BIDIR- 465 PIM) would offer better scalability with the number of flows 466 required being g. Unfortunately, many vendors still do not fully 467 support BIDIR or have limitations on its implementation. RFC6831 468 [RFC6831] has good description of using SSM as an alternative to 469 BIDIR if the VTEP/NVE devices have a way to learn of each other's IP 470 address so that they could join all SSM SPT's to create/maintain an 471 underlay SSM IP Multicast tunnel solution. 473 In the absence of any additional mechanism, e.g. using an NVA for 474 address resolution, for optimal delivery, there would have to be a 475 separate group for each tenant, plus a separate group for each 476 multicast address (used for multicast applications) within a tenant. 478 Additional considerations are that only the lower 23 bits of the IP 479 address (regardless of whether IPv4 or IPv6 is in use) are mapped to 480 the outer MAC address, and if there is equipment that prunes 481 multicasts at Layer 2, there will be some aliasing. Finally, a 482 mechanism to efficiently provision such addresses for each group 483 would be required. 485 There are additional optimizations which are possible, but they come 486 with their own restrictions. For example, a set of tenants may be 487 restricted to some subset of NVEs and they could all share the same 488 outer IP multicast group address. This however introduces a problem 489 of sub-optimal delivery (even if a particular tenant within the 490 group of tenants doesn't have a presence on one of the NVEs which 491 another one does, the multicast packets would still be delivered to 492 that NVE). It also introduces an additional network management 493 burden to optimize which tenants should be part of the same tenant 494 group (based on the NVEs they share), which somewhat dilutes the 496 Internet-Draft A framework for multicast in NVO3 498 value proposition of NVO3 which is to completely decouple the 499 overlay and physical network design allowing complete freedom of 500 placement of VMs anywhere within the data center. 502 Multicast schemes such as BIER (Bit Indexed Explicit Replication) 503 [BIER-ARCH] may be able to provide optimizations by allowing the 504 underlay network to provide optimum multicast delivery without 505 requiring routers in the core of the network to maintain per- 506 multicast group state. 508 3.5. Other schemes 510 There are still other mechanisms that may be used that attempt to 511 combine some of the advantages of the above methods by offering 512 multiple replication points, each with a limited degree of 513 replication [EDGE-REP]. Such schemes offer a trade-off between the 514 amount of replication at an intermediate node (e.g. router) versus 515 performing all of the replication at the source NVE or all of the 516 replication at a multicast service node. 518 4. Simultaneous use of more than one mechanism 520 While the mechanisms discussed in the previous section have been 521 discussed individually, it is possible for implementations to rely 522 on more than one of these. For example, the method of Section 3.1 523 could be used for minimizing ARP/ND, while at the same time, 524 multicast applications may be supported by one, or a combination of, 525 the other methods. For small multicast groups, the methods of 526 source NVE replication or the use of a multicast service node may be 527 attractive, while for larger multicast groups, the use of multicast 528 in the underlay may be preferable. 530 5. Other issues 531 Internet-Draft A framework for multicast in NVO3 533 5.1. Multicast-agnostic NVEs 535 Some hypervisor-based NVEs do not process or recognize IGMP/MLD 536 frames; i.e. those NVEs simply encapsulate the IGMP/MLD messages in 537 the same way as they do for regular data frames. 539 By default, TSs router periodically sends IGMP/MLD query messages to 540 all the hosts in the subnet to trigger the hosts that are interested 541 in the multicast stream to send back IGMP/MLD reports. In order for 542 the MSN to get the updated multicast group information, the MSN can 543 also send the IGMP/MLD query message comprising a client specific 544 multicast address, encapsulated in an overlay header to all the NVEs 545 to which the TSs in the VN are attached. 547 However, the MSN may not always be aware of the client specific 548 multicast addresses. In order to perform multicast filtering, the 549 MSN has to snoop the IGMP/MLD messages between TSs and their 550 corresponding routers to maintain the multicast membership. In order 551 for the MSN to snoop the IGMP/MLD messages between TSs and their 552 router, the NVA needs to configure the NVE to send copies of the 553 IGMP/MLD messages to the MSN in addition to the default behavior of 554 sending them to the TSs' routers; e.g. the NVA has to inform the 555 NVEs to encapsulate data frames with DA being 224.0.0.2 (destination 556 address of IGMP report) to TSs' router and MSN. 558 This process is similar to "Source Replication" described in Section 559 3.2, except the NVEs only replicate the message to TSs' router and 560 MSN. 562 5.2. Multicast membership management for DC with VMs 564 For data centers with virtualized servers, VMs can be added, deleted 565 or moved very easily. When VMs are added, deleted or moved, the NVEs 566 to which the VMs are attached are changed. 568 When a VM is deleted from an NVE or a new VM is added to an NVE, the 569 VM management system should notify the MSN to send the IGMP/MLD 570 query messages to the relevant NVEs (as described in Section 3.3), 571 so that the multicast membership can be updated promptly. 572 Otherwise, if there are changes of VMs attachment to NVEs, within 573 the duration of the configured default time interval that the TSs 574 routers use for IGMP/MLD queries, multicast data may not reach the 575 VM(s) that moved. 577 Internet-Draft A framework for multicast in NVO3 579 6. Summary 581 This document has identified various mechanisms for supporting 582 application specific multicast in networks that use NVO3. It 583 highlights the basics of each mechanism and some of the issues with 584 them. As solutions are developed, the protocols would need to 585 consider the use of these mechanisms and co-existence may be a 586 consideration. It also highlights some of the requirements for 587 supporting multicast applications in an NVO3 network. 589 7. Security Considerations 591 This draft does not introduce any new security considerations beyond 592 what is described n NVO3 Architecture (RFC8014). 594 8. IANA Considerations 596 This document requires no IANA actions. RFC Editor: Please remove 597 this section before publication. 599 9. References 601 9.1. Normative References 603 [RFC3376] Cain B. et al. "Internet Group Management Protocol, 604 Version 3", October 2002. 606 [RFC6513] Rosen, E. et al., "Multicast in MPLS/BGP IP VPNs", 607 February 2012. 609 [RFC7364] Narten, T. et al., "Problem statement: Overlays for 610 network virtualization", October 2014. 612 [RFC7365] Lasserre, M. et al., "Framework for data center (DC) 613 network virtualization", October 2014. 615 [RFC8014] Narten, T. et al.," An Architecture for Overlay Networks 616 (NVO3)", RFC8014, Dec. 2016. 618 Internet-Draft A framework for multicast in NVO3 620 9.2. Informative References 622 [RFC2710] S. Deering et al, "Multicast Listener Discovery (MLD) for 623 IPv6", Oct 1999. 625 [RFC3569] S. Bhattacharyya, Ed., "An Overview of Source-Specific 626 Multicast (SSM)", July 2003. 628 [RFC3819] P. Harn et al., "Advice for Internet Subnetwork 629 Designers", July 2004. 631 [RFC4762] Lasserre, M., and Kompella, V. (Eds.), "Virtual Private 632 LAN Service (VPLS) using Label Distribution Protocol (LDP) 633 signaling," January 2007. 635 [RFC6831] Farinacci, D. et al., "The Locator/ID Seperation Protocol 636 (LISP) for Multicast Environments", Jan, 2013. 638 [RFC7117] Aggarwal, R. et al., "Multicast in VPLS," February 2014. 640 [RFC7348] Mahalingam, M. et al., " Virtual eXtensible Local Area 641 Network (VXLAN): A Framework for Overlaying Virtualized 642 Layer 2 Networks over Layer 3 Networks", August 2014. 644 [RFC7365] M. Lasserre, et al. "Framework for Data Center (DC) 645 Network Virtualization", Oct 2014. 647 [RFC7637] Garg P. and Wang, Y. (Eds.), "NVGRE: Network 648 Vvirtualization using Generic Routing Encapsulation", 649 September 2015. 651 [BIER-ARCH] 652 Wijnands, IJ. (Ed.) et al., "Multicast using Bit Index 653 Explicit Replication," , 654 January 2016. 656 [DC-MC] McBride, M. and Lui, H., "Multicast in the data center 657 overview," , work in 658 progress, July 2012. 660 [EDGE-REP] 662 Internet-Draft A framework for multicast in NVO3 664 Marques P. et al., "Edge multicast replication for BGP IP 665 VPNs," , work in 666 progress, June 2012. 668 [Geneve] 669 Gross, J. and Ganga, I. (Eds.), "Geneve: Generic Network 670 Virtualization Encapsulation", , work in progress, January 2016. 673 [GUE] 674 Herbert, T. et al., "Generic UDP Encapsulation", , work in progress, December 2015. 677 [ISIS-Multicast] 678 Yong, L. et al., "ISIS Protocol Extension for Building 679 Distribution Trees", , work in progress, October 2014. 682 [LANE] "LAN emulation over ATM," The ATM Forum, af-lane-0021.000, 683 January 1995. 685 [LISP-Signal-Free] 687 Moreno, V. and Farinacci, D., "Signal-Free LISP 688 Multicast", , 689 work in progress, April 2016. 691 [VXLAN-GPE] 693 Kreeger, L. and Elzur, U. (Eds.), "Generic Protocol 694 Extension for VXLAN", , work 695 in progress, April 2016. 697 10. Acknowledgments 699 Many thanks are due to Dino Farinacci, Erik Nordmark, Lucy Yong, 700 Nicolas Bouliane, Saumya Dikshit, Joe Touch, Olufemi Komolafe, and 701 Matthew Bocci, for their valuable comments and suggestions. 703 This document was prepared using 2-Word-v2.0.template.dot. 705 Internet-Draft A framework for multicast in NVO3 707 Authors' Addresses 709 Anoop Ghanwani 710 Dell 711 Email: anoop@alumni.duke.edu 713 Linda Dunbar 714 Huawei Technologies 715 5340 Legacy Drive, Suite 1750 716 Plano, TX 75024, USA 717 Phone: (469) 277 5840 718 Email: ldunbar@huawei.com 720 Mike McBride 721 Huawei Technologies 722 Email: mmcbride7@gmail.com 724 Vinay Bannai 725 Google 726 Email: vbannai@gmail.com 728 Ram Krishnan 729 Dell 730 Email: ramkri123@gmail.com