idnits 2.17.1 draft-ietf-bess-evpn-optimized-ir-04.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 2 instances of lines with control characters in the document. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (September 30, 2018) is 2007 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in RFCs) == Unused Reference: 'RFC7902' is defined on line 1082, but no explicit reference was found in the text == Outdated reference: A later version (-14) exists of draft-ietf-bess-evpn-bum-procedure-updates-04 Summary: 1 error (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 BESS Workgroup J. Rabadan, Ed. 3 Internet Draft S. Sathappan 4 Intended status: Standards Track Nokia 6 W. Lin 7 Juniper 9 M. Katiyar 10 Versa Networks 12 A. Sajassi 13 Cisco 15 Expires: April 3, 2019 September 30, 2018 17 Optimized Ingress Replication solution for EVPN 18 draft-ietf-bess-evpn-optimized-ir-04 20 Abstract 22 Network Virtualization Overlay (NVO) networks using EVPN as control 23 plane may use ingress replication (IR) or PIM-based trees to convey 24 the overlay BUM traffic. PIM provides an efficient solution to avoid 25 sending multiple copies of the same packet over the same physical 26 link, however it may not always be deployed in the NVO core network. 27 IR avoids the dependency on PIM in the NVO network core. While IR 28 provides a simple multicast transport, some NVO networks with 29 demanding multicast applications require a more efficient solution 30 without PIM in the core. This document describes a solution to 31 optimize the efficiency of IR in NVO networks. 33 Status of this Memo 35 This Internet-Draft is submitted in full conformance with the 36 provisions of BCP 78 and BCP 79. 38 Internet-Drafts are working documents of the Internet Engineering 39 Task Force (IETF), its areas, and its working groups. Note that 40 other groups may also distribute working documents as Internet- 41 Drafts. 43 Internet-Drafts are draft documents valid for a maximum of six months 44 and may be updated, replaced, or obsoleted by other documents at any 45 time. It is inappropriate to use Internet-Drafts as reference 46 material or to cite them other than as "work in progress." 48 The list of current Internet-Drafts can be accessed at 49 http://www.ietf.org/ietf/1id-abstracts.txt 51 The list of Internet-Draft Shadow Directories can be accessed at 52 http://www.ietf.org/shadow.html 54 This Internet-Draft will expire on April 3, 2019. 56 Copyright Notice 58 Copyright (c) 2018 IETF Trust and the persons identified as the 59 document authors. All rights reserved. 61 This document is subject to BCP 78 and the IETF Trust's Legal 62 Provisions Relating to IETF Documents 63 (http://trustee.ietf.org/license-info) in effect on the date of 64 publication of this document. Please review these documents 65 carefully, as they describe your rights and restrictions with respect 66 to this document. Code Components extracted from this document must 67 include Simplified BSD License text as described in Section 4.e of 68 the Trust Legal Provisions and are provided without warranty as 69 described in the Simplified BSD License. 71 Table of Contents 73 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 74 2. Solution requirements . . . . . . . . . . . . . . . . . . . . . 4 75 3. EVPN BGP Attributes for optimized-IR . . . . . . . . . . . . . 5 76 4. Non-selective Assisted-Replication (AR) Solution Description . 8 77 4.1. Non-selective AR-REPLICATOR procedures . . . . . . . . . . 8 78 4.2. Non-selective AR-LEAF procedures . . . . . . . . . . . . . 9 79 4.3. RNVE procedures . . . . . . . . . . . . . . . . . . . . . . 11 80 4.4. Forwarding behavior in non-selective AR EVIs . . . . . . . 11 81 4.4.1. Broadcast and Multicast forwarding behavior . . . . . . 11 82 4.4.1.1. Non-selective AR-REPLICATOR BM forwarding . . . . . 11 83 4.4.1.2. Non-selective AR-LEAF BM forwarding . . . . . . . . 12 84 4.4.1.3. RNVE BM forwarding . . . . . . . . . . . . . . . . 12 85 4.4.2. Unknown unicast forwarding behavior . . . . . . . . . . 13 86 4.4.2.1. Non-selective AR-REPLICATOR/LEAF Unknown unicast 87 forwarding . . . . . . . . . . . . . . . . . . . . 13 88 4.4.2.2. RNVE Unknown unicast forwarding . . . . . . . . . . 13 89 5. Selective Assisted-Replication (AR) Solution Description . . . 13 90 5.1. Selective AR-REPLICATOR procedures . . . . . . . . . . . . 14 91 5.2. Selective AR-LEAF procedures . . . . . . . . . . . . . . . 15 92 5.3. Forwarding behavior in selective AR EVIs . . . . . . . . . 16 93 5.3.1. Selective AR-REPLICATOR BM forwarding . . . . . . . . . 16 94 5.3.2. Selective AR-LEAF BM forwarding . . . . . . . . . . . . 17 95 6. Pruned-Flood-Lists (PFL) . . . . . . . . . . . . . . . . . . . 18 96 6.1. A PFL example . . . . . . . . . . . . . . . . . . . . . . . 18 97 7. AR Procedures for single-IP AR-REPLICATORS . . . . . . . . . . 19 98 8. AR Procedures and EVPN All-Active Multi-homing Split-Horizon . 20 99 8.1. Ethernet Segments on AR-LEAF nodes . . . . . . . . . . . . 20 100 8.2. Ethernet Segments on AR-REPLICATOR nodes . . . . . . . . . 21 101 9. Benefits of the optimized-IR solution . . . . . . . . . . . . . 21 102 10. Conventions used in this document . . . . . . . . . . . . . . 21 103 11. Security Considerations . . . . . . . . . . . . . . . . . . . 22 104 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22 105 13. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 22 106 14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 23 107 14.1 Normative References . . . . . . . . . . . . . . . . . . . 23 108 14.2 Informative References . . . . . . . . . . . . . . . . . . 24 109 15.0 Contributors . . . . . . . . . . . . . . . . . . . . . . . 24 110 16. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 24 111 17. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 24 113 1. Introduction 115 EVPN may be used as the control plane for a Network Virtualization 116 Overlay (NVO) network. Network Virtualization Edge (NVE) devices and 117 PEs that are part of the same EVI use Ingress Replication (IR) or 118 PIM-based trees to transport the tenant's BUM traffic. In NVO 119 networks where PIM-based trees cannot be used, IR is the only 120 alternative. Examples of these situations are NVO networks where the 121 core nodes don't support PIM or the network operator does not want to 122 run PIM in the core. 124 In some use-cases, the amount of replication for BUM (Broadcast, 125 Unknown unicast and Multicast traffic) is kept under control on the 126 NVEs due to the following fairly common assumptions: 128 a) Broadcast is greatly reduced due to the proxy-ARP and proxy-ND 129 capabilities supported by EVPN on the NVEs. Some NVEs can even 130 provide DHCP-server functions for the attached Tenant Systems (TS) 131 reducing the broadcast even further. 133 b) Unknown unicast traffic is greatly reduced in virtualized NVO 134 networks where all the MAC and IP addresses are learnt in the 135 control plane. 137 c) Multicast applications are not used. 139 If the above assumptions are true for a given NVO network, then IR 140 provides a simple solution for multi-destination traffic. However, 141 the statement c) above is not always true and multicast applications 142 are required in many use-cases. 144 When the multicast sources are attached to NVEs residing in 145 hypervisors or low-performance-replication TORs, the ingress 146 replication of a large amount of multicast traffic to a significant 147 number of remote NVEs/PEs can seriously degrade the performance of 148 the NVE and impact the application. 150 This document describes a solution that makes use of two IR 151 optimizations: 153 i) Assisted-Replication (AR) 154 ii) Pruned-Flood-Lists (PFL) 156 Both optimizations may be used together or independently so that the 157 performance and efficiency of the network to transport multicast can 158 be improved. Both solutions require some extensions to [RFC7432] that 159 are described in section 3. 161 Section 2 lists the requirements of the combined optimized-IR 162 solution, whereas sections 4 and 5 describe the Assisted-Replication 163 (AR) solution, and section 6 the Pruned-Flood-Lists (PFL) solution. 165 2. Solution requirements 167 The IR optimization solution (optimized-IR hereafter) MUST meet the 168 following requirements: 170 a) The solution MUST provide an IR optimization for BM (Broadcast and 171 Multicast) traffic, while preserving the packet order for unicast 172 applications, i.e. known and unknown unicast traffic SHALL follow 173 the same path. 175 b) The solution MUST be compatible with [RFC7432] and [RFC8365] and 176 have no impact on the EVPN procedures for BM traffic. In 177 particular, the solution SHOULD support the following EVPN 178 functions: 180 o All-active multi-homing, including the split-horizon and 181 Designated Forwarder (DF) functions. 183 o Single-active multi-homing, including the DF function. 185 o Handling of multi-destination traffic and processing of 186 broadcast and multicast as per [RFC7432]. 188 c) The solution MUST be backwards compatible with existing NVEs using 189 a non-optimized version of IR. A given EVI can have NVEs/PEs 190 supporting regular-IR and optimized-IR. 192 d) The solution MUST be independent of the NVO specific data plane 193 encapsulation and the virtual identifiers being used, e.g.: VXLAN 194 VNIs, NVGRE VSIDs or MPLS labels. 196 3. EVPN BGP Attributes for optimized-IR 198 This solution proposes some changes to the [RFC7432] Inclusive 199 Multicast Ethernet Tag routes and attributes so that an NVE/PE can 200 signal its optimized-IR capabilities. 202 The Inclusive Multicast Ethernet Tag route (RT-3) and its PMSI Tunnel 203 Attribute's (PTA) general format used in [RFC7432] are shown below: 205 +---------------------------------+ 206 | RD (8 octets) | 207 +---------------------------------+ 208 | Ethernet Tag ID (4 octets) | 209 +---------------------------------+ 210 | IP Address Length (1 octet) | 211 +---------------------------------+ 212 | Originating Router's IP Addr | 213 | (4 or 16 octets) | 214 +---------------------------------+ 216 +---------------------------------+ 217 | Flags (1 octet) | 218 +---------------------------------+ 219 | Tunnel Type (1 octets) | 220 +---------------------------------+ 221 | MPLS Label (3 octets) | 222 +---------------------------------+ 223 | Tunnel Identifier (variable) | 224 +---------------------------------+ 226 The Flags field is defined as follows: 228 0 1 2 3 4 5 6 7 229 +-+-+-+-+-+--+-+-+ 230 |rsved| T |BM|U|L| 231 +-+-+-+-+-+--+-+-+ 233 Where a new type field (for AR) and two new flags (for PFL signaling) 234 are defined: 236 - T is the AR Type field (2 bits) that defines the AR role of the 237 advertising router: 239 + 00 (decimal 0) = RNVE (non-AR support) 241 + 01 (decimal 1) = AR-REPLICATOR 243 + 10 (decimal 2) = AR-LEAF 245 + 11 (decimal 3) = RESERVED 247 - The PFL (Pruned-Flood-Lists) flags defined the desired behavior of 248 the advertising router for the different types of traffic: 250 + BM= Broadcast and Multicast (BM) flag. BM=1 means "prune-me" from 251 the BM flooding list. BM=0 means regular behavior. 253 + U= Unknown flag. U=1 means "prune-me" from the Unknown flooding 254 list. U=0 means regular behavior. 256 - Flag L is an existing flag defined in [RFC6514] (L=Leaf Information 257 Required) and it will be used only in the Selective AR Solution. 259 Please refer to section 10 for the IANA considerations related to the 260 PTA flags. 262 In this document, the above RT-3 and PTA can be used in two different 263 modes for the same EVI/Ethernet Tag: 265 o Regular-IR route: in this route, Originating Router's IP Address, 266 Tunnel Type (0x06), MPLS Label, Tunnel Identifier and Flags MUST be 267 used as described in [RFC7432]. The Originating Router's IP Address 268 and Tunnel Identifier are set to an IP address that we denominate 269 IR-IP in this document. 271 o Replicator-AR route: this route is used by the AR-REPLICATOR to 272 advertise its AR capabilities, with the fields set as follows. 274 + Originating Router's IP Address as well as the Tunnel Identifier 275 are set to the same routable IP address that we denominate AR-IP 276 and SHOULD be different than the IR-IP for a given PE/NVE. 278 + Tunnel Type = Assisted-Replication (AR). Section 11 provides the 279 allocated type value. 281 + T (AR role type) = 01 (AR-REPLICATOR). 283 + L (Leaf Information Required) = 0 (for non-selective AR) or 1 284 (for selective AR). 286 In addition, this document also uses the Leaf-AD route (RT-11) 287 defined in [EVPN-BUM] in case the selective AR mode is used. The 288 Leaf-AD route MAY be used by the AR-LEAF in response to a Replicator- 289 AR route (with the L flag set) to advertise its desire to receive the 290 multicast traffic from a specific AR-REPLICATOR. It is only used for 291 selective AR and its fields are set as follows: 293 + Originating Router's IP Address is set to the advertising IR-IP 294 (same IP used by the AR-LEAF in regular-IR routes). 296 + Route Key is the "Route Type Specific" NLRI of the Replicator-AR 297 route for which this Leaf-AD route is generated. 299 + The AR-LEAF constructs an IP-address-specific route-target as 300 indicated in [EVPN-BUM], by placing the IP address carried in the 301 Next Hop field of the received Replicator-AR route in the Global 302 Administrator field of the Community, with the Local 303 Administrator field of this Community set to 0. Note that the 304 same IP-address-specific import route-target is auto-configured 305 by the AR-REPLICATOR that sent the Replicator-AR, in order to 306 control the acceptance of the Leaf-AD routes. 308 + The leaf-AD route MUST include the PMSI Tunnel attribute with the 309 Tunnel Type set to AR, type set to AR-LEAF and the Tunnel 310 Identifier set to the IR-IP of the advertising AR-LEAF. The PMSI 311 Tunnel attribute MUST carry a downstream-assigned MPLS label that 312 is used by the AR-REPLICATOR to send traffic to the AR-LEAF. 314 Each AR-enabled node MUST understand and process the AR type field in 315 the PTA (Flags field) of the routes, and MUST signal the 316 corresponding type (1 or 2) according to its administrative choice. 318 Each node, part of the EVI, MAY understand and process the BM/U 319 flags. Note that these BM/U flags may be used to optimize the 320 delivery of multi-destination traffic and its use SHOULD be an 321 administrative choice, and independent of the AR role. 323 Non-optimized-IR nodes will be unaware of the new PMSI attribute flag 324 definition as well as the new Tunnel Type (AR), i.e. they will ignore 325 the information contained in the flags field for any RT-3 and will 326 ignore the RT-3 routes with an unknown Tunnel Type (type AR in this 327 case). 329 4. Non-selective Assisted-Replication (AR) Solution Description 331 The following figure illustrates an example NVO network where the 332 non-selective AR function is enabled. Three different roles are 333 defined for a given EVI: AR-REPLICATOR, AR-LEAF and RNVE (Regular 334 NVE). The solution is called "non-selective" because the chosen AR- 335 REPLICATOR for a given flow MUST replicate the multicast traffic to 336 'all' the NVE/PEs in the EVI except for the source NVE/PE. 338 ( ) 339 (_ WAN _) 340 +---(_ _)----+ 341 | (_ _) | 342 PE1 | PE2 | 343 +------+----+ +----+------+ 344 TS1--+ (EVI-1) | | (EVI-1) +--TS2 345 |REPLICATOR | |REPLICATOR | 346 +--------+--+ +--+--------+ 347 | | 348 +--+----------------+--+ 349 | | 350 | | 351 +----+ VXLAN/nvGRE/MPLSoGRE +----+ 352 | | IP Fabric | | 353 | | | | 354 NVE1 | +-----------+----------+ | NVE3 355 Hypervisor| TOR | NVE2 |Hypervisor 356 +---------+-+ +-----+-----+ +-+---------+ 357 | (EVI-1) | | (EVI-1) | | (EVI-1) | 358 | LEAF | | RNVE | | LEAF | 359 +--+-----+--+ +--+-----+--+ +--+-----+--+ 360 | | | | | | 361 VM11 VM12 TS3 TS4 VM31 VM32 363 Figure 1 Optimized-IR scenario 365 4.1. Non-selective AR-REPLICATOR procedures 367 An AR-REPLICATOR is defined as an NVE/PE capable of replicating 368 ingress BM (Broadcast and Multicast) traffic received on an overlay 369 tunnel to other overlay tunnels and local Attachment Circuits (ACs). 370 The AR-REPLICATOR signals its role in the control plane and 371 understands where the other roles (AR-LEAF nodes, RNVEs and other AR- 372 REPLICATORs) are located. A given AR-enabled EVI service may have 373 zero, one or more AR-REPLICATORs. In our example in figure 1, PE1 and 374 PE2 are defined as AR-REPLICATORs. The following considerations apply 375 to the AR-REPLICATOR role: 377 a) The AR-REPLICATOR role SHOULD be an administrative choice in any 378 NVE/PE that is part of an AR-enabled EVI. This administrative 379 option to enable AR-REPLICATOR capabilities MAY be implemented as 380 a system level option as opposed to as a per-MAC-VRF option. 382 b) An AR-REPLICATOR MUST advertise a Replicator-AR route and MAY 383 advertise a Regular-IR route. The AR-REPLICATOR MUST NOT generate 384 a Regular-IR route if it does not have local attachment circuits 385 (AC). If the Regular-IR route is advertised, the AR Type field MAY 386 be set to AR-REPLICATOR. 388 c) The Replicator-AR and Regular-IR routes will be generated 389 according to section 3. The AR-IP and IR-IP used by the 390 Replicator-AR will be different routable IP addresses. 392 d) When a node defined as AR-REPLICATOR receives a packet on an 393 overlay tunnel, it will do a tunnel destination IP lookup and 394 apply the following procedures: 396 o If the destination IP is the AR-REPLICATOR IR-IP Address the 397 node will process the packet normally as in [RFC7432]. 399 o If the destination IP is the AR-REPLICATOR AR-IP Address the 400 node MUST replicate the packet to local ACs and overlay 401 tunnels (excluding the overlay tunnel to the source of the 402 packet). When replicating to remote AR-REPLICATORs the tunnel 403 destination IP will be an IR-IP. That will be an indication 404 for the remote AR-REPLICATOR that it MUST NOT replicate to 405 overlay tunnels. The tunnel source IP used by the AR- 406 REPLICATOR MUST be its IR-IP. 408 4.2. Non-selective AR-LEAF procedures 410 AR-LEAF is defined as an NVE/PE that - given its poor replication 411 performance - sends all the BM traffic to an AR-REPLICATOR that can 412 replicate the traffic further on its behalf. It MAY signal its AR- 413 LEAF capability in the control plane and understands where the other 414 roles are located (AR-REPLICATOR and RNVEs). A given service can have 415 zero, one or more AR-LEAF nodes. Figure 1 shows NVE1 and NVE3 (both 416 residing in hypervisors) acting as AR-LEAF. The following 417 considerations apply to the AR-LEAF role: 419 a) The AR-LEAF role SHOULD be an administrative choice in any NVE/PE 420 that is part of an AR-enabled EVI. This administrative option to 421 enable AR-LEAF capabilities MAY be implemented as a system level 422 option as opposed to as per-MAC-VRF option. 424 b) In this non-selective AR solution, the AR-LEAF MUST advertise a 425 single Regular-IR inclusive multicast route as in [RFC7432]. The 426 AR-LEAF SHOULD set the AR Type field to AR-LEAF. Note that 427 although this flag does not make any difference for the egress 428 nodes when creating an EVPN destination to the the AR-LEAF, it is 429 RECOMMENDED the use of this flag for an easy operation and 430 troubleshooting of the EVI. 432 c) In a service where there are no AR-REPLICATORs, the AR-LEAF MUST 433 use regular ingress replication. This will happen when a new 434 update from the last former AR-REPLICATOR is received and contains 435 a non-REPLICATOR AR type, or when the AR-LEAF detects that the 436 last AR-REPLICATOR is down (next-hop tracking in the IGP or any 437 other detection mechanism). Ingress replication MUST use the 438 forwarding information given by the remote Regular-IR Inclusive 439 Multicast Routes as described in [RFC7432]. 441 d) In a service where there is one or more AR-REPLICATORs (based on 442 the received Replicator-AR routes for the EVI), the AR-LEAF can 443 locally select which AR-REPLICATOR it sends the BM traffic to: 445 o A single AR-REPLICATOR MAY be selected for all the BM packets 446 received on the AR-LEAF attachment circuits (ACs) for a given 447 EVI. This selection is a local decision and it does not have 448 to match other AR-LEAF's selection within the same EVI. 450 o An AR-LEAF MAY select more than one AR-REPLICATOR and do 451 either per-flow or per-EVI load balancing. 453 o In case of a failure on the selected AR-REPLICATOR, another 454 AR-REPLICATOR will be selected. 456 o When an AR-REPLICATOR is selected, the AR-LEAF MUST send all 457 the BM packets to that AR-REPLICATOR using the forwarding 458 information given by the Replicator-AR route for the chosen 459 AR-REPLICATOR, with tunnel type = 0x0A (AR tunnel). The 460 underlay destination IP address MUST be the AR-IP advertised 461 by the AR-REPLICATOR in the Replicator-AR route. 463 o AR-LEAF nodes SHALL send service-level BM control plane 464 packets following regular IR procedures. An example would be 465 IGMP, MLD or PIM multicast packets. The AR-REPLICATORs MUST 466 NOT replicate these control plane packets to other overlay 467 tunnels since they will use the regular IR-IP Address. 469 e) The use of an AR-REPLICATOR-activation-timer (in seconds) on the 470 AR-LEAF nodes is RECOMMENDED. Upon receiving a new Replicator-AR 471 route where the AR-REPLICATOR is selected, the AR-LEAF will run a 472 timer before programming the new AR-REPLICATOR. This will give the 473 AR-REPLICATOR some time to program the AR-LEAF nodes before the 474 AR-LEAF sends BM traffic. 476 4.3. RNVE procedures 478 RNVE (Regular Network Virtualization Edge node) is defined as an 479 NVE/PE without AR-REPLICATOR or AR-LEAF capabilities that does IR as 480 described in [RFC7432]. The RNVE does not signal any AR role and is 481 unaware of the AR-REPLICATOR/LEAF roles in the EVI. The RNVE will 482 ignore the Flags in the Regular-IR routes and will ignore the 483 Replicator-AR routes (due to an unknown tunnel type in the PTA) and 484 the Leaf-AD routes (due to the IP-address-specific route-target). 486 This role provides EVPN with the backwards compatibility required in 487 optimized-IR EVIs. Figure 1 shows NVE2 as RNVE. 489 4.4. Forwarding behavior in non-selective AR EVIs 491 In AR EVIs, BM (Broadcast and Multicast) traffic between two NVEs may 492 follow a different path than unicast traffic. This solution proposes 493 the replication of BM through the AR-REPLICATOR node, whereas 494 unknown/known unicast will be delivered directly from the source node 495 to the destination node without being replicated by any intermediate 496 node. Unknown unicast SHALL follow the same path as known unicast 497 traffic in order to avoid packet reordering for unicast applications 498 and simplify the control and data plane procedures. Section 4.4.1. 499 describes the expected forwarding behavior for BM traffic in nodes 500 acting as AR-REPLICATOR, AR-LEAF and RNVE. Section 4.4.2. describes 501 the forwarding behavior for unknown unicast traffic. 503 Note that known unicast forwarding is not impacted by this solution. 505 4.4.1. Broadcast and Multicast forwarding behavior 507 The expected behavior per role is described in this section. 509 4.4.1.1. Non-selective AR-REPLICATOR BM forwarding 511 The AR-REPLICATORs will build a flooding list composed of ACs and 512 overlay tunnels to remote nodes in the EVI. Some of those overlay 513 tunnels MAY be flagged as non-BM receivers based on the BM flag 514 received from the remote nodes in the EVI. 516 o When an AR-REPLICATOR receives a BM packet on an AC, it will 517 forward the BM packet to its flooding list (including local ACs and 518 remote NVE/PEs), skipping the non-BM overlay tunnels. 520 o When an AR-REPLICATOR receives a BM packet on an overlay tunnel, it 521 will check the destination IP of the underlay IP header and: 523 - If the destination IP matches its AR-IP, the AR-REPLICATOR will 524 forward the BM packet to its flooding list (ACs and overlay 525 tunnels) excluding the non-BM overlay tunnels. The AR-REPLICATOR 526 will do source squelching to ensure the traffic is not sent back 527 to the originating AR-LEAF. 529 - If the destination IP matches its IR-IP, the AR-REPLICATOR will 530 skip all the overlay tunnels from the flooding list, i.e. it 531 will only replicate to local ACs. This is the regular IR 532 behavior described in [RFC7432]. 534 4.4.1.2. Non-selective AR-LEAF BM forwarding 536 The AR-LEAF nodes will build two flood-lists: 538 1) Flood-list #1 - composed of ACs and an AR-REPLICATOR-set of 539 overlay tunnels. The AR-REPLICATOR-set is defined as one or more 540 overlay tunnels to the AR-IP Addresses of the remote AR- 541 REPLICATOR(s) in the EVI. The selection of more than one AR- 542 REPLICATOR is described in section 4.2. and it is a local AR- 543 LEAF decision. 545 2) Flood-list #2 - composed of ACs and overlay tunnels to the 546 remote IR-IP Addresses. 548 When an AR-LEAF receives a BM packet on an AC, it will check the 549 AR-REPLICATOR-set: 551 o If the AR-REPLICATOR-set is empty, the AR-LEAF will send the packet 552 to flood-list #2. 554 o If the AR-REPLICATOR-set is NOT empty, the AR-LEAF will send the 555 packet to flood-list #1, where only one of the overlay tunnels of 556 the AR-REPLICATOR-set is used. 558 When an AR-LEAF receives a BM packet on an overlay tunnel, will 559 forward the BM packet to its local ACs and never to an overlay 560 tunnel. This is the regular IR behavior described in [RFC7432]. 562 4.4.1.3. RNVE BM forwarding 564 The RNVE is completely unaware of the AR-REPLICATORs, AR-LEAF nodes 565 and BM/U flags (that information is ignored). Its forwarding behavior 566 is the regular IR behavior described in [RFC7432]. Any regular non-AR 567 node is fully compatible with the RNVE role described in this 568 document. 570 4.4.2. Unknown unicast forwarding behavior 572 The expected behavior is described in this section. 574 4.4.2.1. Non-selective AR-REPLICATOR/LEAF Unknown unicast forwarding 576 While the forwarding behavior in AR-REPLICATORs and AR-LEAF nodes is 577 different for BM traffic, as far as Unknown unicast traffic 578 forwarding is concerned, AR-LEAF nodes behave exactly in the same way 579 as AR-REPLICATORs do. 581 The AR-REPLICATOR/LEAF nodes will build a flood-list composed of ACs 582 and overlay tunnels to the IR-IP Addresses of the remote nodes in the 583 EVI. Some of those overlay tunnels MAY be flagged as non-U (Unknown 584 unicast) receivers based on the U flag received from the remote nodes 585 in the EVI. 587 o When an AR-REPLICATOR/LEAF receives an unknown packet on an AC, it 588 will forward the unknown packet to its flood-list, skipping the 589 non-U overlay tunnels. 591 o When an AR-REPLICATOR/LEAF receives an unknown packet on an overlay 592 tunnel will forward the unknown packet to its local ACs and never 593 to an overlay tunnel. This is the regular IR behavior described in 594 [RFC7432]. 596 4.4.2.2. RNVE Unknown unicast forwarding 598 As described for BM traffic, the RNVE is completely unaware of the 599 REPLICATORs, LEAF nodes and BM/U flags (that information is ignored). 600 Its forwarding behavior is the regular IR behavior described in 601 [RFC7432], also for Unknown unicast traffic. Any regular non-AR node 602 is fully compatible with the RNVE role described in this document. 604 5. Selective Assisted-Replication (AR) Solution Description 606 Figure 1 is also used to describe the selective AR solution, however 607 in this section we consider NVE2 as one more AR-LEAF for EVI-1. The 608 solution is called "selective" because a given AR-REPLICATOR MUST 609 replicate the BM traffic to only the AR-LEAF that requested the 610 replication (as opposed to all the AR-LEAF nodes) and MAY replicate 611 the BM traffic to the RNVEs. The same AR roles defined in section 4 612 are used here, however the procedures are slightly different. 614 The following sub-sections describe the differences in the procedures 615 of AR-REPLICATOR/LEAFs compared to the non-selective AR solution. 616 There is no change on the RNVEs. 618 5.1. Selective AR-REPLICATOR procedures 620 In our example in figure 1, PE1 and PE2 are defined as Selective AR- 621 REPLICATORs. The following considerations apply to the Selective AR- 622 REPLICATOR role: 624 a) The Selective AR-REPLICATOR capability SHOULD be an administrative 625 choice in any NVE/PE that is part of an AR-enabled EVI, as the AR 626 role itself. This administrative option MAY be implemented as a 627 system level option as opposed to as a per-MAC-VRF option. 629 b) Each AR-REPLICATOR will build a list of AR-REPLICATOR, AR-LEAF and 630 RNVE nodes (AR-LEAF nodes that sent only a regular-IR route are 631 accounted as RNVEs by the AR-REPLICATOR). In spite of the 632 'Selective' administrative option, an AR-REPLICATOR MUST NOT 633 behave as a Selective AR-REPLICATOR if at least one of the AR- 634 REPLICATORs has the L flag NOT set. If at least one AR-REPLICATOR 635 sends a Replicator-AR route with L=0 (in the EVI context), the 636 rest of the AR-REPLICATORs will fall back to non-selective AR 637 mode. 639 b) The Selective AR-REPLICATOR MUST follow the procedures described 640 in section 4.1, except for the following differences: 642 o The Replicator-AR route MUST include L=1 (Leaf Information 643 Required) in the Replicator-AR route. This flag is used by the 644 AR-REPLICATORs to advertise their 'selective' AR-REPLICATOR 645 capabilities. In addition, the AR-REPLICATOR auto-configures 646 its IP-address-specific import route-target as described in 647 section 3. 649 o The AR-REPLICATOR will build a 'selective' AR-LEAF-set with 650 the list of nodes that requested replication to its own AR-IP. 651 For instance, assuming NVE1 and NVE2 advertise a Leaf-AD route 652 with PE1's IP-address-specific route-target and NVE3 653 advertises a Leaf-AD route with PE2's IP-address-specific 654 route-target, PE1 MUST only add NVE1/NVE2 to its selective AR- 655 LEAF-set for EVI-1, and exclude NVE3. 657 o When a node defined and operating as Selective AR-REPLICATOR 658 receives a packet on an overlay tunnel, it will do a tunnel 659 destination IP lookup and if the destination IP is the AR- 660 REPLICATOR AR-IP Address, the node MUST replicate the packet 661 to: 663 + local ACs 664 + overlay tunnels in the Selective AR-LEAF-set (excluding the 665 overlay tunnel to the source AR-LEAF). 666 + overlay tunnels to the RNVEs if the tunnel source IP is the 667 IR-IP of an AR-LEAF (in any other case, the AR-REPLICATOR 668 MUST NOT replicate the BM traffic to remote RNVEs). In other 669 words, the first-hop selective AR-REPLICATOR will replicate 670 to all the RNVEs. 671 + overlay tunnels to the remote Selective AR-REPLICATORs if 672 the tunnel source IP is an IR-IP of its own AR-LEAF-set (in 673 any other case, the AR-REPLICATOR MUST NOT replicate the BM 674 traffic to remote AR-REPLICATORs), where the tunnel 675 destination IP is the AR-IP of the remote Selective AR- 676 REPLICATOR. The tunnel destination IP AR-IP will be an 677 indication for the remote Selective AR-REPLICATOR that the 678 packet needs further replication to its AR-LEAFs. 680 5.2. Selective AR-LEAF procedures 682 A Selective AR-LEAF chooses a single Selective AR-REPLICATOR per EVI 683 and: 685 o Sends all the EVI BM traffic to that AR-REPLICATOR and 686 o Expects to receive the BM traffic for a given EVI from the same AR- 687 REPLICATOR. 689 In the example of Figure 1, we consider NVE1/NVE2/NVE3 as Selective 690 AR-LEAFs. NVE1 selects PE1 as its Selective AR-REPLICATOR. If that is 691 so, NVE1 will send all its BM traffic for EVI-1 to PE1. If other AR- 692 LEAF/REPLICATORs send BM traffic, NVE1 will receive that traffic from 693 PE1. These are the differences in the behavior of a Selective AR-LEAF 694 compared to a non-selective AR-LEAF: 696 a) The AR-LEAF role selective capability SHOULD be an administrative 697 choice in any NVE/PE that is part of an AR-enabled EVI. This 698 administrative option to enable AR-LEAF capabilities MAY be 699 implemented as a system level option as opposed to as per-MAC-VRF 700 option. 702 b) The AR-LEAF MAY advertise a Regular-IR route if there are RNVEs in 703 the EVI. The Selective AR-LEAF MUST advertise a Leaf-AD route 704 after receiving a Replicator-AR route with L=1. It is recommended 705 that the Selective AR-LEAF waits for a timer t before sending the 706 Leaf-AD route, so that the AR-LEAF receives all the Replicator-AR 707 routes for the EVI. 709 c) In a service where there is more than one Selective AR-REPLICATORs 710 the Selective AR-LEAF MUST locally select a single Selective AR- 711 REPLICATOR for the EVI. Once selected: 713 o The Selective AR-LEAF will send a Leaf-AD route including the 714 Route-key and IP-address-specific route-target of the selected 715 AR-REPLICATOR. 717 o The Selective AR-LEAF will send all the BM packets received on 718 the attachment circuits (ACs) for a given EVI to that AR- 719 REPLICATOR. 721 o In case of a failure on the selected AR-REPLICATOR, another 722 AR-REPLICATOR will be selected and a new Leaf-AD update will 723 be issued for the new AR-REPLICATOR. This new route will 724 update the selective list in the new Selective AR-REPLICATOR. 725 In case of failure on the active Selective AR-REPLICATOR, it 726 is recommended for the Selective AR-LEAF to revert to IR 727 behavior for a timer t to speed up the convergence. When the 728 timer expires, the Selective AR-LEAF will resume its AR mode 729 with the new Selective AR-REPLICATOR. 731 All the AR-LEAFs in an EVI are expected to be configured as either 732 selective or non-selective. A mix of selective and non-selective AR- 733 LEAFs SHOULD NOT coexist in the same EVI. In case there is a non- 734 selective AR-LEAF, its BM traffic sent to a selective AR-REPLICATOR 735 will not be replicated to other AR-LEAFs that are not in its 736 Selective AR-LEAF-set. 738 5.3. Forwarding behavior in selective AR EVIs 740 This section describes the differences of the selective AR forwarding 741 mode compared to the non-selective mode. Compared to section 4.4, 742 there are no changes for the forwarding behavior in RNVEs or for 743 unknown unicast traffic. 745 5.3.1. Selective AR-REPLICATOR BM forwarding 747 The Selective AR-REPLICATORs will build two flood-lists: 749 1) Flood-list #1 - composed of ACs and overlay tunnels to the 750 remote nodes in the EVI, always using the IR-IPs in the tunnel 751 destination IP addresses. Some of those overlay tunnels MAY be 752 flagged as non-BM receivers based on the BM flag received from 753 the remote nodes in the EVI. 755 2) Flood-list #2 - composed of ACs, a Selective AR-LEAF-set and a 756 Selective AR-REPLICATOR-set, where: 758 o The Selective AR-LEAF-set is composed of the overlay tunnels 759 to the AR-LEAFs that advertise a Leaf-AD route for the local 760 AR-REPLICATOR. This set is updated with every Leaf-AD route 761 received/withdrawn from a new AR-LEAF. 763 o The Selective AR-REPLICATOR-set is composed of the overlay 764 tunnels to all the AR-REPLICATORs that send a Replicator-AR 765 route with L=1. The AR-IP addresses are used as tunnel 766 destination IP. 768 When a Selective AR-REPLICATOR receives a BM packet on an AC, it will 769 forward the BM packet to its flood-list #1, skipping the non-BM 770 overlay tunnels. 772 When a Selective AR-REPLICATOR receives a BM packet on an overlay 773 tunnel, it will check the destination and source IPs of the underlay 774 IP header and: 776 - If the destination IP matches its AR-IP and the source IP 777 matches an IP of its own Selective AR-LEAF-set, the AR- 778 REPLICATOR will forward the BM packet to its flood-list #2, as 779 long as the list of AR-REPLICATORs for the EVI matches the 780 Selective AR-REPLICATOR-set. If the Selective AR-REPLICATOR-set 781 does not match the list of AR-REPLICATORs, the node reverts back 782 to non-selective mode and flood-list #1 is used. 784 - If the destination IP matches its AR-IP and the source IP does 785 not match any IP of its Selective AR-LEAF-set, the AR-REPLICATOR 786 will forward the BM packet to flood-list #2 but skipping the AR- 787 REPLICATOR-set. 789 - If the destination IP matches its IR-IP, the AR-REPLICATOR will 790 use flood-list #1 but MUST skip all the overlay tunnels from the 791 flooding list, i.e. it will only replicate to local ACs. This is 792 the regular-IR behavior described in [RFC7432]. 794 In any case, non-BM overlay tunnels are excluded from flood-lists 795 and, also, source squelching is always done in order to ensure the 796 traffic is not sent back to the originating source. If the 797 encapsulation is MPLSoGRE (or MPLSoUDP) and the EVI label is not the 798 bottom of the stack, the AR-REPLICATOR MUST copy the rest of the 799 labels when forwarding them to the egress overlay tunnels. 801 5.3.2. Selective AR-LEAF BM forwarding 803 The Selective AR-LEAF nodes will build two flood-lists: 805 1) Flood-list #1 - composed of ACs and the overlay tunnel to the 806 selected AR-REPLICATOR (using the AR-IP as the tunnel 807 destination IP). 809 2) Flood-list #2 - composed of ACs and overlay tunnels to the 810 remote IR-IP Addresses. 812 When an AR-LEAF receives a BM packet on an AC, it will check if there 813 is any selected AR-REPLICATOR. If there is, flood-list #1 will be 814 used. Otherwise, flood-list #2 will. 816 When an AR-LEAF receives a BM packet on an overlay tunnel, will 817 forward the BM packet to its local ACs and never to an overlay 818 tunnel. This is the regular IR behavior described in [RFC7432]. 820 6. Pruned-Flood-Lists (PFL) 822 In addition to AR, the second optimization supported by this solution 823 is the ability for the all the EVI nodes to signal Pruned-Flood-Lists 824 (PFL). As described in section 3, an EVPN node can signal a given 825 value for the BM and U PFL flags in the IR Inclusive Multicast 826 Routes, where: 828 + BM= Broadcast and Multicast (BM) flag. BM=1 means "prune-me" from 829 the BM flood-list. BM=0 means regular behavior. 831 + U= Unknown flag. U=1 means "prune-me" from the Unknown flood-list. 832 U=0 means regular behavior. 834 The ability to signal these PFL flags is an administrative choice. 835 Upon receiving a non-zero PFL flag, a node MAY decide to honor the 836 PFL flag and remove the sender from the corresponding flood-list. A 837 given EVI node receiving BUM traffic on an overlay tunnel MUST 838 replicate the traffic normally, regardless of the signaled PFL 839 flags. 841 This optimization MAY be used along with the AR solution. 843 6.1. A PFL example 845 In order to illustrate the use of the solution described in this 846 document, we will assume that EVI-1 in figure 1 is optimized-IR 847 enabled and: 849 o PE1 and PE2 are administratively configured as AR-REPLICATORs, due 850 to their high-performance replication capabilities. PE1 and PE2 851 will send a Replicator-AR route with BM/U flags = 00. 853 o NVE1 and NVE3 are administratively configured as AR-LEAF nodes, due 854 to their low-performance software-based replication capabilities. 855 They will advertise a Regular-IR route with type AR-LEAF. Assuming 856 both NVEs advertise all the attached VMs in EVPN as soon as they 857 come up and don't have any VMs interested in multicast 858 applications, they will be configured to signal BM/U flags = 11 for 859 EVI-1. 861 o NVE2 is optimized-IR unaware; therefore it takes on the RNVE role 862 in EVI-1. 864 Based on the above assumptions the following forwarding behavior will 865 take place: 867 (1) Any BM packets sent from VM11 will be sent to VM12 and PE1. PE1 868 will forward further the BM packets to TS1, WAN link, PE2 and 869 NVE2, but not to NVE3. PE2 and NVE2 will replicate the BM packets 870 to their local ACs but we will avoid NVE3 having to replicate 871 unnecessarily those BM packets to VM31 and VM32. 873 (2) Any BM packets received on PE2 from the WAN will be sent to PE1 874 and NVE2, but not to NVE1 and NVE3, sparing the two hypervisors 875 from replicating unnecessarily to their local VMs. PE1 and NVE2 876 will replicate to their local ACs only. 878 (3) Any Unknown unicast packet sent from VM31 will be forwarded by 879 NVE3 to NVE2, PE1 and PE2 but not NVE1. The solution avoids the 880 unnecessary replication to NVE1, since the destination of the 881 unknown traffic cannot be at NVE1. 883 (4) Any Unknown unicast packet sent from TS1 will be forwarded by PE1 884 to the WAN link, PE2 and NVE2 but not to NVE1 and NVE3, since the 885 target of the unknown traffic cannot be at those NVEs. 887 7. AR Procedures for single-IP AR-REPLICATORS 889 The procedures explained in sections 4 (Non-selective AR) and 5 890 (Selective AR) assume that the AR-REPLICATOR can use two local 891 routable IP addresses to terminate and originate NVO tunnels, i.e. 892 IR-IP and AR-IP addresses. This is usually the case for PE-based AR- 893 REPLICATOR nodes. 895 In some cases, the AR-REPLICATOR node does not support more than one 896 IP address to terminate and originate NVO tunnels, i.e. the IR-IP and 897 AR-IP are the same IP addresses. This may be the case in some 898 software-based or low-end AR-REPLICATOR nodes. If this is the case, 899 the procedures in sections 4 and 5 must be modified in the following 900 way: 902 o The Replicator-AR routes generated by the AR-REPLICATOR use an AR- 903 IP that will match its IR-IP. In order to differentiate the data 904 plane packets that need to use IR from the packets that must use AR 905 forwarding mode, the Replicator-AR route must advertise a different 906 VNI/VSID than the one used by the Regular-IR route. For instance, 907 the AR-REPLICATOR will advertise AR-VNI along with the Replicator- 908 AR route and IR-VNI along with the Regular-IR route. Since both 909 routes have the same key, different RDs are needed for both routes. 911 o An AR-REPLICATOR will perform IR or AR forwarding mode for the 912 incoming Overlay packets based on an ingress VNI lookup, as opposed 913 to the tunnel IP DA lookup described in sections 4 and 5. Note 914 that, when replicating to remote AR-REPLICATOR nodes, the use of 915 the IR-VNI or AR-VNI advertised by the egress node will determine 916 the IR or AR forwarding mode at the subsequent AR-REPLICATOR. 918 The rest of the procedures will follow what is described in sections 919 4 and 5. 921 8. AR Procedures and EVPN All-Active Multi-homing Split-Horizon 923 8.1. Ethernet Segments on AR-LEAF nodes 925 If VXLAN or NVGRE are used, and if the Split-horizon is based on the 926 tunnel IP SA and "Local-Bias" as described in [RFC8365], the Split- 927 horizon check will not work if there is an Ethernet-Segment shared 928 between two AR-LEAF nodes, and the AR-REPLICATOR changes the tunnel 929 IP SA of the packets with its own AR-IP. 931 In order to be compatible with the IP SA split-horizon check, the AR- 932 REPLICATOR MAY keep the original received tunnel IP SA when 933 replicating packets to a remote AR-LEAF or RNVE. This will allow DF 934 (Designated Forwarder) AR-LEAF nodes to apply Split-horizon check 935 procedures for BM packets, before sending them to the local Ethernet- 936 Segment. Even if the AR-LEAF's IP SA is preserved when replicating to 937 AR-LEAFs or RNVEs, the AR-REPLICATOR MUST always use its IR-IP as IP 938 SA when replicating to other AR-REPLICATORs. 940 When EVPN is used for MPLS over GRE (or UDP), the ESI-label based 941 split-horizon procedure as in [RFC7432] will not work for multi-homed 942 Ethernet-Segments defined on AR-LEAF nodes. "Local-Bias" is 943 recommended in this case, as in the case of VXLAN or NVGRE explained 944 above. The "Local-Bias" and tunnel IP SA preservation mechanisms 945 provide the required split-horizon behavior in non-selective or 946 selective AR. 948 Note that if the AR-REPLICATOR implementation keeps the received 949 tunnel IP SA, the use of uRPF (unicast Reverse Path Forwarding) 950 checks in the IP fabric based on the tunnel IP SA MUST be disabled. 952 8.2. Ethernet Segments on AR-REPLICATOR nodes 954 Ethernet Segments associated to one or more AR-REPLICATOR nodes 955 SHOULD follow "Local-Bias" procedures for EVPN all-active multi- 956 homing, as follows: 958 o For BUM traffic received on a local AR-REPLICATOR's AC, "Local- 959 Bias" procedures as in [RFC8365] SHOULD be followed. 961 o For BUM traffic received on an AR-REPLICATOR overlay tunnel with 962 AR-IP as the IP DA, "Local-Bias" SHOULD also be followed. That is, 963 traffic received with AR-IP as IP DA will be treated as though it 964 had been received on a local AC that is part of the ES and will be 965 forwarded to all local ES, irrespective of their DF or NDF state. 967 o BUM traffic received on an AR-REPLICATOR overlay tunnel with IR-IP 968 as the IP DA, will follow regular [RFC8365] "Local-Bias" rules and 969 will not be forwarded to local ESes that are shared with the AR-LEF 970 or AR-REPLICATOR originating the traffic. 972 9. Benefits of the optimized-IR solution 974 A solution for the optimization of Ingress Replication in EVPN is 975 described in this document (optimized-IR). The solution brings the 976 following benefits: 978 o Optimizes the multicast forwarding in low-performance NVEs, by 979 relaying the replication to high-performance NVEs (AR-REPLICATORs) 980 and while preserving the packet ordering for unicast applications. 982 o Reduces the flooded traffic in NVO networks where some NVEs do not 983 need broadcast/multicast and/or unknown unicast traffic. 985 o It is fully compatible with existing EVPN implementations and EVPN 986 functions for NVO overlay tunnels. Optimized-IR NVEs and regular 987 NVEs can be even part of the same EVI. 989 o It does not require any PIM-based tree in the NVO core of the 990 network. 992 10. Conventions used in this document 994 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 995 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 996 "OPTIONAL" in this document are to be interpreted as described in BCP 997 14 [RFC2119] [RFC8174] when, and only when, they appear in all 998 capitals, as shown here. 1000 11. Security Considerations 1002 This section will be added in future versions. 1004 12. IANA Considerations 1006 IANA has allocated the following Border Gateway Protocol (BGP) 1007 Parameters: 1009 1) Allocation in the P-Multicast Service Interface Tunnel (PMSI 1010 Tunnel) Tunnel Types registry: 1012 Value Meaning Reference 1013 0x0A Assisted-Replication Tunnel [This document] 1015 2) Allocations in the P-Multicast Service Interface (PMSI) Tunnel 1016 Attribute Flags registry: 1018 Value Name Reference 1019 3-4 Assisted-Replication Type (T) [This document] 1020 5 Broadcast and Multicast (BM) [This document] 1021 6 Unknown (U) [This document] 1023 13. Terminology 1025 AC: Attachment Circuit 1027 Regular-IR: Refers to Regular Ingress Replication, where the source 1028 NVE/PE sends a copy to each remote NVE/PE part of the EVI. 1030 AR-IP: IP address owned by the AR-REPLICATOR and used to 1031 differentiate the ingress traffic that must follow the AR 1032 procedures. 1034 IR-IP: IP address used for Ingress Replication as in [RFC7432]. 1036 AR-VNI: VNI advertised by the AR-REPLICATOR along with the 1037 Replicator-AR route. It is used to identify the ingress 1038 packets that must follow AR procedures ONLY in the Single-IP 1039 AR-REPLICATOR case. 1041 IR-VNI: VNI advertised along with the RT-3 for IR. 1043 AR forwarding mode: for an AR-LEAF, it means sending an AC BM packet 1044 to a single AR-REPLICATOR with tunnel destination IP AR-IP. 1045 For an AR-REPLICATOR, it means sending a BM packet to a 1046 selective number or all the overlay tunnels when the packet 1047 was previously received from an overlay tunnel. 1049 IR forwarding mode: it refers to the Ingress Replication behavior 1050 explained in [RFC7432]. It means sending an AC BM packet copy 1051 to each remote PE/NVE in the EVI and sending an overlay BM 1052 packet only to the ACs and not other overlay tunnels. 1054 PTA: PMSI Tunnel Attribute 1056 RT-3: EVPN Route Type 3, Inclusive Multicast Ethernet Tag route 1058 RT-11: EVPN Route Type 11, Leaf Auto-Discovery (AD) route 1060 14. References 1062 14.1 Normative References 1064 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1065 Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1066 1997, . 1068 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1069 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, 1070 . 1072 [RFC6514] Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP 1073 Encodings and Procedures for Multicast in MPLS/BGP IP VPNs", 1074 RFC 6514, DOI 10.17487/RFC6514, February 2012, . 1077 [RFC7432] Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A., 1078 Uttaro, J., Drake, J., and W. Henderickx, "BGP MPLS-Based Ethernet 1079 VPN", RFC 7432, DOI 10.17487/RFC7432, February 2015, 1080 . 1082 [RFC7902] Rosen, E. and T. Morin, "Registry and Extensions for P- 1083 Multicast Service Interface Tunnel Attribute Flags", RFC 7902, DOI 1084 10.17487/RFC7902, June 2016, . 1087 [EVPN-BUM] Zhang et al., "Updates on EVPN BUM Procedures", draft- 1088 ietf-bess-evpn-bum-procedure-updates-04.txt, work in progress, June 1089 2018. 1091 14.2 Informative References 1093 [RFC8365] Sajassi et al., "A Network Virtualization Overlay Solution 1094 Using Ethernet VPN (EVPN)", RFC 8365, March, 2018. 1096 15.0 Contributors 1098 In addition to the names in the front page, the following co-authors 1099 also contributed to this document: 1101 Wim Henderickx 1102 Nokia 1104 Kiran Nagaraj 1105 Nokia 1107 Ravi Shekhar 1108 Juniper Networks 1110 Nischal Sheth 1111 Juniper Networks 1113 Aldrin Isaac 1114 Juniper 1116 Mudassir Tufail 1117 Citibank 1119 16. Acknowledgments 1121 The authors would like to thank Neil Hart, David Motz, Dai Truong, 1122 Thomas Morin, Jeffrey Zhang and Shankar Murthy for their valuable 1123 feedback and contributions. 1125 17. Authors' Addresses 1127 Jorge Rabadan (Editor) 1128 Nokia 1129 777 E. Middlefield Road 1130 Mountain View, CA 94043 USA 1131 Email: jorge.rabadan@nokia.com 1133 Senthil Sathappan 1134 Nokia 1135 Email: senthil.sathappan@nokia.com 1136 Mukul Katiyar 1137 Versa Networks 1138 Email: mukul@versa-networks.com 1140 Wen Lin 1141 Juniper Networks 1142 Email: wlin@juniper.net 1144 Ali Sajassi 1145 Cisco 1146 Email: sajassi@cisco.com