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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-07) exists of draft-ietf-bess-mvpn-extranet-02 Summary: 0 errors (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group Z. Zhang 3 Internet-Draft Y. Rekhter 4 Intended status: Standards Track Juniper Networks 5 Expires: April 18, 2016 A. Dolganow 6 Alcatel-Lucent 7 October 16, 2015 9 Simulating "Partial Mesh of MP2MP P-Tunnels" with Ingress Replication 10 draft-ietf-bess-mvpn-bidir-ingress-replication-04.txt 12 Abstract 14 RFC 6513 (Multicast in MPLS/BGP IP VPNs) describes a method to 15 support bidirectional customer multicast flows using a partial mesh 16 of Multipoint-to-Multipoint (MP2MP) tunnels. This document specifies 17 how a partial mesh of MP2MP tunnels can be simulated using Ingress 18 Replication. This solution enables a Service Provider to use Ingress 19 Replication to offer transparent bidirectional multicast service to 20 its VPN customers. 22 Status of this Memo 24 This Internet-Draft is submitted in full conformance with the 25 provisions of BCP 78 and BCP 79. 27 Internet-Drafts are working documents of the Internet Engineering 28 Task Force (IETF). Note that other groups may also distribute 29 working documents as Internet-Drafts. The list of current Internet- 30 Drafts is at http://datatracker.ietf.org/drafts/current/. 32 Internet-Drafts are draft documents valid for a maximum of six months 33 and may be updated, replaced, or obsoleted by other documents at any 34 time. It is inappropriate to use Internet-Drafts as reference 35 material or to cite them other than as "work in progress." 37 This Internet-Draft will expire on April 18, 2016. 39 Copyright Notice 41 Copyright (c) 2015 IETF Trust and the persons identified as the 42 document authors. All rights reserved. 44 This document is subject to BCP 78 and the IETF Trust's Legal 45 Provisions Relating to IETF Documents 46 (http://trustee.ietf.org/license-info) in effect on the date of 47 publication of this document. Please review these documents 48 carefully, as they describe your rights and restrictions with respect 49 to this document. Code Components extracted from this document must 50 include Simplified BSD License text as described in Section 4.e of 51 the Trust Legal Provisions and are provided without warranty as 52 described in the Simplified BSD License. 54 Table of Contents 56 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 57 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 58 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4 59 3. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 5 60 3.1. Control State . . . . . . . . . . . . . . . . . . . . . . 5 61 3.2. Forwarding State . . . . . . . . . . . . . . . . . . . . . 7 62 4. Security Considerations . . . . . . . . . . . . . . . . . . . 8 63 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 64 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10 65 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 66 7.1. Normative References . . . . . . . . . . . . . . . . . . . 11 67 7.2. Informative References . . . . . . . . . . . . . . . . . . 11 68 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12 70 1. Introduction 72 Section 11.2 of RFC 6513, "Partitioned Sets of PEs", describes two 73 methods of carrying BIDIR-PIM [RFC5015] C-flow traffic over a 74 provider core without using the core as the Rendezvous Point Link 75 (RPL) or requiring Designated Forwarder election. 77 With these two methods, all PEs of a particular VPN are separated 78 into partitions, with each partition being all the PEs that elect the 79 same PE as the Upstream PE with respect to the C-RPA. A PE must 80 discard bidirectional C-flow traffic from PEs that are not in the 81 same partition as the PE itself. 83 In particular, Section 11.2.3 of RFC 6513, "Partial Mesh of MP2MP 84 P-Tunnels", guarantees the above discard behavior without using an 85 extra PE Distinguisher label by having all PEs in the same partition 86 join a single MP2MP tunnel dedicated to that partition and use it to 87 transmit traffic. All traffic arriving on the tunnel will be from 88 PEs in the same partition, so it will be always accepted. 90 RFC 6514 specifies BGP encodings and procedures used to implement 91 MVPN as specified in RFC 6513, while the details related to MP2MP 92 tunnels are specified in [RFC7582]. 94 RFC 7582 assumes that an MP2MP P-tunnel is realized either via Bidir- 95 PIM [RFC5015], or via MP2MP mLDP [RFC6388]. Each of them would 96 require signaling and state not just on PEs, but on the P routers as 97 well. This document describes how the MP2MP tunnel can be simulated 98 with a mesh of P2MP tunnels, each of which is instantiated by Ingress 99 Replication (IR) [RFC6513, RFC6514]. Different from the procedures 100 in RFC 6514 that are used to set up the mesh of Ingress Replication 101 tunnels, the procedures in this document do not require each PE on 102 the MP2MP tunnel to send an S-PMSI A-D route for the P2MP tunnel that 103 the PE is the root for, nor does it require each PE to send a Leaf 104 A-D route to the root of each P2MP tunnel in the mesh. 106 With the use of Ingress Replication, this scheme has both the 107 advantages and the disadvantages of Ingress Replication in general. 109 1.1. Terminology 111 This document uses terminology from [RFC5015], [RFC6513], [RFC6514], 112 and [RFC7582]. 114 2. Requirements Language 116 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 117 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 118 document are to be interpreted as described in [RFC2119]. 120 3. Operation 122 In following sections, the originator of an S-PMSI A-D route or Leaf 123 A-D route is determined from the "originating router's IP address" 124 field of the corresponding route. 126 3.1. Control State 128 If a PE, say PEx, is connected to a site of a given VPN, and PEx's 129 next hop interface to some C-RPA is a VRF interface, then PEx MUST 130 advertises a (C-*,C-*-BIDIR) S-PMSI A-D route, regardless of whether 131 it has any local Bidir-PIM join states corresponding to the C-RPA 132 learned from its CEs. It MAY also advertise one or more (C-*,C-G- 133 BIDIR) S-PMSI A-D route, if selective distribution trees are needed 134 for those C-G-BIDIR groups, and the corresponding C-RPA is in the 135 site that the PEx connects to. For example, the (C-*,C-G-BIDIR) 136 S-PMSI A-D routes could be triggered when the (C-*, C-G-BIDIR) 137 traffic rate goes above a threshold (this may require measuring the 138 traffic in both directions, due to the nature of Bidir-PIM), and fan- 139 out could also be taken into account. 141 The S-PMSI A-D routes include a PMSI Tunnel Attribute (PTA) with 142 tunnel type set to Ingress Replication, with Leaf Information 143 Required flag set, with a downstream allocated MPLS label that other 144 PEs in the same partition MUST use when sending relevant C-bidir 145 flows to this PE, and with the Tunnel Identifier field in the PTA set 146 to a routable address of the originator. This specification does not 147 prevent sharing of labels between P-tunnels, such as a label being 148 shared by a (C-*,C-*- BIDIR) and a (C-*,C-G-BIDIR) S-PMSI A-D route 149 originated by a given PE (note that other specs put constraints on 150 how that can be done, e.g. [I-D.ietf-bess-mvpn-extranet]). 152 If some other PE, PEy, receives and imports into one of its VRFs any 153 (C-*, C-*-BIDIR) S-PMSI A-D route whose PTA specifies an IR P-tunnel, 154 and the VRF has any local Bidir-PIM join state that PEy has received 155 from its CEs, and if PEy chooses PEx as its Upstream PE with respect 156 to the C-RPA for those states, PEy MUST advertise a Leaf A-D route in 157 response. Or, if PEy has received and imported into one of its VRFs 158 a (C-*,C-*-BIDIR) S-PMSI A-D route from PEx before, then upon 159 receiving in the VRF any local Bidir-PIM join state from its CEs with 160 PEx being the Upstream PE for those states' C-RPA, PEy MUST advertise 161 a Leaf A-D route. 163 The encoding of the Leaf A-D route is as specified in RFC 6514, 164 except that the Route Targets are set to the same value as in the 165 corresponding S-PMSI A-D route so that the Leaf A-D route will be 166 imported by all VRFs that import the corresponding S-PMSI A-D route. 167 This is irrespective of whether the originator of the S-PMSI A-D 168 route is the Upstream PE or not from a receiving PE's perspective. 169 The label in the PTA of the Leaf A-D route originated by PEy MUST be 170 allocated specifically for PEx, so that when traffic arrives with 171 that label, the traffic can associated with the partition 172 (represented by the PEx). This specification does not prevent 173 sharing of labels between P-tunnels, such as a label being shared by 174 a (C-*,C-*- BIDIR) and a (C-*,C-G-BIDIR) Leaf A-D route originated by 175 a given PE (note that other specs put constraints on how that can be 176 done, e.g. [I-D.ietf-bess-mvpn-extranet]). 178 Note that RFC 6514 requires a PE/ASBR take no action with regard to a 179 Leaf A-D route unless that Leaf A-D route carries an IP Address 180 Specific RT identifying the PE/ASBR. This document removes that 181 requirement when the route key of a Leaf A-D route identifies a 182 (C-*,C-*-BIDIR) or a (C-*,C-G-BIDIR) S-PMSI. 184 To speed up convergence (so that PEy starts receiving traffic from 185 its new Upstream PE immediately instead of waiting until the new Leaf 186 A-D route corresponding to the new Upstream PE is received by sending 187 PEs), PEy MAY advertise a Leaf A-D route even if does not choose PEx 188 as its Upstream PE with respect to the C-RPA. With that, it will 189 receive traffic from all PEs, but some will arrive with the label 190 corresponding to its choice of Upstream PE while some will arrive 191 with a different label, and the traffic in the latter case will be 192 discarded. 194 Similar to the (C-*,C-*-BIDIR) case, if PEy receives and imports into 195 one of its VRFs any (C-*,C-G-BIDIR) S-PMSI A-D route whose PTA 196 specifies an IR P-tunnel, and PEy chooses PEx as its Upstream PE with 197 respect to the C-RPA, and it has corresponding local (C-*,C-G-BIDIR) 198 join state that it has received from its CEs in the VRF, PEy MUST 199 advertise a Leaf A-D route in response. Or, if PEy has received and 200 imported into one of its VRFs a (C-*,C-G-BIDIR) S-PMSI A-D route 201 before, then upon receiving its local (C-*,C-G-BIDIR) join state from 202 its CEs in the VRF, it MUST advertise a Leaf A-D route. 204 The encoding of the Leaf A-D route is the similar to the (C-*,C-*- 205 BIDIR) case. Also similarly, PEy MAY advertise a Leaf A-D route even 206 if it does not choose PEx as its Upstream PE with respect to the 207 C-RPA. 209 Whenever the (C-*,C-*-BIDIR) or (C-*,C-G-BIDIR) S-PMSI A-D route is 210 withdrawn, or if PEy no longer chooses the originator PEx as its 211 Upstream PE with respect to C-RPA and PEy only advertises Leaf A-D 212 routes in response to its Upstream PE's S-PMSI A-D route, or if 213 relevant local join state is pruned, PEy MUST withdraw the 214 corresponding Leaf A-D route. 216 3.2. Forwarding State 218 The following specification regarding forwarding state matches the 219 "When an S-PMSI is a 'Match for Transmission'" and "When an S-PMSI is 220 a 'Match for Reception'" rules for "Flat Partitioning" method in 221 [RFC7582], except that the rules about (C-*,C-*) are not applicable, 222 because this document requires that (C-*,C-*-BIDIR) S-PMSI A-D routes 223 are always originated for a VPN that supports C-Bidir flows. 225 For the (C-*,C-G-BIDIR) S-PMSI A-D route that a PEy receives and 226 imports into one of its VRFs from its Upstream PE with respect to the 227 C-RPA, or if PEy itself advertises the S-PMSI A-D route in the VRF, 228 PEy maintains a (C-*,C-G-BIDR) forwarding state in the VRF, with the 229 Ingress Replication provider tunnel leaves being the originators of 230 the S-PMSI A-D route and all relevant Leaf-A-D routes. The relevant 231 Leaf A-D routes are the routes whose Route Key field contains the 232 same information as the MCAST-VPN NLRI of the (C-*, C-G-BIDIR) S-PMSI 233 A-D route advertised by the Upstream PE. 235 For the (C-*,C-*-BIDIR) S-PMSI A-D route that a PEy receives and 236 imports into one of its VRFs from its Upstream PE with respect to a 237 C-RPA, or if PEy itself advertises the S-PMSI A-D route in the VRF, 238 it maintains appropriate forwarding states in the VRF for the ranges 239 of bidirectional groups for which the C-RPA is responsible. The 240 provider tunnel leaves are the originators of the S-PMSI A-D route 241 and all relevant Leaf-A-D routes. The relevant Leaf A-D routes are 242 the routes whose Route Key field contains the same information as the 243 MCAST-VPN NLRI of the (C-*, C-*-BIDIR) S-PMSI A-D route advertised by 244 the Upstream PE. This is for the so-called "Sender Only Branches" 245 where a router only has data to send upstream towards C-RPA but no 246 explicit join state for a particular bidirectional group. Note that 247 the traffic must be sent to all PEs (not just the Upstream PE) in the 248 partition, because they may have specific (C-*,C-G-BIDIR) join states 249 that this PEy is not aware of, while there is no corresponding 250 (C-*,C-G-BIDIR) S-PMSI A-D and Leaf A-D routes. 252 For a (C-*,C-G-BIDIR) join state that a PEy has received from its CEs 253 in a VRF, if there is no corresponding (C-*,C-G-BIDIR) S-PMSI A-D 254 route from its Upstream PE in the VRF, PEy maintains a corresponding 255 forwarding state in the VRF, with the provider tunnel leaves being 256 the originators of the (C-*,C-*-BIDIR) S-PMSI A-D route and all 257 relevant Leaf-A-D routes (same as the above Sender Only Branch case). 258 The relevant Leaf A-D routes are the routes whose Route Key field 259 contains the same information as the MCAST-VPN NLRI of the (C-*, 260 C-*-BIDIR) S-PMSI A-D route originated by the Upstream PE. If there 261 is no (C-*,C-*-BIDIR) S-PMSI A-D route from its Upstream PE either, 262 then the provider tunnel has an empty set of leaves and PEy does not 263 forward relevant traffic across the provider network. 265 4. Security Considerations 267 This document raises no new security issues. Security considerations 268 for the base protocol are covered in RFC6513 and RFC6514. 270 5. IANA Considerations 272 This document has no IANA considerations. 274 This section should be removed by the RFC Editor prior to final 275 publication. 277 6. Acknowledgements 279 We would like to thank Eric Rosen for his comments, and suggestions 280 of some texts used in the document. 282 7. References 284 7.1. Normative References 286 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 287 Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/ 288 RFC2119, March 1997, 289 . 291 [RFC6513] Rosen, E., Ed. and R. Aggarwal, Ed., "Multicast in MPLS/ 292 BGP IP VPNs", RFC 6513, DOI 10.17487/RFC6513, 293 February 2012, . 295 [RFC6514] Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP 296 Encodings and Procedures for Multicast in MPLS/BGP IP 297 VPNs", RFC 6514, DOI 10.17487/RFC6514, February 2012, 298 . 300 [RFC7582] Rosen, E., Wijnands, IJ., Cai, Y., and A. Boers, 301 "Multicast Virtual Private Network (MVPN): Using 302 Bidirectional P-Tunnels", RFC 7582, DOI 10.17487/RFC7582, 303 July 2015, . 305 7.2. Informative References 307 [RFC5015] Handley, M., Kouvelas, I., Speakman, T., and L. Vicisano, 308 "Bidirectional Protocol Independent Multicast (BIDIR- 309 PIM)", RFC 5015, DOI 10.17487/RFC5015, October 2007, 310 . 312 [RFC6388] Wijnands, IJ., Ed., Minei, I., Ed., Kompella, K., and B. 313 Thomas, "Label Distribution Protocol Extensions for Point- 314 to-Multipoint and Multipoint-to-Multipoint Label Switched 315 Paths", RFC 6388, DOI 10.17487/RFC6388, November 2011, 316 . 318 [I-D.ietf-bess-mvpn-extranet] 319 Rekhter, Y., Rosen, E., Aggarwal, R., Cai, Y., and T. 320 Morin, "Extranet Multicast in BGP/IP MPLS VPNs", 321 draft-ietf-bess-mvpn-extranet-02 (work in progress), 322 May 2015. 324 Authors' Addresses 326 Zhaohui Zhang 327 Juniper Networks 328 10 Technology Park Dr. 329 Westford, MA 01886 330 US 332 Email: zzhang@juniper.net 334 Yakov Rekhter 335 Juniper Networks 337 Andrew Dolganow 338 Alcatel-Lucent 339 600 March Rd. 340 Ottawa, ON K2K 2E6 341 CANADA 343 Email: andrew.dolganow@alcatel-lucent.com