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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 L2VPN Working Group Dave Allan, Jeff Tantsura 2 Internet Draft Ericsson 3 Intended status: Standards Track Don Fedyk 4 Expires: April 2015 HP 5 Ali Sajassi 6 Cisco 8 October 2014 10 Shortest Path Bridging, MAC mode Support over EVPN 11 draft-ietf-l2vpn-spbm-evpn-02 13 Abstract 15 This document describes how Ethernet Shortest Path Bridging MAC mode 16 (802.1aq) can be combined with EVPN in a way that interworks with 17 PBB-PEs as described in the PBB-EVPN solution. This is achieved via 18 operational isolation of each Ethernet network subtending an EVPN 19 core while supporting full interworking between the different 20 variations of Ethernet networks. 22 Status of this Memo 24 This Internet-Draft is submitted to IETF in full conformance 25 with the provisions of BCP 78 and BCP 79. 27 Internet-Drafts are working documents of the Internet 28 Engineering Task Force (IETF), its areas, and its working 29 groups. Note that other groups may also distribute working 30 documents as Internet-Drafts. 32 Internet-Drafts are draft documents valid for a maximum of six 33 months and may be updated, replaced, or obsoleted by other 34 documents at any time. It is inappropriate to use Internet- 35 Drafts as reference material or to cite them other than as "work 36 in progress". 38 The list of current Internet-Drafts can be accessed at 39 http://www.ietf.org/ietf/1id-abstracts.txt. 41 The list of Internet-Draft Shadow Directories can be accessed at 42 http://www.ietf.org/shadow.html. 44 This Internet-Draft will expire on October 2014. 46 Copyright and License Notice 47 Copyright (c) 2014 IETF Trust and the persons identified as the 48 document authors. All rights reserved. 50 This document is subject to BCP 78 and the IETF Trust's Legal 51 Provisions Relating to IETF Documents 52 (http://trustee.ietf.org/license-info) in effect on the date of 53 publication of this document. Please review these documents 54 carefully, as they describe your rights and restrictions with 55 respect to this document. Code Components extracted from this 56 document must include Simplified BSD License text as described 57 in Section 4.e of the Trust Legal Provisions and are provided 58 without warranty as described in the Simplified BSD License. 60 Table of Contents 62 1. Introduction...................................................3 63 1.1. Authors......................................................3 64 1.2. Requirements Language........................................3 65 2. Conventions used in this document..............................3 66 2.1. Terminology..................................................3 67 3. Changes since previous version.................................4 68 4. Solution Overview..............................................4 69 5. Elements of Procedure..........................................5 70 5.1. PE Configuration.............................................5 71 5.2. DF Election..................................................6 72 5.3. Control plane interworking ISIS-SPB to EVPN..................6 73 5.4. Control plane interworking EVPN to ISIS-SPB..................7 74 5.5. Data plane Interworking 802.1aq SPBM island or PBB-PE to 75 EVPN..............................................................8 76 5.6. Data plane Interworking EVPN to 802.1aq SPBM island..........8 77 5.7. Data plane interworking EVPN to 802.1ah PBB-PE...............8 78 5.8. Multicast Support............................................8 79 6. Other Aspects..................................................8 80 6.1. Flow Ordering................................................8 81 6.2. Transit......................................................8 82 7. Acknowledgements...............................................9 83 8. Security Considerations........................................9 84 9. IANA Considerations............................................9 85 10. References....................................................9 86 10.1. Normative References........................................9 87 10.2. Informative References......................................9 88 11. Authors' Addresses...........................................10 90 1. Introduction 92 This document describes how Ethernet Shortest Path Bridging MAC mode 93 (802.1aq) along with PBB-PEs and PBBNs (802.1ah) can be supported by 94 EVPN such that each island is operationally isolated while providing 95 full L2 connectivity between them. Each island can use its own 96 control plane instance and multi-pathing design, be it multiple ECT 97 sets, or multiple spanning trees. 99 The intention is to permit both past, current and emerging future 100 versions of Ethernet to be seamlessly integrated to permit large 101 scale, geographically diverse numbers of Ethernet end systems to be 102 fully supported with EVPN as the unifying agent. 104 1.1. Authors 106 David Allan, Jeff Tantsura, Don Fedyk, Ali Sajassi 108 1.2. Requirements Language 110 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 111 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 112 document are to be interpreted as described in RFC2119 [RFC2119]. 114 2. Conventions used in this document 116 2.1. Terminology 118 BEB: Backbone Edge Bridge 119 B-MAC: Backbone MAC Address 120 B-VID: Backbone VLAN ID 121 CE: Customer Edge 122 DF: Designated Forwarder 123 ESI: Ethernet Segment Identifier 124 EVPN: Ethernet VPN 125 IB-BEB: A BEB that has both an I-component (customer layer VLAN 126 aware bridge) and a B-component (backbone layer VLAN aware 127 bridge) 128 ISIS-SPB: IS-IS as extended for SPB 129 I-SID: I-Component Service ID 130 NLRI: Network Layer Reachability Information 131 PBBN: Provider Backbone Bridged Network 132 PBB-PE: Co located 802.1ah BEB and EVPN PE 133 PE: provider edge 134 SPB: Shortest path bridging 135 SPBM: Shortest path bridging MAC mode 136 SPBM-PE: Co-located 802.1aq SPBM<->EVPN interworking function and 137 EVPN PE 139 3. Changes since previous version 141 1) References corrected/updated. 143 2) Reference to draft-allan-mldp-evpn removed. 145 4. Solution Overview 147 The EVPN solution for 802.1aq SPBM incorporates control plane 148 interworking in the PE to map ISIS-SPB [RFC6329] information elements 149 into the EVPN NLRI information and vice versa. This requires each PE to 150 act both as an EVPN BGP speaker and as an ISIS-SPB edge node. Associated 151 with this are procedures for configuring the forwarding operations of 152 the PE such that an arbitrary number of EVPN subtending SPBM islands may 153 be interconnected without any topological or multipathing dependencies. 154 This model also permits PBB-PEs as defined in 0to be seamlessly 155 communicate with the SPB islands. 157 +--------------+ 158 | | 159 | | 160 +-----+ +----+ | | +----+ +---+ 161 | |-----|SPBM| | | |PBB |---|CE2| 162 |SPBM | |PE1 | | IP/MPLS | |PE1 | +---+ 163 +---+ |NTWK1| +----+ | Network | +----+ 164 |CE1|-| | | | 165 +---+ | | +----+ | | 166 | |-----|SPBM| | | +----+ +-----+ 167 +-----+ |PE2 | | | |SPBM| |SPBM | +---+ 168 +----+ | | |PE3 |---|NTWK2|-|CE3| 169 +--------------+ +----+ +-----+ +---+ 171 Figure 1: PBB and SPBM EVPN Network 173 Each EVPN is identified by a route target. The route target identifies 174 the set of SPBM islands and PBB-PEs that are allowed to communicate. 175 Each SPBM island is administered to have an associated Ethernet Segment 176 ID (ESI) associated with it. This manifests itself as a set of Ethernet 177 segments, where each ESI is unique within the route target. 178 BGP acts as a common repository of the I-SID attachment points for the 179 set of subtending PEs/SPBM islands. This is in the form of B-MAC 180 address/I-SID/Tx-Rx-attribute tuples. BGP filters leaking I-SID 181 information into each SPBM island on the basis of locally registered 182 interest. If an SPBM island has no BEBs registering interest in an I- 183 SID, information about that I-SID from other SPBM islands, PBB-PEs or 184 PBBNs will not be leaked into the local ISIS-SPB routing system. 185 For each B-VID in an SPBM island, a single SPBM-PE is elected the 186 designated forwarder for the B-VID. An SPBM-PE may be a DF for more than 187 one B-VID. This is described further in section 5.2. The SPBM-PE 188 originates IS-IS advertisements as if it were an IB-BEB that proxies for 189 the other SPBM islands and PBB PEs in the EVPN defined by the route 190 target, but the PE typically will not actually host any I-components. 191 An SPBM-PE that is a DF for a B-VID strips the B-VID tag information 192 from frames relayed towards the EVPN. The DF also inserts the 193 appropriate B-VID tag information into frames relayed towards the SPBM 194 island on the basis of the local I-SID/B-VID bindings advertised in 195 ISIS-SPB. 197 5. Elements of Procedure 199 5.1. PE Configuration 201 At SPBM island commissioning a PE is configured with: 203 1) The route target for the service instance. Where a route target 204 is defined as identifying the set of SPBM islands, PBBNs and PBB- 205 PEs to be interconnected by the EVPN. 207 2) The unique ESI for the SPBM island. Mechanisms for deriving a 208 unique ESI for the SPBM island are for further study. 210 And the following is configured as part of commissioning an ISIS-SPB 211 node: 213 1) A Shortest Path Source ID (SPSourceID) used for algorithmic 214 construction of multicast DA addresses. Note this is required for 215 SPBM BEBs independent of the EVPN operation. 217 2) The set of VLANs (identified by B-VIDs) used in the SPBM island 218 and multi-pathing algorithm IDs to use. The set of B-VIDs and 219 multi-pathing algorithms used may be different in different 220 domains and the B-VID itself is removed for frames carried over 221 the IP/MPLS network. 223 A type-1 Route Distinguisher for the node can be auto-derived. This 224 will be described in a future version of the document. 226 5.2. DF Election 228 PEs self appoint in the role of DF for a B-VID for a given SPBM 229 island. The procedure used is as per section 8.5 of [EVPN] 230 "Designated Forwarder election". 231 A PE that assumes the role of DF for a given DF is responsible for 232 originating specific information into BGP from ISIS-SPB and vice 233 versa. A PE that ceases to perform the role of DF for a given B-VID 234 is responsible for withdrawing the associated information from BGP 235 and ISIS-SPB respectively. The actual information exchanged is 236 outlined in the following sections. 238 5.3. Control plane interworking ISIS-SPB to EVPN 240 When a PE receives an SPBM service identifier and unicast address 241 sub-TLV as part of an ISIS-SPB MT capability TLV it checks if it is 242 the DF for the B-VID in the sub-TLV. 244 If it is the DF, and there is new or changed information then a MAC 245 advertisement route NLRI is created for each new I-SID in the sub- 246 TLV. 248 - the Route Distinguisher is set to that of the PE. 250 - the ESI is that of the SPBM island. 252 - the Ethernet tag ID contains the I-SID (including the Tx/Rx 253 attributes). The encoding of I-SID information is as per figure 2. 255 0 1 2 3 256 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 258 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 259 |T|R| Reserved | I-SID | 260 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 262 Figure 2: I-SID encoding in the Ethernet tag-ID field 264 - the MAC address is copied from the sub-TLV 266 - an locally assigned MPLS label 268 Similarly in the scenario where a PE became elected DF for a B-VID in 269 an operating network, the IS-IS database would be processed in order 270 to construct the NLRI information associated with the new role of the 271 PE. 273 If the BGP database has NLRI information for the I-SID, and this is 274 the first instance of registration of interest in the I-SID from the 275 SPB island, the NLRI information with that tag is processed to 276 construct an updated set of SPBM service identifier and unicast 277 address sub-TLVs to be advertised by the PE. 279 The ISIS-SPB information is also used to keep current a local table 280 indexed by I-SID to indicate the associated B-VID for processing of 281 frames received from EVPN. When an I-SID is associated with more than 282 one B-VID, only one entry is allowed in the table. Rules for 283 preventing this are out of scope of this memo. 285 5.4. Control plane interworking EVPN to ISIS-SPB 287 When a PE receives a BGP NLRI that is new information, it checks if 288 it is the elected DF to communicate this information into ISIS-SPB by 289 checking if the I-SID in the Ethernet Tag ID locally maps to the B- 290 VID it is an elected DF for. Note that if no BEBs in the SPB island 291 have advertised any interest in the I-SID, it will not be associated 292 with any B-VID locally, and therefore not of interest. If the I-SID 293 is of local interest to the SPBM island and the PE is the DF for the 294 B-VID that that I-SID is locally mapped to, a SPBM service identifier 295 and unicast address sub-TLV is constructed/updated for advertisement 296 into ISIS-SPB. 298 The NLRI information advertised into ISIS-SPB is also used to locally 299 populate a forwarding table indexed by B-MAC+I-SID that points to the 300 label stack to impose on the SPBM frame. The bottom label being that 301 offered in the NLRI. 303 5.5. Data plane Interworking 802.1aq SPBM island or PBB-PE to EVPN 305 When an PE receives a frame from the SPBM island in a B-VID for which 306 it is a DF, it looks up the B-MAC/I-SID information to determine the 307 label stack to be added to the frame for forwarding in the EVPN. The 308 PE strips the B-VID information from the frame, adds the label 309 information to the frame and forwards the resulting MPLS packet. 311 5.6. Data plane Interworking EVPN to 802.1aq SPBM island 313 When a PE receives a packet from the EVPN it may infer the B-VID to 314 overwrite in the SPBM frame from the I-SID or by other means (such as 315 via the bottom label in the MPLS stack). 317 If the frame has a local multicast DA, it overwrites the SPsourceID 318 in the frame with the local SPsourceID. 320 5.7. Data plane interworking EVPN to 802.1ah PBB-PE 322 A PBB-PE actually has no subtending PBBN nor concept of B-VID so no 323 frame processing is required. 325 A PBB-PE is required to accept SPBM encoded multicast DAs as if they 326 were 802.1ah encoded multicast DAs. The only information of interest 327 being that it is a multicast frame, and the I-SID encoded in the 328 lower 24 bits. 330 5.8. Multicast Support 332 Not addressed by this memo. 334 6. Other Aspects 336 6.1. Flow Ordering 338 When per I-SID multicast is implemented via PE replication, a stable 339 network will preserve frame ordering between known unicast and 340 broadcast/unknown/multicast traffic (e.g. race conditions will not 341 exist). This cannot be guaranteed when multicast is used in the EVPN. 343 6.2. Transit 345 Any PE that does not need to participate in the tandem calculations 346 at the B-MAC layer may use the IS-IS overload bit to exclude SPBM 347 tandem paths and behave as pure interworking platform. 349 7. Acknowledgements 351 The authors would like to thank Peter Ashwood-Smith, Martin Julien 352 and Janos Farkas for their detailed review of this draft. 354 8. Security Considerations 356 For a future version of this document. 358 9. IANA Considerations 360 For a future version of this document. 362 10. References 364 10.1. Normative References 366 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 367 Requirement Levels", BCP 14, RFC 2119, March 1997. 369 [RFC6329] Fedyk et.al. "IS-IS Extensions Supporting IEEE 802.1aq 370 Shortest Path Bridging", IETF RFC 6329, April 2012 372 [EVPN] Aggarwal et.al. "BGP MPLS Based Ethernet VPN", IETF work 373 in progress, draft-ietf-l2vpn-evpn-11, October 2014 375 10.2. Informative References 377 [802.1aq] 378 802.1aq(2012) IEEE Standard for Local and Metropolitan 379 Area Networks: Bridges and Virtual Bridged Local Area 380 Networks - Amendment 9: Shortest Path Bridging 382 [PBB-EVPN] Sajassi et.al. "PBB E-VPN", IETF work in progress, 383 draft-ietf-l2vpn-pbb-evpn-08, October 2014 385 [802.1Q] 386 802.1Q (2011) IEEE Standard for Local and metropolitan 387 area networks--Media Access Control (MAC) Bridges and 388 Virtual Bridged Local Area Networks 390 11. Authors' Addresses 392 Dave Allan (editor) 393 Ericsson 394 300 Holger Way 395 San Jose, CA 95134 396 USA 397 Email: david.i.allan@ericsson.com 399 Jeff Tantsura 400 Ericsson 401 300 Holger Way 402 San Jose, CA 95134 403 Email: jeff.tantsura@ericsson.com 405 Don Fedyk 406 Hewlett-Packard 407 153 Tayor Street 408 Littleton, MA, 01460 409 don.fedyk@hp.com 411 Ali Sajassi 412 Cisco 413 170 West Tasman Drive 414 San Jose, CA 95134, US 415 Email: sajassi@cisco.com