idnits 2.17.1 draft-boutros-l2vpn-evpn-vpws-03.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 : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (February 14, 2014) is 3717 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Missing Reference: 'MEF' is mentioned on line 96, but not defined == Missing Reference: 'RFC2119' is mentioned on line 125, but not defined == Missing Reference: 'RFC4448' is mentioned on line 273, but not defined == Unused Reference: 'KEYWORDS' is defined on line 359, but no explicit reference was found in the text == Unused Reference: 'EVPN-REQ' is defined on line 364, but no explicit reference was found in the text == Unused Reference: 'PBB-EVPN' is defined on line 370, but no explicit reference was found in the text == Outdated reference: A later version (-07) exists of draft-ietf-l2vpn-evpn-req-00 == Outdated reference: A later version (-11) exists of draft-ietf-l2vpn-evpn-04 == Outdated reference: A later version (-10) exists of draft-ietf-l2vpn-pbb-evpn-05 Summary: 0 errors (**), 0 flaws (~~), 10 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 INTERNET-DRAFT Sami Boutros 3 Intended Status: Standard Track Ali Sajassi 4 Samer Salam 5 Cisco Systems 7 John Drake 8 Juniper Networks 10 Jeff Tantsura 11 Ericsson 13 Dirk Steinberg 14 Steinberg Consulting 15 Expires: August 18, 2014 February 14, 2014 17 VPWS support in E-VPN 18 draft-boutros-l2vpn-evpn-vpws-03.txt 20 Abstract 22 This document describes how E-VPN can be used to support virtual 23 private wire service (VPWS) in MPLS/IP networks. E-VPN enables the 24 following characteristics for VPWS: single-active as well as all- 25 active multi-homing with flow-based load-balancing, eliminates the 26 need for single-segment and multi-segment PW signaling, and provides 27 fast protection using data-plane prefix independent convergence upon 28 node or link failure. 30 Status of this Memo 32 This Internet-Draft is submitted to IETF in full conformance with the 33 provisions of BCP 78 and BCP 79. 35 Internet-Drafts are working documents of the Internet Engineering 36 Task Force (IETF), its areas, and its working groups. Note that 37 other groups may also distribute working documents as 38 Internet-Drafts. 40 Internet-Drafts are draft documents valid for a maximum of six months 41 and may be updated, replaced, or obsoleted by other documents at any 42 time. It is inappropriate to use Internet-Drafts as reference 43 material or to cite them other than as "work in progress." 45 The list of current Internet-Drafts can be accessed at 46 http://www.ietf.org/1id-abstracts.html 47 The list of Internet-Draft Shadow Directories can be accessed at 48 http://www.ietf.org/shadow.html 50 Copyright and License Notice 52 Copyright (c) 2014 IETF Trust and the persons identified as the 53 document authors. All rights reserved. 55 This document is subject to BCP 78 and the IETF Trust's Legal 56 Provisions Relating to IETF Documents 57 (http://trustee.ietf.org/license-info) in effect on the date of 58 publication of this document. Please review these documents 59 carefully, as they describe your rights and restrictions with respect 60 to this document. Code Components extracted from this document must 61 include Simplified BSD License text as described in Section 4.e of 62 the Trust Legal Provisions and are provided without warranty as 63 described in the Simplified BSD License. 65 Table of Contents 67 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 68 1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3 69 1.2 Requirements . . . . . . . . . . . . . . . . . . . . . . . . 4 70 2. BGP Extensions . . . . . . . . . . . . . . . . . . . . . . . . 5 71 3 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 72 4 EVPN Comparison to PW Signaling . . . . . . . . . . . . . . . . 6 73 5 ESI Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . . 7 74 6 ESI value derivation and Eth-tag setting . . . . . . . . . . . . 7 75 7 VPWS with multiple sites . . . . . . . . . . . . . . . . . . . . 8 76 8 Security Considerations . . . . . . . . . . . . . . . . . . . . 8 77 9 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8 78 10 References . . . . . . . . . . . . . . . . . . . . . . . . . . 8 79 10.1 Normative References . . . . . . . . . . . . . . . . . . . 8 80 10.2 Informative References . . . . . . . . . . . . . . . . . . 8 81 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9 83 1 Introduction 85 This document describes how EVPN can be used to support virtual 86 private wire service (VPWS) in MPLS/IP networks. The use of EVPN 87 mechanisms for VPWS brings the benefits of EVPN to p2p services. 88 These benefits include single-active redundancy as well as all-active 89 redundancy with flow-based load-balancing. Furthermore, the use of 90 EVPN for VPWS eliminates the need for signaling single-segment and 91 multi-segment PWs for p2p Ethernet services. 93 [EVPN] has the ability to forward customer traffic to/from a given 94 customer Attachment Circuit (AC), aka Ethernet Segment in EVPN 95 terminology, without any MAC lookup. This capability is ideal in 96 providing p2p services (aka VPWS services). [MEF] defines Ethernet 97 Virtual Private Line (EVPL) service as p2p service between a pair of 98 ACs (designated by VLANs). EVPL can be considered as a VPWS with only 99 two ACs. In delivering an EVPL service, the traffic forwarding 100 capability of EVPN based on the exchange of a pair of Ethernet AD 101 routes is used; whereas, for more general VPWS, traffic forwarding 102 capability of EVPN based on the exchange of a group of Ethernet AD 103 routes (one Ethernet AD route per AC/segment) is used. In a VPWS 104 service, the traffic from an originating Ethernet Segment can be 105 forwarded only to a single destination Ethernet Segment; hence, no 106 MAC lookup is needed and the MPLS label associated with the per-EVI 107 Ethernet AD route can be used in forwarding user traffic to the 108 destination AC. 110 In current PW redundancy mechanisms, convergence time is a function 111 of control plane convergence characteristics. However, with EVPN it 112 is possible to attain faster convergence through the use of data- 113 plane prefix independent convergence, upon node or link failure. 115 This document proposes the use of the Ethernet AD route to signal 116 labels for P2P Ethernet services. As with EVPN, the Ethernet Segment 117 route can be used to synchronize state between the PEs attached to 118 the same multi-homed Ethernet Segment. 120 1.1 Terminology 122 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 123 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 124 document are to be interpreted as described in RFC 2119 [RFC2119]. 126 MAC: Media Access Control 128 MPLS: Multi Protocol Label Switching. 130 OAM: Operations, Administration and Maintenance. 132 PE: Provide Edge Node. 134 CE: Customer Edge device e.g., host or router or switch. 136 EVI: EVPN Instance. 138 Single-Active Mode: When a device or a network is multi-homed to two 139 or more PEs and when only a single PE in such redundancy group can 140 forward traffic to/from the multi-homed device or network for a given 141 VLAN, then such multi-homing or redundancy is referred to as "Single- 142 Active". 144 All-Active: When a device is multi-homed to two or more PEs and when 145 all PEs in such redundancy group can forward traffic to/from the 146 multi-homed device for a given VLAN, then such multi-homing or 147 redundancy is referred to as "All-Active". 149 1.2 Requirements 151 1. EPL service access circuit maps to the whole Ethernet port. 153 2. EVPL service access circuits are VLANs on single or double tagged 154 trunk ports. Each VLAN individually will be considered to be an 155 endpoint for an EVPL service, without any direct dependency on any 156 other VLANs on the trunk. Other VLANs on the same trunk could also be 157 used for EVPL services, but could also be associated with other 158 services. 160 3. If multiple VLANs on the same trunk are associated with EVPL 161 services, the respective remote endpoints of these EVPLs could be 162 dispersed across any number of PEs, i.e. different VLANs may lead to 163 different destinations. 165 4. The VLAN tag on the access trunk only has PE-local significance. 166 The VLAN tag on the remote end could be different, and could also be 167 double tagged when the other side is single tagged. 169 5. Also, multiple EVPL service VLANs on the same trunk could belong 170 to the same EVPN instance (EVI), or they could belong to different 171 EVIs. This should be purely an administrative choice of the network 172 operator. 174 6. A given access trunk could have hundreds of EVPL services, and a 175 given PE could have thousands of EVPLs configured. It must be 176 possible to configure multiple EVPL services within the same EVI. 178 7. Local access circuits configured to belong to a given EVPN 179 instance could also belong to different physical access trunks. 181 2. BGP Extensions 183 [EVPN] defines a new BGP NLRI for advertising different route types 184 for EVPN operation. This document does not define any new BGP 185 messages, but rather re-purposes one of the routes as described next. 187 This document proposes the use of the per EVI Ethernet AD route to 188 signal P2P services. The Ethernet Segment Identifier field is set to 189 the ESI of the attachment circuit of the VPWS service instance. The 190 Ethernet Tag field is set to 0 in the case of an Ethernet Private 191 Wire service, and to the VLAN identifier associated with the service 192 for Ethernet Virtual Private Wire service. The Route-Target (RT) 193 extended community that identifies the VPN associated with the p2p 194 EVPLs where each EVPL is identified by . 196 3 Operation 198 The following figure shows an example of a P2P service deployed with 199 EVPN. 200 Ethernet Ethernet 201 Native |<--------- EVPN Instance ----------->| Native 202 Service | | Service 203 (AC) | |<-PSN1->| |<-PSN2->| | (AC) 204 | V V V V V V | 205 | +-----+ +-----+ +-----+ +-----+ | 206 +----+ | | PE1 |======|ASBR1|==|ASBR2|===| PE3 | | +----+ 207 | |-------+-----+ +-----+ +-----+ +-----+-------| | 208 | CE1| | | |CE2 | 209 | |-------+-----+ +-----+ +-----+ +-----+-------| | 210 +----+ | | PE2 |======|ASBR3|==|ASBR4|===| PE4 | | +----+ 211 ^ +-----+ +-----+ +-----+ +-----+ ^ 212 | Provider Edge 1 ^ Provider Edge 2 | 213 | | | 214 | | | 215 | EVPN Inter-provider point | 216 | | 217 |<---------------- Emulated Service -------------------->| 219 iBGP sessions are established between PE1, PE2, ASBR1 and ASBR3, 220 possibly via a BGP route-reflector. Similarly, iBGP sessions are 221 established between PE3, PE4, ASBR2 and ASBR4. eBGP sessions are 222 established among ASBR1, ASBR2, ASBR3, and ASBR4. 224 All PEs and ASBRs are enabled for the EVPN SAFI, and exchange EVPN 225 Ethernet A-D routes - one route per AC. The ASBRs re-advertise the 226 Ethernet A-D routes with Next Hop attribute set to their IP 227 addresses. The link between the CE and the PE is either a C-tagged or 228 S-tagged interface, as described in [802.1Q], that can carry a single 229 VLAN tag or two nested VLAN tags. This interface is set up as a trunk 230 with multiple VLANs. 232 A VPWS with multiple sites or multiple EVPL services on the same CE 233 port can be included in one EVI between 2 or more PEs. An Ethernet 234 Tag corresponding to each P2P connection and known to both PEs is 235 used to identify the services multiplexed in the same EVI. 237 For CE single-homing the ESI field must be set to 0 in the Ethernet 238 AD route, the field will be set to the AC-ID of the EVPL or 239 EPL service. 241 For CE multi-homing, the Ethernet AD Route encodes the ESI associated 242 with the CE. This allows flow-based load-balancing of traffic between 243 PEs connected to the same multi-homed CE. The AC ID encoded in the 244 tag field MUST be the same on both PEs attached to the site. The 245 Ethernet Segment route may be used too, for discovery of multi-homed 246 CEs. In all cases traffic follows the transport paths, which may be 247 asymmetric. 249 The field of the EVI EAD route represents the AC-ID of the 250 EPL and EVPL service. 252 EPL service need to be identified by a non 0 field in the 253 Ethernet AD route. 255 The field value representing the AC-ID of the EPL/EVPL 256 service of the remote side may be equal to the local side. 258 An operator may choose to associate many per EVI EAD routes with 259 different ESIs and tags to the same Route-Target (RT) extended 260 community attribute. As such, the association of per EVI EAD routes 261 to the same RT is a network operator design choice. 263 Per ES EAD route can be used for mass withdraw to withdraw all per 264 EVI EAD routes associated with the multi-home site on a given PE. 266 The VLANs on the two ACs of a given EVPL service may have different 267 VLANs. EVPN doesn't perform that translation, and that it should be 268 handled by the Ethernet interface. 270 4 EVPN Comparison to PW Signaling 272 In EVPN, service endpoint discovery and label signaling are done 273 concurrently using BGP. Whereas, with VPWS based on [RFC4448], label 274 signaling is done via LDP and service endpoint discovery is either 275 through manual provisioning or through BGP. 277 In existing implementation of VPWS using pseudowires(PWs), redundancy 278 is limited to single-active mode, while with EVPN implementation of 279 VPWS both single-active and all-active redundancy modes can be 280 supported. 282 In existing implementation with PWs, backup PWs are not used to carry 283 traffic, while with EVPN, traffic can be load-balanced among 284 different PEs multi-homed to a single CE. 286 Upon link or node failure, EVPN can trigger failover with the 287 withdrawal of a single BGP route per EVPL service or multiple EVPL 288 services, whereas with VPWS PW redundancy, the failover sequence 289 requires exchange of two control plane messages: one message to 290 deactivate the group of primary PWs and a second message to activate 291 the group of backup PWs associated with the access link. Finally, 292 EVPN may employ data plane local repair mechanisms not available in 293 VPWS. 295 5 ESI Bandwidth 297 The ESI Bandwidth will be encoded using the Link Bandwidth Extended 298 community defined in [draft-ietf-idr-link-bandwidth] and associated 299 with the Ethernet AD route used to realize the EVPL services. 301 When a PE receives this attribute for a given EVPL it MUST request 302 the required bandwidth from the PSN towards the other EVPL service 303 destination PE originating the message. When resources are allocated 304 from the PSN for a given EVPL service, then the PSN SHOULD account 305 for the Bandwidth requested by this EVPL service. 307 In the case where PSN resources are not available, the PE receiving 308 this attribute MUST re-send its local Ethernet AD routes for this 309 EVPL service with the ESI Bandwidth = All FFs to declare that the 310 "PSN Resources Unavailable". 312 The scope of the ESI Bandwidth is limited to only one Autonomous 313 System. 315 6 ESI value derivation and Eth-tag setting 317 The ESI value is set per [EVPN] procedures - e.g., it is set to 0 318 for single home sites and can be manually configured or auto-derived 319 for multi-homed sites. 321 The field in the Ethernet A-D per EVI route is set to the 322 AC-ID representing the EPL or EVPL service. This is different from 323 the baseline [EVPN] Where field is set only for VLAN-aware 324 bundle service. 326 The AC-ID value SHOULD be the same at both sides of the EPL or EVPL 327 service and it SHOULD be unique within an AS. 329 "EVI" for VPWS services MUST be different from multipoint services 330 specified in baseline [EVPN]. This implies the corresponding RTs for 331 VPWS and multipoint services needs to be different. 333 AC-IDs in the field MUST be unique within one AS, an ASBR 334 MAY be required to perform AC-IDs translations if the AC-IDs are not 335 unique across multiple ASs. 337 Local and remote AC-IDs of a given EVPL or EPL service, are 338 configured by an operator to connect the 2 sides of the EPL/EVPL 339 services at both sides of the services. 341 7 VPWS with multiple sites 343 The VPWS among multiple sites (full mesh of P2P connections - one per 344 pair of sites) that can be setup automatically without any explicit 345 provisioning of P2P connections among the sites is outside the scope 346 of this document. 348 8 Security Considerations 350 This document does not introduce any additional security constraints. 351 9 IANA Considerations 353 TBD 355 10 References 357 10.1 Normative References 359 [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate 360 Requirement Levels", BCP 14, RFC 2119, March 1997. 362 10.2 Informative References 364 [EVPN-REQ] A. Sajassi, R. Aggarwal et. al., "Requirements for 365 Ethernet VPN", draft-ietf-l2vpn-evpn-req-00.txt. 367 [EVPN] A. Sajassi, R. Aggarwal et. al., "BGP MPLS Based Ethernet 368 VPN", draft-ietf-l2vpn-evpn-04.txt. 370 [PBB-EVPN] A. Sajassi et. al., "PBB-EVPN", draft-ietf-l2vpn-pbb-evpn- 371 05.txt. 373 [draft-ietf-idr-link-bandwidth] P. Mohapatra, R. Fernando, "BGP Link 374 Bandwidth Extended Community", draft-ietf-idr-link-bandwidth-06.txt 376 Authors' Addresses 378 Sami Boutros 379 Cisco 380 Email: sboutros@cisco.com 382 Ali Sajassi 383 Cisco 384 Email: sajassi@cisco.com 386 Samer Salam 387 Cisco 388 Email: ssalam@cisco.com 390 John Drake 391 Juniper Networks 392 Email: jdrake@juniper.net 394 Jeff Tantsura 395 Ericsson 396 Email: jeff.tantsura@ericsson.com 398 Dirk Steinberg 399 Steinberg Consulting 400 Email: dws@steinbergnet.net 402 Patrice Brissette 403 Cisco 404 Email: pbrisset@cisco.com