idnits 2.17.1 draft-snr-bess-pbb-evpn-isid-cmacflush-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 : ---------------------------------------------------------------------------- ** The document seems to lack an Introduction section. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == Line 122 has weird spacing: '... |stb vES...' -- The document date (January 15, 2018) is 2286 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 section? 'RFC2119' on line 371 looks like a reference Summary: 1 error (**), 0 flaws (~~), 2 warnings (==), 2 comments (--). 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 K. Nagaraj 5 Nokia 7 M. Miyake 8 T. Matsuda 9 Softbank 11 Expires: July 19, 2018 January 15, 2018 13 PBB-EVPN ISID-based CMAC-Flush 14 draft-snr-bess-pbb-evpn-isid-cmacflush-03 16 Abstract 18 RFC7623 defines how Provider Backbone Bridging (PBB) can be combined 19 with Ethernet VPN (EVPN) to deploy ELAN services in very large MPLS 20 networks. RFC7623 also describes how Single-Active Multi-homing and 21 per-ISID Load-Balancing can be provided to access devices and 22 aggregation networks. In order to speed up the network convergence in 23 case of failures on Single-Active Multi-Homed Ethernet Segments, 24 RFC7623 defines a CMAC-Flush mechanism that works for different 25 Ethernet Segment BMAC address allocation models. This document 26 complements those CMAC-Flush procedures for cases in which no PBB- 27 EVPN Ethernet Segments are defined (ESI 0) and an ISID-based CMAC- 28 Flush granularity is desired. 30 Status of this Memo 32 This Internet-Draft is submitted 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 Internet- 38 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/ietf/1id-abstracts.txt 47 The list of Internet-Draft Shadow Directories can be accessed at 48 http://www.ietf.org/shadow.html 50 This Internet-Draft will expire on July 19, 2018. 52 Copyright Notice 54 Copyright (c) 2018 IETF Trust and the persons identified as the 55 document authors. All rights reserved. 57 This document is subject to BCP 78 and the IETF Trust's Legal 58 Provisions Relating to IETF Documents 59 (http://trustee.ietf.org/license-info) in effect on the date of 60 publication of this document. Please review these documents 61 carefully, as they describe your rights and restrictions with respect 62 to this document. Code Components extracted from this document must 63 include Simplified BSD License text as described in Section 4.e of 64 the Trust Legal Provisions and are provided without warranty as 65 described in the Simplified BSD License. 67 Table of Contents 69 1. Problem Statement . . . . . . . . . . . . . . . . . . . . . . . 2 70 2. Solution requirements . . . . . . . . . . . . . . . . . . . . . 4 71 3. EVPN BGP Encoding for ISID-based CMAC-flush . . . . . . . . . . 5 72 4. Solution description . . . . . . . . . . . . . . . . . . . . . 6 73 4.1 ISID-based CMAC-Flush activation procedures . . . . . . . . 6 74 4.2 CMAC-Flush generation . . . . . . . . . . . . . . . . . . . 7 75 4.3 CMAC-Flush process upon receiving a CMAC-Flush 76 notification . . . . . . . . . . . . . . . . . . . . . . . . 7 77 5. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . 8 78 6. Conventions used in this document . . . . . . . . . . . . . . . 8 79 7. Security Considerations . . . . . . . . . . . . . . . . . . . . 9 80 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 9 81 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 82 9.1 Normative References . . . . . . . . . . . . . . . . . . . . 9 83 9.2 Informative References . . . . . . . . . . . . . . . . . . . 9 84 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9 85 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 9 86 17. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 10 88 1. Problem Statement 90 RFC7623 defines how Provider Backbone Bridging (PBB) can be combined 91 with Ethernet VPN (EVPN) to deploy ELAN services in very large MPLS 92 networks. RFC7623 also describes how Single-Active Multi-homing and 93 per-ISID Load-Balancing can be provided to access devices and 94 aggregation networks. When Access Ethernet/MPLS Networks exists, 95 [vES] describes how virtual ES can be associated to a group of 96 Ethernet Virtual Circuits (EVCs) or even Pseudowires (PWs). In order 97 to speed up the network convergence in case of failures on Single- 98 Active Multi-Homed Ethernet Segments, RFC7623 defines a CMAC-Flush 99 mechanism that works for different Ethernet Segment BMAC address 100 allocation models. 102 In some cases, the administrative entities that manage the access 103 devices or aggregation networks, don't demand Multi-Homing Ethernet 104 Segments (ES) from the PBB-EVPN provider, but simply multiple single- 105 homed ES. If that is the case, the PBB-EVPN network is no longer 106 aware of the redundancy offered by the access administrative entity. 107 Figure 1 shows an example where the PBB-EVPN network provides four 108 different Attachment Circuits (ACs) for ISID1, with those ACs not 109 being part of any ES or vES (therefore they are referred to as null 110 vES). 112 <--PBB-EVPN Network---> 114 ISID1 vES +-----+ +-----+ 115 +----+ null| PE1 +---------+ PE3 |vES null 116 |CE1 +--------+ BM1 | | BM3 | +---------+ 117 +-+--+ act| | | |===== | 118 | G.8032 +-+---+ +---+-+ | \act | ISID1 119 | Access | | | \ +-+--+ 120 | Ring | IP/MPLS | | ==|CE3 | 121 | | | | / +-+--+ 122 |stb vES +-+---+ +---+-+ | /stb | 123 +-+--+ null| PE2 | | PE4 +----- | 124 |CE2 +--------+ BM2 | | BM4 | +---------+ 125 +----+ act| +---------+ |vES null 126 ISID1 +-----+ +-----+ <-MPLS Ag-> 127 Network 129 Figure 1 PBB-EVPN and non-ES based redundancy 131 In the example in Figure 1, CE1 and CE2 provide redundant 132 connectivity for ISID1 through the use of G.8032 Ethernet Ring 133 Protection Switching. CE3 provides redundant active-standby PW 134 connectivity for ISID1. In the two cases the ACs are connected to 135 null ES, hence the PEs will keep their ACs active and the CEs will be 136 responsible for the per-ISID load balancing while avoiding loops. 138 For instance, CE2 will block its link to CE1 and CE3 will block its 139 forwarding path to PE4. In this situation, a failure in one of the 140 redundant ACs will make the CEs to start using their redundant paths, 141 however those failures will not trigger any CMAC-Flush procedures in 142 the PEs. For example, if the active PW from CE3 fails, PE3 will not 143 issue any CMAC-Flush message and therefore the remote PEs will 144 continue pointing at PE3's BMAC to reach CE3's CMACs, until the CMACs 145 age out in the ISID1 FDBs. 147 RFC7623 provides a CMAC-Flush solution based on a shared BMAC update 148 along with the MAC Mobility extended community where the sequence 149 number is incremented. However, while that procedure could be used in 150 the example of Figure 1, it would result in unnecessary flushing of 151 unaffected ISIDs on the remote PEs, and subsequent flooding. 153 This document describes an extension of the RFC7623 CMAC-Flush 154 procedures, so that in the above failure example, PE3 can trigger a 155 CMAC-Flush notification that makes PE1, PE2 and PE4 flush all the 156 CMACs associated to PE3's BMAC and (only) ISID1. This new CMAC-Flush 157 procedure explained in this document will be referred to as "PBB-EVPN 158 ISID-based CMAC-Flush" and can be used in PBB-EVPN networks with null 159 or non-null (virtual) Ethernet Segments. 161 2. Solution requirements 163 The following requirements must be met by the CMAC-Flush solution 164 described in this document: 166 a) The solution MUST solve black-hole scenarios in case of failures 167 on null ES ACs (Attachment Circuits not associated to ES, that is, 168 ESI=0) when the access device/network is responsible for the 169 redundancy. 171 b) This extension SHOULD work with Single-Active non-null ES and 172 virtual ES, irrespective of the PE BMAC address assignment 173 (dedicated per-ES BMAC or shared BMAC). 175 c) In case of failure on the egress PE, the solution MUST provide a 176 CMAC-Flush notification at BMAC AND ISID granularity level. 178 d) The solution MUST provide a reliable CMAC-Flush notification in 179 PBB-EVPN networks that use Route-Reflectors (RRs). 181 e) The solution MUST coexist in RFC7623-compliant networks where 182 there are systems not supporting this extension. 184 f) The solution SHOULD be enabled/disabled by an administrative 185 option on a per-PE and per-ISID basis. 187 3. EVPN BGP Encoding for ISID-based CMAC-flush 189 The solution does not use any new BGP attributes but reuses the MAC 190 Mobility extended community as an indication of CMAC-Flush (as in 191 RFC7623) and encodes the ISID in the Ethernet Tag field of the MAC/IP 192 route. As a reference, Figure 2 shows the MAC Mobility extended 193 community and the MAC/IP route that are used in this document as a 194 CMAC-Flush notification. 196 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 1 197 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 198 | Type=0x06 | Sub-Type=0x03 | Flags | Reserved=0 | 199 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 200 | Sequence Number | 201 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 203 +---------------------------------------+ 204 | RD | 205 +---------------------------------------+ 206 | ESI = 0 | 207 +---------------------------------------+ 208 | Ethernet Tag ID = ISID | 209 +---------------------------------------+ 210 | MAC Address Length = 48 | 211 +---------------------------------------+ 212 | BMAC Address | 213 +---------------------------------------+ 214 | IP Address Length = 0 | 215 +---------------------------------------+ 216 | MPLS Label1 | 217 +---------------------------------------+ 219 Figure 2 CMAC-Flush notification encoding: BMAC/ISID route 221 Where: 223 o The route's RD and RT are the ones corresponding to its EVI. 224 Alternatively to the EVI's RT, the route MAY be tagged with an RT 225 auto-derived from the Ethernet Tag (ISID) instead. RFC7623 226 describes how the RT can be derived from the ISID. 228 o The Ethernet Tag encodes the ISID for which the PE that receives 229 the route must flush the CMACs upon reception of the route. 231 o The MAC address field encodes the BMAC Address for which the PE 232 that receives the route must flush the CMACs upon reception of the 233 route. 235 o The MAC Mobility extended community is used as in RFC7623, where a 236 delta in the sequence number between two updates for the same 237 BMAC/ISID will be interpreted as a CMAC-flush notification for the 238 corresponding BMAC and ISID. 240 All the other fields are set and used as defined in RFC7623. This 241 document will refer to this route as the BMAC/ISID route, as opposed 242 to the RFC7623 BMAC/0 route (BMAC route sent with Ethernet Tag = 0). 244 Note that this BMAC/ISID route will be accepted and reflected by any 245 RFC7432-compliant RR, since no new attributes or values are used. A 246 PE receiving the route will process the received BMAC/ISID update 247 only in case of supporting the procedures described in this 248 document. 250 4. Solution description 252 Figure 1 will be used in the description of the solution. CE1, CE2 253 and CE3 are connected to ACs associated to ISID1, where no (Multi- 254 Homed) Ethernet Segments have been enabled. All the ACs are 255 operationally active and ready to forward frames. 257 Enabling or disabling ISID-based CMAC-Flush SHOULD be an 258 administrative choice on the system that MAY be configured per ISID 259 (I-Component). When enabled on a PE: 261 a) The PE will be able to generate BMAC/ISID routes as CMAC-Flush 262 notifications for the remote PEs. 264 b) The PE will be able to process BMAC/ISID routes received from 265 remote PEs. 267 When ISID-based CMAC-Flush is disabled, the PE will follow the 268 RFC7623 procedures for CMAC-flush. 270 These new CMAC-flush procedures are described in sections 4.1, 4.2 271 and 4.3 respectively: 273 o ISID-based CMAC-flush activation 274 o CMAC-flush notification generation upon AC failures 275 o CMAC-flush process upon receiving a CMAC-Flush notification 277 4.1 ISID-based CMAC-Flush activation procedures 278 The following behavior MUST be followed by the PBB-EVPN PEs (see 279 Figure 1): 281 o As in RFC7623, each PE has previously advertised a shared BMAC in a 282 BMAC/0 route (BM1, BM2, BM3 and BM4 respectively). This is the BMAC 283 that each PE will use as BMAC SA (Source Address) when 284 encapsulating the frames received on any local single-homed AC. 285 Each PE will import the received BMAC/0 routes from the remote PEs 286 and will install the BMACs in its B-component MAC-VRF. For 287 instance, PE1 will advertise BM1/0 and will install BM2, BM3 and 288 BM4 in its MAC-VRF. 290 o Assuming ISID-based CMAC-Flush is activated for ISID 1, the PEs 291 will advertise the shared BMAC with ISID 1 encoded in the Ethernet 292 Tag. That is, PE1 will advertise BM1/1 and will receive BM2/1, 293 BM3/1 and BM4/1. The receiving PEs MUST use these BMAC/ISID routes 294 only for CMAC-Flush procedures and they MUST NOT be used to 295 add/withdraw any BMAC entry in the MAC-VRFs. As per RFC7623, only 296 BMAC/0 routes can be used to add/withdraw BMACs in the MAC-VRFs. 298 o The above procedure MAY also be used for dedicated BMACs. 300 4.2 CMAC-Flush generation 302 If, for instance, there is a failure on PE1's AC, PE1 will generate 303 an update including BM1/1 along with the MAC Mobility extended 304 community where the Sequence Number has been incremented. The 305 reception of the BM1/1 with a delta in the sequence number will 306 trigger the CMAC-Flush procedures on the receiving PEs. 308 o An AC going operationally down MUST generate a BMAC/ISID with a 309 higher Sequence Number. If the AC going down makes the entire local 310 ISID go operationally down, the PE will withdraw the BMAC/ISID 311 route for the ISID. 313 o An AC going operationally up SHOULD NOT generate any BMAC/ISID 314 update, unless it activates its corresponding ISID, in which case 315 the PE will advertise the BMAC/ISID route. 317 o An AC receiving a CMAC-Flush notification from the access network, 318 e.g. by G.8032, MAY propagate it to the remote PEs by generating a 319 BMAC/ISID update with higher Sequence Number. 321 4.3 CMAC-Flush process upon receiving a CMAC-Flush notification 323 A PE receiving a CMAC-Flush notification will follow these 324 procedures: 326 o A received BMAC/ISID route (with non-zero ISID) MUST NOT add/remove 327 any BMAC to/from the MAC-VRF. 329 o An update of a previously received BMAC/ISID route with a delta 330 Sequence Number, MUST flush all the CMACs associated to that ISID 331 and BMAC. CMACs associated to the same ISID but different BMAC MUST 332 NOT be flushed. 334 o A received BMAC/ISID withdraw (with non-zero ISID) MUST flush all 335 the CMACs associated to that BMAC and ISID. 337 Note that the CMAC-Flush procedures described in RFC7623 for BMAC/0 338 routes are still valid and a PE receiving RFC7623 CMAC-flush 339 notification messages MUST observe the behavior specified in RFC7623. 341 5. Conclusions 343 The ISID-based CMAC-Flush solution described in this document has the 344 following benefits: 346 a) The solution solves black-hole scenarios in case of failures on 347 null ES ACs, since the CMAC-flush procedures are independent of 348 the Ethernet Segment definition. 350 b) This extension can also be used with Single-Active non-null ES and 351 virtual ES, irrespective of the PE BMAC address assignment 352 (dedicated per-ES BMAC or shared BMAC). 354 c) It provides a CMAC-Flush notification at BMAC AND ISID granularity 355 level, therefore flushing a minimum number of CMACs and reducing 356 the amount of flooding in the network. 358 d) It provides a reliable CMAC-Flush notification in PBB-EVPN 359 networks that use RRs. RRs will propagate the CMAC-flush 360 notifications for all the affected ISIDs and irrespective of the 361 order in which the notifications make it to the RR. 363 e) The solution can coexist in a network with systems supporting or 364 not supporting the CMAC-flush extensions. 366 6. Conventions used in this document 368 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 369 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 370 document are to be interpreted as described in RFC-2119 [RFC2119]. 372 In this document, these words will appear with that interpretation 373 only when in ALL CAPS. Lower case uses of these words are not to be 374 interpreted as carrying RFC-2119 significance. 376 In this document, the characters ">>" preceding an indented line(s) 377 indicates a compliance requirement statement using the key words 378 listed above. This convention aids reviewers in quickly identifying 379 or finding the explicit compliance requirements of this RFC. 381 7. Security Considerations 383 This section will be added in future versions. 385 8. IANA Considerations 387 9. References 389 9.1 Normative References 391 [RFC7432]Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A., 392 Uttaro, J., Drake, J., and W. Henderickx, "BGP MPLS-Based Ethernet 393 VPN", RFC 7432, DOI 10.17487/RFC7432, February 2015, . 396 [RFC7623]Sajassi, A., Ed., Salam, S., Bitar, N., Isaac, A., and W. 397 Henderickx, "Provider Backbone Bridging Combined with Ethernet VPN 398 (PBB-EVPN)", RFC 7623, September 2015, . 401 9.2 Informative References 403 [vES] Sajassi et al. "EVPN Virtual Ethernet Segment", draft-sajassi- 404 bess-evpn-virtual-eth-segment-01, work-in-progress, July 6, 2015. 406 10. Acknowledgments 408 The authors want to thank Vinod Prabhu, Sriram Venkateswaran, Laxmi 409 Padakanti, Ranganathan Boovaraghavan for their review and 410 contributions. 412 11. Contributors 413 17. Authors' Addresses 415 Jorge Rabadan 416 Nokia 417 777 E. Middlefield Road 418 Mountain View, CA 94043 USA 419 Email: jorge.rabadan@nokia.com 421 Senthil Sathappan 422 Nokia 423 701 E. Middlefield Road 424 Mountain View, CA 94043 USA 425 Email: senthil.sathappan@nokia.com 427 Kiran Nagaraj 428 Nokia 429 701 E. Middlefield Road 430 Mountain View, CA 94043 USA 431 Email: kiran.nagaraj@nokia.com 433 Masahiro Miyake 434 Softbank 435 Email: masahiro.miyake@g.softbank.co.jp 437 Taku Matsuda 438 Softbank 439 Email: taku.matsuda@g.softbank.co.jp