idnits 2.17.1 draft-ietf-isis-segment-routing-extensions-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 3 instances of lines with private range IPv4 addresses in the document. If these are generic example addresses, they should be changed to use any of the ranges defined in RFC 6890 (or successor): 192.0.2.x, 198.51.100.x or 203.0.113.x. -- The document has examples using IPv4 documentation addresses according to RFC6890, but does not use any IPv6 documentation addresses. 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'ISO10589' ** Obsolete normative reference: RFC 4971 (Obsoleted by RFC 7981) == Outdated reference: A later version (-12) exists of draft-ietf-spring-resiliency-use-cases-01 == Outdated reference: A later version (-08) exists of draft-previdi-6man-segment-routing-header-06 -- Obsolete informational reference (is this intentional?): RFC 5316 (Obsoleted by RFC 9346) Summary: 1 error (**), 0 flaws (~~), 5 warnings (==), 10 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 IS-IS for IP Internets S. Previdi, Ed. 3 Internet-Draft C. Filsfils 4 Intended status: Standards Track A. Bashandy 5 Expires: November 6, 2015 Cisco Systems, Inc. 6 H. Gredler 7 Juniper Networks, Inc. 8 S. Litkowski 9 B. Decraene 10 Orange 11 J. Tantsura 12 Ericsson 13 May 5, 2015 15 IS-IS Extensions for Segment Routing 16 draft-ietf-isis-segment-routing-extensions-04 18 Abstract 20 Segment Routing (SR) allows for a flexible definition of end-to-end 21 paths within IGP topologies by encoding paths as sequences of 22 topological sub-paths, called "segments". These segments are 23 advertised by the link-state routing protocols (IS-IS and OSPF). 25 This draft describes the necessary IS-IS extensions that need to be 26 introduced for Segment Routing. 28 Requirements Language 30 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 31 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 32 document are to be interpreted as described in RFC 2119 [RFC2119]. 34 Status of This Memo 36 This Internet-Draft is submitted in full conformance with the 37 provisions of BCP 78 and BCP 79. 39 Internet-Drafts are working documents of the Internet Engineering 40 Task Force (IETF). Note that other groups may also distribute 41 working documents as Internet-Drafts. The list of current Internet- 42 Drafts is at http://datatracker.ietf.org/drafts/current/. 44 Internet-Drafts are draft documents valid for a maximum of six months 45 and may be updated, replaced, or obsoleted by other documents at any 46 time. It is inappropriate to use Internet-Drafts as reference 47 material or to cite them other than as "work in progress." 48 This Internet-Draft will expire on November 6, 2015. 50 Copyright Notice 52 Copyright (c) 2015 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 2. Segment Routing Identifiers . . . . . . . . . . . . . . . . . 4 69 2.1. Prefix Segment Identifier (Prefix-SID Sub-TLV) . . . . . 4 70 2.1.1. Flags . . . . . . . . . . . . . . . . . . . . . . . . 6 71 2.1.2. Prefix-SID Propagation . . . . . . . . . . . . . . . 8 72 2.2. Adjacency Segment Identifier . . . . . . . . . . . . . . 9 73 2.2.1. Adjacency Segment Identifier (Adj-SID) Sub-TLV . . . 9 74 2.2.2. Adjacency Segment Identifiers in LANs . . . . . . . . 11 75 2.3. SID/Label Sub-TLV . . . . . . . . . . . . . . . . . . . . 13 76 2.4. SID/Label Binding TLV . . . . . . . . . . . . . . . . . . 14 77 2.4.1. Flags . . . . . . . . . . . . . . . . . . . . . . . . 15 78 2.4.2. Weight . . . . . . . . . . . . . . . . . . . . . . . 16 79 2.4.3. Range . . . . . . . . . . . . . . . . . . . . . . . . 16 80 2.4.4. Prefix Length, Prefix . . . . . . . . . . . . . . . . 18 81 2.4.5. Mapping Server Prefix-SID . . . . . . . . . . . . . . 18 82 2.4.6. SID/Label Sub-TLV . . . . . . . . . . . . . . . . . . 19 83 2.4.7. ERO Metric sub-TLV . . . . . . . . . . . . . . . . . 19 84 2.4.8. IPv4 ERO subTLV . . . . . . . . . . . . . . . . . . . 20 85 2.4.9. IPv6 ERO subTLV . . . . . . . . . . . . . . . . . . . 20 86 2.4.10. Unnumbered Interface ID ERO subTLV . . . . . . . . . 21 87 2.4.11. IPv4 Backup ERO subTLV . . . . . . . . . . . . . . . 22 88 2.4.12. IPv6 Backup ERO subTLV . . . . . . . . . . . . . . . 22 89 2.4.13. Unnumbered Interface ID Backup ERO subTLV . . . . . . 23 90 2.4.14. Prefix ERO and Prefix Backup ERO subTLV path 91 semantics . . . . . . . . . . . . . . . . . . . . . . 24 92 2.5. Multi-Topology SID/Label Binding TLV . . . . . . . . . . 24 93 3. Router Capabilities . . . . . . . . . . . . . . . . . . . . . 25 94 3.1. SR-Capabilities Sub-TLV . . . . . . . . . . . . . . . . . 25 95 3.2. SR-Algorithm Sub-TLV . . . . . . . . . . . . . . . . . . 27 97 4. Non backward compatible changes with prior versions of this 98 document . . . . . . . . . . . . . . . . . . . . . . . . . . 28 99 4.1. Encoding of Multiple SRGBs . . . . . . . . . . . . . . . 28 100 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29 101 5.1. Sub TLVs for Type 22,23,222 and 223 . . . . . . . . . . . 29 102 5.2. Sub TLVs for Type 135,235,236 and 237 . . . . . . . . . . 29 103 5.3. Sub TLVs for Type 242 . . . . . . . . . . . . . . . . . . 30 104 5.4. New TLV Codepoint and Sub-TLV registry . . . . . . . . . 30 105 6. Manageability Considerations . . . . . . . . . . . . . . . . 33 106 7. Security Considerations . . . . . . . . . . . . . . . . . . . 33 107 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 33 108 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 33 109 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 33 110 10.1. Normative References . . . . . . . . . . . . . . . . . . 33 111 10.2. Informative References . . . . . . . . . . . . . . . . . 34 112 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 35 114 1. Introduction 116 Segment Routing (SR) allows for a flexible definition of end-to-end 117 paths within IGP topologies by encoding paths as sequences of 118 topological sub-paths, called "segments". These segments are 119 advertised by the link-state routing protocols (IS-IS and OSPF). Two 120 types of segments are defined, Prefix segments and Adjacency 121 segments. Prefix segments represent an ecmp-aware shortest-path to a 122 prefix, as per the state of the IGP topology. Adjacency segments 123 represent a hop over a specific adjacency between two nodes in the 124 IGP. A prefix segment is typically a multi-hop path while an 125 adjacency segment, in most of the cases, is a one-hop path. SR's 126 control-plane can be applied to both IPv6 and MPLS data-planes, and 127 do not require any additional signaling (other than the regular IGP). 128 For example, when used in MPLS networks, SR paths do not require any 129 LDP or RSVP-TE signaling. Still, SR can interoperate in the presence 130 of LSPs established with RSVP or LDP. 132 This draft describes the necessary IS-IS extensions that need to be 133 introduced for Segment Routing. 135 Segment Routing architecture is described in 136 [I-D.ietf-spring-segment-routing]. 138 Segment Routing use cases are described in 139 [I-D.filsfils-spring-segment-routing-use-cases]. 141 2. Segment Routing Identifiers 143 Segment Routing architecture ([I-D.ietf-spring-segment-routing]) 144 defines different types of Segment Identifiers (SID). This document 145 defines the IS-IS encodings for the IGP-Prefix-SID, the IGP- 146 Adjacency-SID, the IGP-LAN-Adjacency-SID and the Binding-SID. 148 2.1. Prefix Segment Identifier (Prefix-SID Sub-TLV) 150 A new IS-IS sub-TLV is defined: the Prefix Segment Identifier sub-TLV 151 (Prefix-SID sub-TLV). 153 The Prefix-SID sub-TLV carries the Segment Routing IGP-Prefix-SID as 154 defined in [I-D.ietf-spring-segment-routing]. The 'Prefix SID' MUST 155 be unique within a given IGP domain (when the L-flag is not set). 156 The 'Prefix SID' MUST carry an index (when the V-flag is not set) 157 that determines the actual SID/label value inside the set of all 158 advertised SID/label ranges of a given router. A receiving router 159 uses the index to determine the actual SID/label value in order to 160 construct forwarding state to a particular destination router. 162 In many use-cases a 'stable transport' IP Address is overloaded as an 163 identifier of a given node. Because the IP Prefixes may be re- 164 advertised into other levels there may be some ambiguity (e.g. 165 Originating router vs. L1L2 router) for which node a particular IP 166 prefix serves as identifier. The Prefix-SID sub-TLV contains the 167 necessary flags to disambiguate IP Prefix to node mappings. 168 Furthermore if a given node has several 'stable transport' IP 169 addresses there are flags to differentiate those among other IP 170 Prefixes advertised from a given node. 172 A Prefix-SID sub-TLV is associated to a prefix advertised by a node 173 and MAY be present in any of the following TLVs: 175 TLV-135 (IPv4) defined in [RFC5305]. 177 TLV-235 (MT-IPv4) defined in [RFC5120]. 179 TLV-236 (IPv6) defined in [RFC5308]. 181 TLV-237 (MT-IPv6) defined in [RFC5120]. 183 Binding-TLV defined in Section 2.4. 185 When the IP Reachability TLV is propagated across level boundaries, 186 the Prefix-SID sub-TLV SHOULD be kept. 188 The Prefix-SID sub-TLV has the following format: 190 0 1 2 3 191 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 1 192 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 193 | Type | Length | Flags | Algorithm | 194 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 195 | SID/Index/Label (variable) | 196 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 198 where: 200 Type: TBD, suggested value 3 202 Length: variable. 204 Flags: 1 octet field of following flags: 206 0 1 2 3 4 5 6 7 207 +-+-+-+-+-+-+-+-+ 208 |R|N|P|E|V|L| | 209 +-+-+-+-+-+-+-+-+ 211 where: 213 R-Flag: Re-advertisement flag. If set, then the prefix to 214 which this Prefix-SID is attached, has been propagated by the 215 router either from another level (i.e.: from level-1 to level-2 216 or the opposite) or from redistribution (e.g.: from another 217 protocol). 219 N-Flag: Node-SID flag. If set, then the Prefix-SID refers to 220 the router identified by the prefix. Typically, the N-Flag is 221 set on Prefix-SIDs attached to a router loopback address. The 222 N-Flag is set when the Prefix-SID is a Node-SID as described in 223 [I-D.ietf-spring-segment-routing]. 225 P-Flag: no-PHP flag. If set, then the penultimate hop MUST NOT 226 pop the Prefix-SID before delivering the packet to the node 227 that advertised the Prefix-SID. 229 E-Flag: Explicit-Null Flag. If set, any upstream neighbor of 230 the Prefix-SID originator MUST replace the Prefix-SID with a 231 Prefix-SID having an Explicit-NULL value (0 for IPv4 and 2 for 232 IPv6) before forwarding the packet. 234 V-Flag: Value flag. If set, then the Prefix-SID carries a 235 value (instead of an index). By default the flag is UNSET. 237 L-Flag: Local Flag. If set, then the value/index carried by 238 the Prefix-SID has local significance. By default the flag is 239 UNSET. 241 Other bits: MUST be zero when originated and ignored when 242 received. 244 Algorithm: the router may use various algorithms when calculating 245 reachability to other nodes or to prefixes attached to these 246 nodes. Algorithms identifiers are defined in Section 3.2. 247 Examples of these algorithms are metric based Shortest Path First 248 (SPF), various sorts of Constrained SPF, etc. The algorithm field 249 of the Prefix-SID contains the identifier of the algorithm the 250 router has used in order to compute the reachability of the prefix 251 the Prefix-SID is associated to. 253 At origination, the Prefix-SID algorithm field MUST be set to 0 on 254 all Prefix-SID of prefixes computed using SPF algorithm (Shortest 255 Path First). On reception of the Prefix-SID sub-TLV, any non-zero 256 algorithm value MUST match what advertised in the SR-Algorithm 257 sub-TLV (Section 3.2). 259 A router receiving a Prefix-SID from a remote node and with an 260 algorithm value that such remote node has not advertised in the 261 SR-Algorithm sub-TLV (Section 3.2) MUST ignore the Prefix-SID sub- 262 TLV. 264 SID/Index/Label: according to the V and L flags, it contains 265 either: 267 * A 4 octet index defining the offset in the SID/Label space 268 advertised by this router using the encodings defined in 269 Section 3.1. In this case the V and L flags MUST be unset. 271 * A 3 octet local label where the 20 rightmost bits are used for 272 encoding the label value. In this case the V and L flags MUST 273 be set. 275 2.1.1. Flags 277 2.1.1.1. R and N Flags 279 The R-Flag MUST be set for prefixes that are not local to the router 280 and either: 282 advertised because of propagation (Level-1 into Level-2); 284 advertised because of leaking (Level-2 into Level-1); 285 advertised because of redistribution (e.g.: from another 286 protocol). 288 In the case where a Level-1-2 router has local interface addresses 289 configured in one level, it may also propagate these addresses into 290 the other level. In such case, the Level-1-2 router MUST NOT set the 291 R bit. The R-bit MUST be set only for prefixes that are not local to 292 the router and advertised by the router because of propagation and/or 293 leaking. 295 The N-Flag is used in order to define a Node-SID. A router MAY set 296 the N-Flag only if all of the following conditions are met: 298 The prefix to which the Prefix-SID is attached is local to the 299 router. I.e.: the prefix is configured on one of the local 300 interfaces. (e.g.: 'stable transport' loopback). 302 The prefix to which the Prefix-SID is attached MUST have a Prefix 303 length of either /32 (IPv4) or /128 (IPv6). 305 The router MUST ignore the N-Flag on a received Prefix-SID if the 306 prefix has a Prefix length different than /32 (IPv4) or /128 (IPv6). 308 [I-D.ginsberg-isis-prefix-attributes] also defines the N-flag and 309 with the same semantic of the N-flag defined in this document. There 310 will be a transition period where both flags will be used and 311 eventually only the N-flag of the Prefix Attributes will remain. 312 During the transition period implementations supporting the N-flag 313 defined in this document and the N-flag defined in 314 [I-D.ginsberg-isis-prefix-attributes] MUST advertise and parse both 315 flags. In case the received N-flags have different values, the value 316 of the N-flag defined in [I-D.ginsberg-isis-prefix-attributes] 317 prevails. 319 2.1.1.2. E and P Flags 321 When calculating the outgoing label for the prefix, the router MUST 322 take into account E and P flags advertised by the next-hop router, if 323 next-hop router advertised the SID for the prefix. This MUST be done 324 regardless of next-hop router contributing to the best path to the 325 prefix or not. 327 When propagating (either from Level-1 to Level-2 or vice versa) a 328 reachability advertisement originated by another IS-IS speaker, the 329 router MUST set the P-flag and MUST clear the E-flag of the related 330 Prefix-SIDs. 332 The following behavior is associated with the settings of the E and P 333 flags: 335 o If the P-flag is not set then any upstream neighbor of the Prefix- 336 SID originator MUST pop the Prefix-SID. This is equivalent to the 337 penultimate hop popping mechanism used in the MPLS dataplane which 338 improves performance of the ultimate hop. MPLS EXP bits of the 339 Prefix-SID are not preserved to the ultimate hop (the Prefix-SID 340 being removed). If the P-flag is unset the received E-flag is 341 ignored. 343 o If the P-flag is set then: 345 * If the E-flag is not set then any upstream neighbor of the 346 Prefix-SID originator MUST keep the Prefix-SID on top of the 347 stack. This is useful when, e.g., the originator of the 348 Prefix-SID must stitch the incoming packet into a continuing 349 MPLS LSP to the final destination. This could occur at an 350 inter-area border router (prefix propagation from one area to 351 another) or at an inter-domain border router (prefix 352 propagation from one domain to another). 354 * If the E-flag is set then any upstream neighbor of the Prefix- 355 SID originator MUST replace the PrefixSID with a Prefix-SID 356 having an Explicit-NULL value. This is useful, e.g., when the 357 originator of the Prefix-SID is the final destination for the 358 related prefix and the originator wishes to receive the packet 359 with the original EXP bits. 361 2.1.2. Prefix-SID Propagation 363 The Prefix-SID sub-TLV MUST be preserved when the IP Reachability TLV 364 gets propagated across level boundaries. 366 The level-1-2 router that propagates the Prefix-SID sub-TLV between 367 levels MUST set the R-flag. 369 If the Prefix-SID contains a global index (L and V flags unset) and 370 it is propagated as such (with L and V flags unset), the value of the 371 index MUST be preserved when propagated between levels. 373 The level-1-2 router that propagates the Prefix-SID sub-TLV between 374 levels MAY change the setting of the L and V flags in case a local 375 label value is encoded in the Prefix-SID instead of the received 376 value. 378 2.2. Adjacency Segment Identifier 380 A new IS-IS sub-TLV is defined: the Adjacency Segment Identifier sub- 381 TLV (Adj-SID sub-TLV). 383 The Adj-SID sub-TLV is an optional sub-TLV carrying the Segment 384 Routing IGP-Adjacency-SID as defined in 385 [I-D.ietf-spring-segment-routing] with flags and fields that may be 386 used, in future extensions of Segment Routing, for carrying other 387 types of SIDs. 389 IS-IS adjacencies are advertised using one of the IS-Neighbor TLVs 390 below: 392 TLV-22 [RFC5305] 394 TLV-222 [RFC5120] 396 TLV-23 [RFC5311] 398 TLV-223 [RFC5311] 400 TLV-141 [RFC5316] 402 Multiple Adj-SID sub-TLVs MAY be associated with a single IS- 403 neighbor. Examples where more than one Adj-SID may be used per IS- 404 neighbor are described in 405 [I-D.filsfils-spring-segment-routing-use-cases]. 407 2.2.1. Adjacency Segment Identifier (Adj-SID) Sub-TLV 409 The following format is defined for the Adj-SID sub-TLV: 411 0 1 2 3 412 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 1 413 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 414 | Type | Length | Flags | Weight | 415 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 416 | SID/Label/Index (variable) | 417 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 419 where: 421 Type: TBD, suggested value 31 423 Length: variable. 425 Flags: 1 octet field of following flags: 427 0 1 2 3 4 5 6 7 428 +-+-+-+-+-+-+-+-+ 429 |F|B|V|L|S| | 430 +-+-+-+-+-+-+-+-+ 432 where: 434 F-Flag: Address-Family flag. If unset, then the Adj-SID refers 435 to an adjacency with outgoing IPv4 encapsulation. If set then 436 the Adj-SID refers to an adjacency with outgoing IPv6 437 encapsulation. 439 B-Flag: Backup flag. If set, the Adj-SID is eligible for 440 protection (e.g.: using IPFRR or MPLS-FRR) as described in 441 [I-D.ietf-spring-resiliency-use-cases]. 443 V-Flag: Value flag. If set, then the Adj-SID carries a value. 444 By default the flag is SET. 446 L-Flag: Local Flag. If set, then the value/index carried by 447 the Adj-SID has local significance. By default the flag is 448 SET. 450 S-Flag. Set Flag. When set, the S-Flag indicates that the 451 Adj-SID refers to a set of adjacencies (and therefore MAY be 452 assigned to other adjacencies as well). 454 Other bits: MUST be zero when originated and ignored when 455 received. 457 Weight: 1 octet. The value represents the weight of the Adj-SID 458 for the purpose of load balancing. The use of the weight is 459 defined in [I-D.ietf-spring-segment-routing]. 461 SID/Index/Label: according to the V and L flags, it contains 462 either: 464 * A 3 octet local label where the 20 rightmost bits are used for 465 encoding the label value. In this case the V and L flags MUST 466 be set. 468 * A 4 octet index defining the offset in the SID/Label space 469 advertised by this router using the encodings defined in 470 Section 3.1. In this case V and L flags MUST be unset. 472 * A 16 octet IPv6 address. In this case the V flag MUST be set. 473 The L flag MUST be unset if the IPv6 address is globally 474 unique. 476 An SR capable router MAY allocate an Adj-SID for each of its 477 adjacencies and SHOULD set the B-Flag when the adjacency is 478 eligible for protection (IP or MPLS). 480 An SR capable router MAY allocate more than one Adj-SID to an 481 adjacency. 483 An SR capable router MAY allocate the same Adj-SID to different 484 adjacencies. 486 Examples of use of the Adj-SID sub-TLV are described in 487 [I-D.ietf-spring-segment-routing]. and 488 [I-D.previdi-6man-segment-routing-header]. 490 The F-flag is used in order for the router to advertise the 491 outgoing encapsulation of the adjacency the Adj-SID is attached 492 to. Use cases of the use of the F-flag are described in 493 [I-D.filsfils-spring-segment-routing-use-cases]. 495 2.2.2. Adjacency Segment Identifiers in LANs 497 In LAN subnetworks, the Designated Intermediate System (DIS) is 498 elected and originates the Pseudonode-LSP (PN-LSP) including all 499 neighbors of the DIS. 501 When Segment Routing is used, each router in the LAN MAY advertise 502 the Adj-SID of each of its neighbors. Since, on LANs, each router 503 only advertises one adjacency to the DIS (and doesn't advertise any 504 other adjacency), each router advertises the set of Adj-SIDs (for 505 each of its neighbors) inside a newly defined sub-TLV part of the TLV 506 advertising the adjacency to the DIS (e.g.: TLV-22). 508 The following new sub-TLV is defined: LAN-Adj-SID (Type: TBD, 509 suggested value 32) containing the set of Adj-SIDs the router 510 assigned to each of its LAN neighbors. 512 The format of the LAN-Adj-SID sub-TLV is as follows: 514 0 1 2 3 515 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 1 516 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 517 | Type | Length | Flags | Weight | 518 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 520 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 521 | System-ID (6 octets) | 522 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 523 | | 524 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 526 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 527 | SID/Label/Index (variable) | 528 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 530 where: 532 Type: TBD, suggested value 32 534 Length: variable. 536 Flags: 1 octet field of following flags: 538 0 1 2 3 4 5 6 7 539 +-+-+-+-+-+-+-+-+ 540 |F|B|V|L|S| | 541 +-+-+-+-+-+-+-+-+ 543 where F, B, V, L and S flags are defined in Section 2.2.1. Other 544 bits: MUST be zero when originated and ignored when received. 546 Weight: 1 octet. The value represents the weight of the Adj-SID 547 for the purpose of load balancing. The use of the weight is 548 defined in [I-D.ietf-spring-segment-routing]. 550 System-ID: 6 octets of IS-IS System-ID of length "ID Length" as 551 defined in [ISO10589]. 553 SID/Index/Label: according to the V and L flags, it contains 554 either: 556 * A 3 octet local label where the 20 rightmost bits are used for 557 encoding the label value. In this case the V and L flags MUST 558 be set. 560 * A 4 octet index defining the offset in the SID/Label space 561 advertised by this router using the encodings defined in 562 Section 3.1. In this case V and L flags MUST be unset. 564 * A 16 octet IPv6 address. In this case the V flag MUST be set. 565 The L flag MUST be unset if the IPv6 address is globally 566 unique. 568 Multiple LAN-Adj-SID sub-TLVs MAY be encoded. 570 In case one TLV-22/23/222/223 (reporting the adjacency to the DIS) 571 can't contain the whole set of LAN-Adj-SID sub-TLVs, multiple 572 advertisements of the adjacency to the DIS MUST be used and all 573 advertisements MUST have the same metric. 575 Each router within the level, by receiving the DIS PN LSP as well as 576 the non-PN LSP of each router in the LAN, is capable of 577 reconstructing the LAN topology as well as the set of Adj-SID each 578 router uses for each of its neighbors. 580 A label is encoded in 3 octets (in the 20 rightmost bits). 582 An index is encoded in 4 octets. 584 An ipv6 address SID is encoded in 16 octets (IPv6 Adj-SID is defined 585 in [I-D.previdi-6man-segment-routing-header]). 587 2.3. SID/Label Sub-TLV 589 The SID/Label sub-TLV is present in the following sub-TLVs defined in 590 this document: 592 Binding TLV Section 2.4. 594 SR Capability sub-TLV Section 3.1. 596 The SID/Label sub-TLV contains a SID or a MPLS Label. The SID/Label 597 sub-TLV has the following format: 599 0 1 2 3 600 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 1 601 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 602 | Type | Length | 603 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 604 | SID/Label (variable) | 605 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 607 where: 609 Type: TBD, suggested value 1 611 Length: variable 613 SID/Label: if length is set to 3 then the 20 rightmost bits 614 represent a MPLS label. 616 2.4. SID/Label Binding TLV 618 The SID/Label Binding TLV MAY be originated by any router in an IS-IS 619 domain. There are multiple uses of the SID/Label Binding TLV: 621 o The router may advertise a SID/Label binding to a FEC along with 622 at least a single 'nexthop style' anchor. The protocol supports 623 more than one 'nexthop style' anchor to be attached to a SID/Label 624 binding, which results into a simple path description language. 625 In analogy to RSVP the terminology for this is called an 'Explicit 626 Route Object' (ERO). Since ERO style path notation allows to 627 anchor SID/label bindings to both link and node IP addresses any 628 label switched path, can be described. Furthermore also SID/Label 629 Bindings from external protocols can get easily re-advertised. 631 o The SID/Label Binding TLV may be used for advertising SID/Label 632 Bindings and their associated Primary and Backup paths. In one 633 single TLV either a primary ERO Path, a backup ERO Path or both 634 are advertised. If a router wants to advertise multiple parallel 635 paths then it can generate several TLVs for the same Prefix/FEC. 636 Each occurrence of a Binding TLV with respect with a given FEC 637 Prefix has accumulating and not canceling semantics. Due the 638 space constraints in the 8-Bit IS-IS TLVs an originating router 639 MAY encode a primary ERO path in one SID/Label Binding TLV and the 640 backup ERO path in a second SID/Label Binding TLV. Note that the 641 FEC Prefix and SID/Label sub-TLV MUST be identical in both TLVs. 643 o The SID/Label Binding TLV may also be used in order to advertise 644 prefixes to SID/Label mappings. This functionality is called the 645 'Mapping Server' and it's used when, in a heterogeneous network, 646 not all nodes are capable of advertising their own SIDs/Labels. 647 When the SID/Label Binding TLV is used by the Mapping Server in 648 order to advertise prefix to SID/label mappings, the index/label 649 MUST include the Prefix-SID SubTLV (Section 2.1). 651 The SID/Label Binding TLV has Type TBD (suggested value 149), and has 652 the following format: 654 0 1 2 3 655 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 1 656 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 657 | Type | Length | Flags | Weight | 658 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 659 | Range | Prefix Length | FEC Prefix | 660 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 661 // FEC Prefix (continued, variable) // 662 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 663 | SubTLVs (variable) | 664 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 666 Figure 1: SID/Label Binding TLV format 668 o Type: TBD, suggested value 149 670 o Length: variable. 672 o 1 octet of flags 674 o 1 octet of Weight 676 o 2 octets of Range 678 o 1 octet of Prefix Length 680 o 0-16 octets of FEC Prefix 682 o sub-TLVs, where each sub-TLV consists of a sequence of: 684 * 1 octet of sub-TLV type 686 * 1 octet of length of the value field of the sub-TLV 688 * 0-243 octets of value 690 2.4.1. Flags 692 Flags: 1 octet field of following flags: 694 0 1 2 3 4 5 6 7 695 +-+-+-+-+-+-+-+-+ 696 |F|M|S|D|A| | 697 +-+-+-+-+-+-+-+-+ 699 where: 701 F-Flag: Address Family flag. If unset, then the Prefix FEC 702 carries an IPv4 Prefix. If set then the Prefix FEC carries an 703 IPv6 Prefix. 705 M-Flag: Mirror Context flag. Set if the advertised SID/path 706 corresponds to a mirrored context. The use of the M flag is 707 described in [I-D.ietf-spring-segment-routing]. 709 S-Flag: If set, the SID/Label Binding TLV SHOULD be flooded across 710 the entire routing domain. If the S flag is not set, the SID/ 711 Label Binding TLV MUST NOT be leaked between levels. This bit 712 MUST NOT be altered during the TLV leaking. 714 D-Flag: when the SID/Label Binding TLV is leaked from level-2 to 715 level-1, the D bit MUST be set. Otherwise, this bit MUST be 716 clear. SID/Label Binding TLVs with the D bit set MUST NOT be 717 leaked from level-1 to level-2. This is to prevent TLV looping 718 across levels. 720 A-Flag: Attached flag. The originator of the SID/Label Binding 721 TLV MAY set the A bit in order to signal that the prefixes and 722 SIDs advertised in the SID/Label Binding TLV are directly 723 connected to their originators. The mechanisms through which the 724 originator of the SID/Label Binding TLV can figure out if a prefix 725 is attached or not are outside the scope of this document (e.g.: 726 through explicit configuration). 728 An implementation MAY decide not to honor the S-flag in order not 729 to leak Binding TLV's between levels (for policy reasons). In all 730 cases, the D flag MUST always be set by any router leaking the 731 Binding TLV from level-2 into level-1 and MUST be checked when 732 propagating the Binding TLV from level-1 into level-2. If the D 733 flag is set, the Binding TLV MUST NOT be propagated into level-2. 735 Other bits: MUST be zero when originated and ignored when 736 received. 738 2.4.2. Weight 740 Weight: 1 octet: The value represents the weight of the path for the 741 purpose of load balancing. The use of the weight is defined in 742 [I-D.ietf-spring-segment-routing]. 744 2.4.3. Range 746 The 'Range' field provides the ability to specify a range of 747 addresses and their associated Prefix SIDs. This functionality is 748 called "Mapping Server". It is essentially a compression scheme to 749 distribute a continuous Prefix and their continuous, corresponding 750 SID/Label Block. If a single SID is advertised then the range field 751 MUST be set to one. For range advertisements > 1, the number of 752 addresses that need to be mapped into a Prefix-SID and the starting 753 value of the Prefix-SID range. 755 Example 1: if the following router addresses (loopback addresses) 756 need to be mapped into the corresponding Prefix SID indexes. 758 Router-A: 192.0.2.1/32, Prefix-SID: Index 1 759 Router-B: 192.0.2.2/32, Prefix-SID: Index 2 760 Router-C: 192.0.2.3/32, Prefix-SID: Index 3 761 Router-D: 192.0.2.4/32, Prefix-SID: Index 4 763 0 1 2 3 764 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 1 765 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 766 | Type | Length |0|0| | Weight | 767 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 768 | Range = 4 | /32 | 192 | 769 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 770 | .0 | .2 | .1 |Prefix-SID Type| 771 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 772 | sub-TLV Length| Flags | Algorithm | | 773 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 774 | 1 | 775 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 777 Example-2: If the following prefixes need to be mapped into the 778 corresponding Prefix-SID indexes: 780 10.1.1/24, Prefix-SID: Index 51 781 10.1.2/24, Prefix-SID: Index 52 782 10.1.3/24, Prefix-SID: Index 53 783 10.1.4/24, Prefix-SID: Index 54 784 10.1.5/24, Prefix-SID: Index 55 785 10.1.6/24, Prefix-SID: Index 56 786 10.1.7/24, Prefix-SID: Index 57 787 0 1 2 3 788 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 1 789 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 790 | Type | Length |0|0| | Weight | 791 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 792 | Range = 7 | /24 | 10 | 793 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 794 | .1 | .1 |Prefix-SID Type| sub-TLV Length| 795 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 796 | Flags | Algorithm | | 797 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 798 | 51 | 799 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 801 It is not expected that a network operator will be able to keep fully 802 continuous FEC Prefix / SID/Index mappings. In order to support 803 noncontinuous mapping ranges an implementation MAY generate several 804 instances of Binding TLVs. 806 For example if a router wants to advertise the following ranges: 808 Range 16: { 192.168.1.1-15, Index 1-15 } 810 Range 6: { 192.168.1.22-27, Index 22-27 } 812 Range 41: { 192.168.1.44-84, Index 80-120 } 814 A router would need to advertise three instances of the Binding TLV. 816 2.4.4. Prefix Length, Prefix 818 The 'FEC Prefix' represents the Forwarding equivalence class at the 819 tail-end of the advertised path. The 'FEC Prefix' does not need to 820 correspond to a routable prefix of the originating node. 822 The 'Prefix Length' field contains the length of the prefix in bits. 823 Only the most significant octets of the Prefix FEC are encoded. I.e. 824 1 octet for FEC prefix length 1 up to 8, 2 octets for FEC prefix 825 length 9 to 16, 3 octets for FEC prefix length 17 up to 24 and 4 826 octets for FEC prefix length 25 up to 32, ...., 16 octets for FEC 827 prefix length 113 up to 128. 829 2.4.5. Mapping Server Prefix-SID 831 The Prefix-SID sub-TLV (suggested value 3) is defined in Section 2.1 832 and contains the SID/index/label value associated with the prefix and 833 range. The Prefix-SID SubTLV MUST be used when the SID/Label Binding 834 TLV is used by the Mapping Server (i.e.: advertising one or a range 835 of prefixes and their associated SIDs/Labels). 837 A node receiving a MS entry for a prefix MUST check the existence of 838 such prefix in its link-state database prior to consider and use the 839 associated SID. 841 For a given prefix, if both a MS entry with its Prefix-SID Sub-TLV 842 and a Prefix TLV (e.g.: TLV135) with its Prefix-SID are received, the 843 Prefix-SID advertised within the Prefix TLV MUST be preferred while 844 the MS entry MUST be ignored. 846 2.4.5.1. Prefix-SID Flags 848 The Prefix-SID flags are defined in Section 2.1. The Mapping Server 849 MAY advertise a mapping with the N flag set when the prefix being 850 mapped is known in the link-state topology with a mask length of 32 851 (IPv4) or 128 (IPv6) and when the prefix represents a node. The 852 mechanisms through which the operator defines that a prefix 853 represents a node are outside the scope of this document (typically 854 it will be through configuration). 856 The other flags defined in Section 2.1 are not used by the Mapping 857 Server and MUST be ignored at reception. 859 2.4.5.2. Prefix-SID Algorithm 861 The algorithm field contains the identifier of the algorithm the 862 router MUST use in order to compute reachability to the range of 863 prefixes. Use of the algorithm field is described in Section 2.1. 865 2.4.6. SID/Label Sub-TLV 867 The SID/Label sub-TLV (Type: TBD, suggested value 1) contains the 868 SID/Label value as defined in Section 2.3. It MAY be present in the 869 SID/Label Binding TLV. 871 2.4.7. ERO Metric sub-TLV 873 ERO Metric sub-TLV (Type: TBD, suggested value 10) is a sub-TLV of 874 the SID/Label Binding TLV. 876 The ERO Metric sub-TLV carries the cost of an ERO path. It is used 877 to compare the cost of a given source/destination path. A router MAY 878 advertise the ERO Metric sub-TLV. The cost of the ERO Metric sub-TLV 879 SHOULD be set to the cumulative IGP or TE path cost of the advertised 880 ERO. Since manipulation of the Metric field may attract or distract 881 traffic from and to the advertised segment it MAY be manually 882 overridden. 884 0 1 2 3 885 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 1 886 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 887 | Type | Length | Metric | 888 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 889 | Metric (continued) | 890 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 892 ERO Metric sub-TLV format 894 where: 896 Type: TBD, suggested value 10 898 Length: 4 900 Metric: 4 bytes 902 2.4.8. IPv4 ERO subTLV 904 The IPv4 ERO subTLV (Type: TBD, suggested value 11) describes a path 905 segment using IPv4 address style of encoding. Its semantics have 906 been borrowed from [RFC3209]. 908 The 'L' bit in the Flags is a one-bit attribute. If the L bit is 909 set, then the value of the attribute is 'loose.' Otherwise, the 910 value of the attribute is 'strict.' 912 0 1 2 3 913 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 1 914 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 915 | Type | Length |L| Reserved | IPv4 address | 916 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 917 | IPv4 address (continued) | 918 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 920 Figure 2: IPv4 ERO subTLV format 922 2.4.9. IPv6 ERO subTLV 924 The IPv6 ERO subTLV (Type: TBD, suggested value 12) describes a path 925 segment using IPv6 Address style of encoding. Its semantics have 926 been borrowed from [RFC3209]. 928 The 'L' bit in the Flags is a one-bit attribute. If the L bit is 929 set, then the value of the attribute is 'loose.' Otherwise, the 930 value of the attribute is 'strict.' 932 0 1 2 3 933 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 1 934 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 935 | Type | Length |L| Reserved | IPv6 address | 936 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 937 | IPv6 Address (continued) | 938 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 939 | IPv6 Address (continued) | 940 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 941 | IPv6 Address (continued) | 942 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 943 | IPv6 Address (continued) | 944 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 946 Figure 3: IPv6 ERO subTLV format 948 2.4.10. Unnumbered Interface ID ERO subTLV 950 The appearance and semantics of the 'Unnumbered Interface ID' have 951 been borrowed from Section 4 [RFC3477]. 953 The Unnumbered Interface-ID ERO subTLV (Type: TBD, suggested value 954 13) describes a path segment that spans over an unnumbered interface. 955 Unnumbered interfaces are referenced using the interface index. 956 Interface indices are assigned local to the router and therefore not 957 unique within a domain. All elements in an ERO path need to be 958 unique within a domain and hence need to be disambiguated using a 959 domain unique Router-ID. 961 The 'Router-ID' field contains the router ID of the router which has 962 assigned the 'Interface ID' field. Its purpose is to disambiguate 963 the 'Interface ID' field from other routers in the domain. 965 IS-IS supports two Router-ID formats: 967 o (TLV 134, 32-Bit format) [RFC5305] 969 o (TLV 140, 128-Bit format) [RFC6119] 971 The actual Router-ID format gets derived from the 'Length' field. 973 o For 32-Bit Router-ID width the subTLV length is set to 8 octets. 975 o For 128-Bit Router-ID width the subTLV length is set to 20 octets. 977 The 'Interface ID' is the identifier assigned to the link by the 978 router specified by the router ID. 980 The 'L' bit in the Flags is a one-bit attribute. If the L bit is 981 set, then the value of the attribute is 'loose.' Otherwise, the 982 value of the attribute is 'strict.' 984 0 1 2 3 985 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 1 986 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 987 | Type | Length |L| Reserved | 988 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 989 // Router ID (32 or 128 bits) // 990 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 991 | Interface ID (32 bits) | 992 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 994 Figure 4: Unnumbered Interface ID ERO subTLV format 996 2.4.11. IPv4 Backup ERO subTLV 998 The IPv4 Backup ERO subTLV (Type: TBD, suggested value 14) describes 999 a Backup path segment using IPv4 Address style of encoding. Its 1000 appearance and semantics have been borrowed from [RFC3209]. 1002 The 'L' bit in the Flags is a one-bit attribute. If the L bit is 1003 set, then the value of the attribute is 'loose.' Otherwise, the 1004 value of the attribute is 'strict.' 1006 0 1 2 3 1007 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 1008 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1009 | Type | Length |L| Reserved | IPv4 address | 1010 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1011 | IPv4 address (continued) | 1012 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1014 Figure 5: IPv4 Backup ERO subTLV format 1016 2.4.12. IPv6 Backup ERO subTLV 1018 The IPv6 Backup ERO subTLV (Type: TBD, suggested value 15) describes 1019 a Backup path segment using IPv6 Address style of encoding. Its 1020 appearance and semantics have been borrowed from [RFC3209]. 1022 The 'L' bit in the Flags is a one-bit attribute. If the L bit is 1023 set, then the value of the attribute is 'loose.' Otherwise, the 1024 value of the attribute is 'strict.' 1025 0 1 2 3 1026 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 1027 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1028 | Type | Length |L| Reserved | IPv6 address | 1029 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1030 | IPv6 Address (continued) | 1031 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1032 | IPv6 Address (continued) | 1033 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1034 | IPv6 Address (continued) | 1035 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1036 | IPv6 Address (continued) | 1037 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1039 Figure 6: IPv6 Backup ERO subTLV format 1041 2.4.13. Unnumbered Interface ID Backup ERO subTLV 1043 The appearance and semantics of the 'Unnumbered Interface ID' have 1044 been borrowed from Section 4 [RFC3477]. 1046 The Unnumbered Interface-ID Backup ERO subTLV (Type: TBD, suggested 1047 value 16) describes a Backup LSP path segment that spans over an 1048 unnumbered interface. Unnumbered interfaces are referenced using the 1049 interface index. Interface indices are assigned local to the router 1050 and therefore not unique within a domain. All elements in an ERO 1051 path need to be unique within a domain and hence need to be 1052 disambiguated using a domain unique Router-ID. 1054 The 'Router-ID' field contains the router ID of the router which has 1055 assigned the 'Interface ID' field. Its purpose is to disambiguate 1056 the 'Interface ID' field from other routers in the domain. 1058 IS-IS supports two Router-ID formats: 1060 o (TLV 134, 32-Bit format) [RFC5305] 1062 o (TLV 140, 128-Bit format) [RFC6119] 1064 The actual Router-ID format gets derived from the 'Length' field. 1066 o For 32-Bit Router-ID width the subTLV length is set to 8 octets. 1068 o For 128-Bit Router-ID width the subTLV length is set to 20 octets. 1070 The 'Interface ID' is the identifier assigned to the link by the 1071 router specified by the router ID. 1073 The 'L' bit in the Flags is a one-bit attribute. If the L bit is 1074 set, then the value of the attribute is 'loose.' Otherwise, the 1075 value of the attribute is 'strict.' 1077 0 1 2 3 1078 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 1079 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1080 | Type | Length |L| Reserved | 1081 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1082 // Router ID (32 or 128 bits) // 1083 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1084 | Interface ID (32 bits) | 1085 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1087 Figure 7: Unnumbered Interface ID Backup ERO subTLV format 1089 2.4.14. Prefix ERO and Prefix Backup ERO subTLV path semantics 1091 All 'ERO' and 'Backup ERO' information represents an ordered set 1092 which describes the segments of a path. The last ERO subTLV 1093 describes the segment closest to the egress point of the path. 1094 Contrary the first ERO subTLV describes the first segment of a path. 1095 If a router extends or stitches a label switched path it MUST prepend 1096 the new segments path information to the ERO list. The same ordering 1097 applies for the Backup ERO labels. An implementation SHOULD first 1098 encode all primary path EROs followed by the bypass EROs. 1100 2.5. Multi-Topology SID/Label Binding TLV 1102 The Multi-Topology SID/Label Binding TLV allows the support of M-ISIS 1103 as defined in [RFC5120]. The Multi-Topology SID/Label Binding TLV 1104 has the same format as the SID/Label Binding TLV defined in 1105 Section 2.4 with the difference consisting of a Multitopology 1106 Identifier (MTID) as defined here below: 1108 0 1 2 3 1109 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 1110 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1111 | Type | Length | MTID | 1112 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1113 | Flags | Weight | Range | 1114 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1115 | Prefix Length | FEC Prefix | FEC Prefix (variable) | 1116 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1117 | SubTLVs (variable) | 1118 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1120 Figure 8: Multi-Topology SID/Label Binding TLV format 1122 where: 1124 Type: TBD, suggested value 150 1126 Length: variable 1128 MTID is the multitopology identifier defined as: 1130 0 1 1131 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 1132 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1133 | RESVD | MTID | 1134 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1136 RESVD: reserved bits. MUST be reset on transmission and 1137 ignored on receive. 1139 MTID: a 12-bit field containing the non-zero ID of the topology 1140 being announced. The TLV MUST be ignored if the ID is zero. 1141 This is to ensure the consistent view of the standard unicast 1142 topology. 1144 The other fields and SubTLVs are defined in Section 2.4. 1146 3. Router Capabilities 1148 3.1. SR-Capabilities Sub-TLV 1150 Segment Routing requires each router to advertise its SR data-plane 1151 capability and the range of MPLS label values it uses for Segment 1152 Routing in the case where global SIDs are allocated (i.e.: global 1153 indexes). Data-plane capabilities and label ranges are advertised 1154 using the newly defined SR-Capabilities sub-TLV inserted into the IS- 1155 IS Router Capability TLV-242 that is defined in [RFC4971]. 1157 The Router Capability TLV specifies flags that control its 1158 advertisement. The SR Capabilities sub-TLV MUST be propagated 1159 throughout the level and SHOULD NOT be advertised across level 1160 boundaries. Therefore Router Capability TLV distribution flags 1161 SHOULD be set accordingly, i.e.: the S flag MUST be unset. 1163 The SR Capabilities sub-TLV has following format: 1165 0 1 2 3 1166 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 1167 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1168 | Type | Length | Flags | 1169 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1170 Type: TBD, suggested value 2 1172 Length: variable. 1174 Flags: 1 octet of flags. The following are defined: 1176 0 1 2 3 4 5 6 7 1177 +-+-+-+-+-+-+-+-+ 1178 |I|V| | 1179 +-+-+-+-+-+-+-+-+ 1181 where: 1183 I-Flag: IPv4 flag. If set, then the router is capable of 1184 outgoing IPv4 encapsulation on all interfaces. 1186 V-Flag: IPv6 flag. If set, then the router is capable of 1187 outgoing IPv6 encapsulation on all interfaces. 1189 One or more SRGB Descriptor entries, each of which have the 1190 following format: 1192 Range: 3 octets. 1194 SID/Label sub-TLV (as defined in Section 2.3). 1196 SID/Label sub-TLV contains the first value of the SRGB while the 1197 range contains the number of SRGB elements. The range value MUST be 1198 higher than 0. 1200 The SR-Capabilities sub-TLV MAY be advertised in an LSP of any number 1201 but a router MUST NOT advertise more than one SR-Capabilities sub- 1202 TLV. When multiple SR-Capabilities sub-TLVs are received from a 1203 given router the behavior of the receiving system is undefined. 1205 When multiple SRGB Descriptors are advertised the entries define an 1206 ordered set of ranges on which a SID index is to be applied. For 1207 this reason changing the order in which the descriptors are 1208 advertised will have a disruptive effect on forwarding. 1210 When a router adds a new SRGB Descriptor to an existing SR- 1211 Capabilities sub-TLV the new Descriptor SHOULD add the newly 1212 configured block at the end of the sub-TLV and SHOULD NOT change the 1213 order of previously advertised blocks. Changing the order of the 1214 advertised descriptors will create label churn in the FIB and 1215 blackhole / misdirect some traffic during the IGP convergence. In 1216 particular, if a range which is not the last is extended it's 1217 preferable to add a new range rather than extending the previously 1218 advertised range. 1220 The originating router MUST NOT advertise overlapping ranges. 1222 Here follows an example of advertisement of multiple ranges: 1224 The originating router advertises following ranges: 1225 SR-Cap: range: 100, SID value: 100 1226 SR-Cap: range: 100, SID value: 1000 1227 SR-Cap: range: 100, SID value: 500 1229 The receiving routers concatenate the ranges in the received 1230 order and build the SRGB as follows: 1232 SRGB = [100, 199] 1233 [1000, 1099] 1234 [500, 599] 1236 The indexes span multiple ranges: 1238 index=0 means label 100 1239 ... 1240 index 99 means label 199 1241 index 100 means label 1000 1242 index 199 means label 1099 1243 ... 1244 index 200 means label 500 1245 ... 1247 3.2. SR-Algorithm Sub-TLV 1249 The router may use various algorithms when calculating reachability 1250 to other nodes or to prefixes attached to these nodes. Examples of 1251 these algorithms are metric based Shortest Path First (SPF), various 1252 sorts of Constrained SPF, etc. The SR-Algorithm sub-TLV (Type: TBD, 1253 suggested value 19) allows the router to advertise the algorithms 1254 that the router is currently using. The following value has been 1255 defined: 1257 0: Shortest Path First (SPF) algorithm based on link metric. 1259 The SR-Algorithm sub-TLV is inserted into the IS-IS Router Capability 1260 TLV-242 that is defined in [RFC4971]. 1262 The Router Capability TLV specifies flags that control its 1263 advertisement. The SR-Algorithm MUST be propagated throughout the 1264 level and need not to be advertised across level boundaries. 1266 Therefore Router Capability TLV distribution flags MUST be set 1267 accordingly, i.e.: the S flag MUST be unset. 1269 The SR-Algorithm sub-TLV is optional, it MAY only appear a single 1270 time inside the Router Capability TLV. 1272 When the originating router does not advertise the SR-Algorithm sub- 1273 TLV, then all the Prefix-SID advertised by the router MUST have 1274 algorithm field set to 0. Any receiving router MUST assume SPF 1275 algorithm (i.e.: Shortest Path First). 1277 The SR-Algorithm sub-TLV has following format: 1279 0 1 2 3 1280 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 1281 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1282 | Type | Length | 1283 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1284 | Algorithm 1 | Algorithm 2 | Algorithm ... | Algorithm n | 1285 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1287 where: 1289 Type: TBD, suggested value 19 1291 Length: variable. 1293 Algorithm: 1 octet of algorithm Section 2.1 1295 4. Non backward compatible changes with prior versions of this document 1297 This section describes the changes that have been applied to this 1298 document that are not backward compatible with previous versions. 1300 4.1. Encoding of Multiple SRGBs 1302 Version -04 of this document introduced a change in Section 3.1 1303 regarding the encoding method for multiple SRGBs in the SR-Cap SubTLV 1304 and made the support of multiple SRGBs REQUIRED. 1306 The modified method consists of having a single SR-Cap Sub-TLV where 1307 all SRGBs are encoded. In previous versions (prior to version -04) 1308 of this document it was allowed to have multiple occurrences of the 1309 SR-Cap Sub-TLV. 1311 At the time of writing this document, no existing implementations are 1312 affected by the change since no implementations actually (i.e.: at 1313 the time of updating this document) encode multiple SRGBs anyway. 1315 5. IANA Considerations 1317 This documents request allocation for the following TLVs and subTLVs. 1319 5.1. Sub TLVs for Type 22,23,222 and 223 1321 This document makes the following registrations in the "sub-TLVs for 1322 TLV 22, 23, 222 and 223" registry. 1324 Type: TBD (suggested value 31) 1326 Description: Adjacency Segment Identifier 1328 TLV 22: yes 1330 TLV 23: yes 1332 TLV 222: yes 1334 TLV 223: yes 1336 Reference: This document (Section 2.2.1) 1338 Type: TBD (suggested value 32) 1340 Description: LAN Adjacency Segment Identifier 1342 TLV 22: yes 1344 TLV 23: yes 1346 TLV 222: yes 1348 TLV 223: yes 1350 Reference: This document (Section 2.2.2) 1352 5.2. Sub TLVs for Type 135,235,236 and 237 1354 This document makes the following registrations in the "sub-TLVs for 1355 TLV 135,235,236 and 237" registry. 1357 Type: TBD (suggested value 3) 1358 Description: Prefix Segment Identifier 1360 TLV 135: yes 1362 TLV 235: yes 1364 TLV 236: yes 1366 TLV 237: yes 1368 Reference: This document (Section 2.1) 1370 5.3. Sub TLVs for Type 242 1372 This document makes the following registrations in the "sub-TLVs for 1373 TLV 242" registry. 1375 Type: TBD (suggested value 2) 1377 Description: Segment Routing Capability 1379 Reference: This document (Section 3.1) 1381 Type: TBD (suggested value 19) 1383 Description: Segment Routing Algorithm 1385 Reference: This document (Section 3.2) 1387 5.4. New TLV Codepoint and Sub-TLV registry 1389 This document registers the following TLV: 1391 Type: TBD (suggested value 149) 1393 name: Segment Identifier / Label Binding 1395 IIH: no 1397 LSP: yes 1399 SNP: no 1401 Purge: no 1402 Reference: This document (Section 2.4) 1404 Type: TBD (suggested value 150) 1406 name: Multi-Topology Segment Identifier / Label Binding 1408 IIH: no 1410 LSP: yes 1412 SNP: no 1414 Purge: no 1416 Reference: This document (Section 2.5) 1418 This document creates the following sub-TLV Registry: 1420 Registry: sub-TLVs for TLV 149 and 150 1422 Registration Procedure: Expert review 1424 Reference: This document (Section 2.4) 1426 Type: TBD, suggested value 1 1428 Description: SID/Label 1430 Reference: This document (Section 2.3) 1432 Type: TBD, suggested value 3 1434 Description: Prefix-SID 1436 Reference: This document (Section 2.1) 1438 Type: TBD, suggested value 10 1440 Description: ERO Metric 1442 Reference: This document (Section 2.4.7) 1443 Type: TBD, suggested value 11 1445 Description: IPv4 ERO 1447 Reference: This document (Section 2.4.8) 1449 Type: TBD, suggested value 12 1451 Description: IPv6 ERO 1453 Reference: This document (Section 2.4.9) 1455 Type: TBD, suggested value 13 1457 Description: Unnumbered Interface-ID ERO 1459 Reference: This document (Section 2.4.10) 1461 Type: TBD, suggested value 14 1463 Description: IPv4 Backup ERO 1465 Reference: This document (Section 2.4.11) 1467 Type: TBD, suggested value 15 1469 Description: IPv6 Backup ERO 1471 Reference: This document (Section 2.4.12) 1473 Type: TBD, suggested value 16 1475 Description: Unnumbered Interface-ID Backup ERO 1477 Reference: This document (Section 2.4.13) 1479 6. Manageability Considerations 1481 TBD 1483 7. Security Considerations 1485 TBD 1487 8. Contributors 1489 The following people gave a substantial contribution to the content 1490 of this document: Les Ginsberg, Martin Horneffer, Igor Milojevic, Rob 1491 Shakir, Saku Ytti, Wim Henderickx, Steven Luong and Jesper Skriver. 1493 9. Acknowledgements 1495 We would like to thank Dave Ward, Dan Frost, Stewart Bryant and 1496 Pierre Francois for their contribution to the content of this 1497 document. 1499 Many thanks to Yakov Rekhter and Ina Minei for their contribution on 1500 earlier incarnations of the "Binding / MPLS Label TLV". 1502 10. References 1504 10.1. Normative References 1506 [I-D.ginsberg-isis-prefix-attributes] 1507 Ginsberg, L., Decraene, B., Filsfils, C., Litkowski, S., 1508 and S. Previdi, "IS-IS Prefix Attributes for Extended IP 1509 and IPv6 Reachability", draft-ginsberg-isis-prefix- 1510 attributes-01 (work in progress), March 2015. 1512 [I-D.ietf-spring-segment-routing] 1513 Filsfils, C., Previdi, S., Bashandy, A., Decraene, B., 1514 Litkowski, S., Horneffer, M., Shakir, R., Tantsura, J., 1515 and E. Crabbe, "Segment Routing Architecture", draft-ietf- 1516 spring-segment-routing-01 (work in progress), February 1517 2015. 1519 [ISO10589] 1520 International Organization for Standardization, 1521 "Intermediate system to Intermediate system intra-domain 1522 routeing information exchange protocol for use in 1523 conjunction with the protocol for providing the 1524 connectionless-mode Network Service (ISO 8473)", ISO/IEC 1525 10589:2002, Second Edition, Nov 2002. 1527 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1528 Requirement Levels", BCP 14, RFC 2119, March 1997. 1530 [RFC4971] Vasseur, JP., Shen, N., and R. Aggarwal, "Intermediate 1531 System to Intermediate System (IS-IS) Extensions for 1532 Advertising Router Information", RFC 4971, July 2007. 1534 [RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi 1535 Topology (MT) Routing in Intermediate System to 1536 Intermediate Systems (IS-ISs)", RFC 5120, February 2008. 1538 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic 1539 Engineering", RFC 5305, October 2008. 1541 [RFC5308] Hopps, C., "Routing IPv6 with IS-IS", RFC 5308, October 1542 2008. 1544 [RFC6119] Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic 1545 Engineering in IS-IS", RFC 6119, February 2011. 1547 10.2. Informative References 1549 [I-D.filsfils-spring-segment-routing-use-cases] 1550 Filsfils, C., Francois, P., Previdi, S., Decraene, B., 1551 Litkowski, S., Horneffer, M., Milojevic, I., Shakir, R., 1552 Ytti, S., Henderickx, W., Tantsura, J., Kini, S., and E. 1553 Crabbe, "Segment Routing Use Cases", draft-filsfils- 1554 spring-segment-routing-use-cases-01 (work in progress), 1555 October 2014. 1557 [I-D.ietf-spring-resiliency-use-cases] 1558 Francois, P., Filsfils, C., Decraene, B., and R. Shakir, 1559 "Use-cases for Resiliency in SPRING", draft-ietf-spring- 1560 resiliency-use-cases-01 (work in progress), March 2015. 1562 [I-D.previdi-6man-segment-routing-header] 1563 Previdi, S., Filsfils, C., Field, B., and I. Leung, "IPv6 1564 Segment Routing Header (SRH)", draft-previdi-6man-segment- 1565 routing-header-06 (work in progress), May 2015. 1567 [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., 1568 and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP 1569 Tunnels", RFC 3209, December 2001. 1571 [RFC3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links 1572 in Resource ReSerVation Protocol - Traffic Engineering 1573 (RSVP-TE)", RFC 3477, January 2003. 1575 [RFC5311] McPherson, D., Ginsberg, L., Previdi, S., and M. Shand, 1576 "Simplified Extension of Link State PDU (LSP) Space for 1577 IS-IS", RFC 5311, February 2009. 1579 [RFC5316] Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in 1580 Support of Inter-Autonomous System (AS) MPLS and GMPLS 1581 Traffic Engineering", RFC 5316, December 2008. 1583 Authors' Addresses 1585 Stefano Previdi (editor) 1586 Cisco Systems, Inc. 1587 Via Del Serafico, 200 1588 Rome 00142 1589 Italy 1591 Email: sprevidi@cisco.com 1593 Clarence Filsfils 1594 Cisco Systems, Inc. 1595 Brussels 1596 BE 1598 Email: cfilsfil@cisco.com 1600 Ahmed Bashandy 1601 Cisco Systems, Inc. 1602 170, West Tasman Drive 1603 San Jose, CA 95134 1604 US 1606 Email: bashandy@cisco.com 1608 Hannes Gredler 1609 Juniper Networks, Inc. 1610 1194 N. Mathilda Ave. 1611 Sunnyvale, CA 94089 1612 US 1614 Email: hannes@juniper.net 1615 Stephane Litkowski 1616 Orange 1617 FR 1619 Email: stephane.litkowski@orange.com 1621 Bruno Decraene 1622 Orange 1623 FR 1625 Email: bruno.decraene@orange.com 1627 Jeff Tantsura 1628 Ericsson 1629 300 Holger Way 1630 San Jose, CA 95134 1631 US 1633 Email: Jeff.Tantsura@ericsson.com