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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 LSR Working Group U. Chunduri 3 Internet-Draft Y. Qu 4 Intended status: Standards Track Huawei USA 5 Expires: September 25, 2018 J. Tantsura 6 Nuage Networks 7 March 24, 2018 9 Usage of Non Shortest Path Forwarding (NSPF) IDs in OSPF 10 draft-ct-ospf-nspfid-for-sr-paths-00 12 Abstract 14 This document specifies the advertisement of Non Shortest Path 15 Forwarding IDentifier (NSPF ID) TLV and the computation procedures 16 for the same in OSPFv2 and OSPFv3 protocols. NSPF ID allows to 17 simplify the data plane path description of data traffic in SR 18 deployments. This helps to mitigate the MTU issues that are caused 19 by additional SR overhead of the packet and allows traffic 20 statistics. 22 Requirements Language 24 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 25 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 26 document are to be interpreted as described in RFC2119 [RFC2119]. 28 Status of This Memo 30 This Internet-Draft is submitted in full conformance with the 31 provisions of BCP 78 and BCP 79. 33 Internet-Drafts are working documents of the Internet Engineering 34 Task Force (IETF). Note that other groups may also distribute 35 working documents as Internet-Drafts. The list of current Internet- 36 Drafts is at https://datatracker.ietf.org/drafts/current/. 38 Internet-Drafts are draft documents valid for a maximum of six months 39 and may be updated, replaced, or obsoleted by other documents at any 40 time. It is inappropriate to use Internet-Drafts as reference 41 material or to cite them other than as "work in progress." 43 This Internet-Draft will expire on September 25, 2018. 45 Copyright Notice 47 Copyright (c) 2018 IETF Trust and the persons identified as the 48 document authors. All rights reserved. 50 This document is subject to BCP 78 and the IETF Trust's Legal 51 Provisions Relating to IETF Documents 52 (https://trustee.ietf.org/license-info) in effect on the date of 53 publication of this document. Please review these documents 54 carefully, as they describe your rights and restrictions with respect 55 to this document. Code Components extracted from this document must 56 include Simplified BSD License text as described in Section 4.e of 57 the Trust Legal Provisions and are provided without warranty as 58 described in the Simplified BSD License. 60 Table of Contents 62 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 63 1.1. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . 3 64 2. OSPF NSPF ID TLV . . . . . . . . . . . . . . . . . . . . . . 4 65 2.1. Flags . . . . . . . . . . . . . . . . . . . . . . . . . . 5 66 2.2. NSPF-ID Fields . . . . . . . . . . . . . . . . . . . . . 5 67 2.3. NSP sub-TLVs . . . . . . . . . . . . . . . . . . . . . . 6 68 2.4. Non-NSP sub-TLVs . . . . . . . . . . . . . . . . . . . . 7 69 3. OSPFv3 NSPF ID TLV . . . . . . . . . . . . . . . . . . . . . 7 70 3.1. OSPFv3 NSPF-ID Fields . . . . . . . . . . . . . . . . . . 9 71 3.2. OSPFv3 NSP sub-TLVs . . . . . . . . . . . . . . . . . . . 10 72 3.3. OSPFv3 Non-NSP sub-TLVs . . . . . . . . . . . . . . . . . 11 73 4. Other Considerations . . . . . . . . . . . . . . . . . . . . 11 74 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11 75 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 76 7. Security Considerations . . . . . . . . . . . . . . . . . . . 12 77 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 78 8.1. Normative References . . . . . . . . . . . . . . . . . . 12 79 8.2. Informative References . . . . . . . . . . . . . . . . . 12 80 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 82 1. Introduction 84 In a network implementing source routing, packets may be transported 85 through the use of segment identifiers (SIDs), where a SID uniquely 86 identifies a segment as defined in [I-D.ietf-spring-segment-routing]. 87 In SR-MPLS, a segment is encoded as a label and an ordered list of 88 segments is encoded as a stack of labels. In SRv6, a segment is 89 encoded as an IPv6 address, with a new type of IPv6 routing header 90 called SRH. An ordered list of segments is encoded as an ordered 91 list of IPv6 addresses in SRH [I-D.ietf-6man-segment-routing-header]. 93 A segment may include one or more nodes, unidirectional adjecencies 94 between two nodes or service instruction by a particular node in the 95 network. A Non Shortest Path (NSP) could be a Traffic Engineered 96 (TE) path or an explicitly provisioned FRR path or a service chained 97 path. NSP can be described using list of segments in SR. However, 98 this creates a problem of having a relatively large stack imposed on 99 the data packet. A path that is encoded with SIDs can be a loose or 100 strict path. In a strict path all the nodes/links on the path are 101 encoded as SIDs, with the expense of number of total SIDs in the 102 stack. 104 The issues caused by the large SID depth, and existing methods for 105 mitigation are introduced in [I-D.ct-isis-nspfid-for-sr-paths] 106 section 1.1 and 1.2. To mitigate the these issues, and also to 107 facilitate forwarding plane a mechanism to identify the SR path with 108 a corresponding data plane identifier for accounting of traffic for 109 SR paths, this draft proposes a new OSPFv2 TLV (Section 2), OSPFv3 110 TLV (Section 3) to advertise the NSPs with Non Shortest Path 111 Forwarding IDentifier (NSPF ID). 113 With corresponding data plane, Section 3 mechanism as in 114 [I-D.ct-isis-nspfid-for-sr-paths], reduces the SID stack in the data 115 plane with a single NSPF ID. 117 1.1. Acronyms 119 EL - Entropy Label 121 ELI - Entropy Label Indicator 123 MPLS - Multi Protocol Label Switching 125 MSD - Maximum SID Depth 127 MTU - Maximum Transferrable Unit 129 NSP - Non Shortest Path 131 SID - Segment Identifier 133 SPF - Shortest Path First 135 SR - Segment Routing 137 SRH - Segment Routing Header 139 SR-MPLS - Segment Routing with MPLS data plane 140 SRv6 - Segment Routing with Ipv6 data plane with SRH 142 SRH - IPv6 Segment Routing Header 144 TE - Traffic Engineering 146 2. OSPF NSPF ID TLV 148 Extended Prefix Opaque LSAs defined in [RFC7684] are used for 149 advertisements of NSPF ID TLV. Multiple OSPF NSPF ID TLVs MAY be 150 advertised in each OSPF Extended Prefix Opaque LSA, but all TLVs 151 included in a single OSPF Extended Prefix Opaque LSA MUST have the 152 same flooding scope. 154 The NSPF-ID TLV has Type TBD (suggested value xxx), and has the 155 following format: 157 0 1 2 3 158 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 1 159 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 160 | Type | Length | 161 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 162 | Flags | AF | Prefix Len | Reserved | 163 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 164 // FEC Prefix (variable) // 165 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 166 | NSPF-ID Type | NSPF-ID Len | NSPF-ID Flags | NSPF-ID Algo | 167 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 168 // NSPF-ID (continued, variable) // 169 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 170 |No.of NSP-STs | NSP sub-TLVs (Variable) // 171 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 172 |No.of Other-STs| Non-NSP sub-TLVs(variable) // 173 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 175 Figure 1: NSPF ID TLV Format 177 Type - TBD (IANA) from OSPF Extended Prefix Opaque LSA registry. 179 Length - Total length of the value field in bytes (variable). 181 Reserved - 1 Octet reserved bits for future use. Reserved bits 182 MUST be reset on transmission and ignored on receive. 184 Flags - Flags for this TLV are described in Section 2.1. 186 AF - Address family for the prefix. Currently, the only supported 187 value is 0 for IPv4 unicast. The inclusion of address family in 188 this TLV allows for future extension. 190 Prefix Len - contains the length of the prefix in bits. 192 FEC Prefix - represents the Forwarding Equivalence Class at the 193 tail-end of the advertised NSP. The "FEC Prefix" corresponds to a 194 routable prefix of the originating node. Value of this field MUST 195 be 4 octets for IPv4 "FEC Prefix". 197 2.1. Flags 199 Flags: 1 octet field of NSPD ID TLV has following flags defined: 201 NSPF ID Flags Format 202 0 1 2 3 4 5 6 7 203 +--+--+--+--+--+--+--+--+ 204 |IA| Rsrvd | 205 +--+--+--+--+--+--+--+--+ 207 w=Where: 209 IA-Flag: Inter-Area flag. If set, advertisement is of inter-area 210 type. An ABR that is advertising the OSPF NSPF ID TLV between 211 areas MUST set this bit. 213 Rsrvd - reserved bits for future use. Reserved bits MUST be reset 214 on transmission and ignored on receive. 216 2.2. NSPF-ID Fields 218 This represents the actual data plane identifier in the packet and 219 could be of any data plane as defined in type field. Both "FEC 220 Prefix" and NSPF-ID MUST belong to a same node in the network. 222 1. NSPF-ID Type: This is a new registry (TBD IANA) for this TLV and 223 the defined types are as follows.Type: 1 - MPLS SID/Label Type: 2 224 Native IPv4 Address 226 2. NSPF-ID Len: Length of the NSPF Identifier field in octets and 227 this depends on the NSPF-ID type. See NSPF-ID below for the 228 length of this field and other considerations. 230 3. NSPF-ID Flags: 1 Octet field for NSPF-ID flags. Some of the bits 231 could be NSPF-ID type specific and each new type MUST define the 232 flags applicable to the NSPF-ID type. For NSPF-ID Type 1, the 233 flags are same as definition in 235 [I-D.ietf-ospf-segment-routing-extensions]. Undefined flags for 236 each NSPF-ID type MUST be considered as reserved. Reserved flag 237 bits in each NSPF-ID type specific flags MUST be reset on 238 transmission and ignored on receive. 240 4. NSPF-ID Algo: 1 octet value represents the SPF algorithm. 241 Algorithm registry is as defined in 242 [I-D.ietf-ospf-segment-routing-extensions]. 244 5. NSPF-ID: This is the NSP forwarding identifier that would be on 245 the data packet. The value of this field is variable and it 246 depends on the NSPF-ID Type. For Type 1, this is and MPLS SID/ 247 Label. For Type 2 this is a 4-byte IPv4 address. For NSPF-ID 248 Type 2, if the NSPF-ID Len is set to 0, then FEC Prefix would 249 also become the NSPF-ID. In the case when NSPF-ID Len is 0, 250 NSPF-ID Type is 2, then FEC Prefix length MUST be a 4-byte IPv4 251 address. 253 6. No.of NSP-STs: Total number of the NSP sub-TLVs are defined with 254 this 1-octet field. The value MUST NOT be zero. 256 2.3. NSP sub-TLVs 258 A new sub-TLV registry is created (TBD IANA) called NSP sub-TLVs. 259 These are used to describe the path in the form of set of contiguous 260 and ordered sub-TLVs, with first sub-TLV representing the top of the 261 stack or first segment. These set of ordered TLVs can have both 262 topological SIDs and non-topological SIDs (e.g., service segments). 264 Type 1: SID/Label sub-TLV as defined in 265 [I-D.ietf-ospf-segment-routing-extensions]. Only Type is defined 266 and Length/Value fields are per secton 2.1 of the referenced 267 document. 269 Type 2: Prefix SID sub-TLV as defined in 270 [I-D.ietf-ospf-segment-routing-extensions]. Only Type is defined 271 and Length/Value fields are per section 5 of the referenced 272 document. 274 Type 3: Adjacency SID sub-TLV as defined in 275 [I-D.ietf-ospf-segment-routing-extensions]. Only Type is defined 276 and Length/Value fields are per section 6 of the referenced 277 document. 279 Type 4: Length 4 bytes, value is 4 bytes IPv4 address encoded 280 similar to IPv4 FEC Prefix described above. 282 2.4. Non-NSP sub-TLVs 284 NSPF ID TLV also defines a new sub-TLV registry (TBD IANA) for 285 defining extensible set of sub-TLVs other than describing the path 286 sub-TLVs. Total number of the path sub-TLVs to describe the path are 287 defined in 1-octet field "No.of Other-STs" just before the Non-NSP 288 sub-TLVs. This field serves as a demarcation for set of ordered NSP 289 sub-TLVs and Non-NSP sub-TLVs. 291 Type 1: Length 0 No value field. Specifies a counter to count 292 number of packets forwarded on this NSPF-ID. 294 Type 2: Length 0 No value field. Specifies a counter to count 295 number of bytes forwarded on this NSPF-ID specified in the network 296 header (e.g. IPv4, IPv6). 298 Type 3: Length 4 bytes, and Value is metric of this path 299 represented through the NSPF-ID. Different nodes can advertise 300 the same NSPF-ID for the same FEC-Prefix with a different set of 301 NSP sub-TLVs and the receiving node MUST consider the lowest 302 metric value (TBD more, what happens when metric is same for two 303 different set of NSP sub-TLVs). 305 3. OSPFv3 NSPF ID TLV 307 The OSPFv3 NSPF ID TLV s a top level TLV of the following LSAs 308 defined in [I-D.ietf-ospf-ospfv3-lsa-extend]. 310 E-Intra-Area-Prefix-LSA 312 E-Inter-Area-Prefix-LSA 314 E-AS-External-LSA 316 E-Type-7-LSA 318 Multiple OSPFv3 NSPF ID TLVs MAY be advertised in each LSA mentioned 319 above. The OSPFv3 NSPF ID TLV has the following format: 321 0 1 2 3 322 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 1 323 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 324 | Type | Length | 325 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 326 | Flags | AF | Prefix Len | Reserved | 327 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 328 // FEC Prefix (variable) // 329 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 330 | NSPF-ID Type | NSPF-ID Len | NSPF-ID Flags | NSPF-ID Algo | 331 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 332 // NSPF-ID (continued, variable) // 333 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 334 |No.of NSP-STs | NSP sub-TLVs (Variable) // 335 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 336 |No.of Other-STs| Non-NSP sub-TLVs(variable) // 337 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 339 Figure 2: OSPFv3 NSPF ID TLV Format 341 where: 343 Type: TBD 345 Length: Variable, in octets, depends on Sub-TLVs. 347 prefix length: Length of prefix in bytes. 349 AF: Address family for the prefix. 351 AF: 0 - IPv4 unicast 353 AF: 1 - IPv6 unicast 355 Flags: Single octet field. The following flags are defined: 357 NSPF ID Flags Format 359 0 1 2 3 4 5 6 7 360 +--+--+--+--+--+--+--+--+ 361 |IA| Rsrvd | 362 +--+--+--+--+--+--+--+--+ 363 IA-Flag: Inter-Area flag. If set, advertisement is of inter- 364 area type. An ABR that is advertising the OSPF NSPF ID TLV 365 between areas MUST set this bit. 366 [I-D.ietf-ospf-ospfv3-segment-routing-extensions] 368 Rsrvd - reserved bits for future use. Reserved bits MUST be 369 reset on transmission and ignored on receive. 371 FEC Prefix - represents the Forwarding Equivalence Class at the 372 tail-end of the advertised NSP. The "FEC Prefix" corresponds to a 373 routable prefix of the originating node. Value of this field MUST 374 be 4 octets for IPv4 "FEC Prefix". Value of this field MUST be 16 375 octets for IPv6 "FEC Prefix". 377 3.1. OSPFv3 NSPF-ID Fields 379 This represents the actual data plane identifier in the packet and 380 could be of any data plane as defined in type field. Both "FEC 381 Prefix" and NSPF-ID MUST belong to a same node in the network. 383 1. NSPF-ID Type: This is a new registry (TBD IANA) for this TLV and 384 the defined types are as follows. Type: 1 - MPLS SID/Label Type: 385 2 Native IPv4 Address Type: 3 Native IPv6 Address Type 4: IPv6 386 SID in SRv6 with SRH 388 2. NSPF-ID Len: Length of the NSPF Identifier field in octets and 389 this depends on the NSPF-ID type. See NSPF-ID below for the 390 length of this field and other considerations. 392 3. NSPF-ID Flags: 1 Octet field for NSPF-ID flags. Some of the bits 393 could be NSPF-ID type specific and each new type MUST define the 394 flags applicable to the NSPF-ID type. For NSPF-ID Type 1, the 395 flags are same as Section 2.1 definition in 396 [I-D.ietf-ospf-segment-routing-extensions]. For NSPF-ID Type 2, 397 3 and NSPF-ID Type 4 only 'R' flag is applicable. Undefined 398 flags for each NSPF-ID type MUST be considered as reserved. 399 Reserved flag bits in each NSPF-ID type specific flags MUST be 400 reset on transmission and ignored on receive. 402 4. NSPF-ID Algo: 1 octet value represents the SPF algorithm. 403 Algorithm registry is as defined in 404 [I-D.ietf-ospf-segment-routing-extensions]. 406 5. NSPF-ID: This is the NSP forwarding identifier that would be on 407 the data packet. The value of this field is variable and it 408 depends on the NSPF-ID Type. For Type 1, this is and MPLS SID/ 409 Label. For Type 2 this is a 4 byte IPv4 address. For Type 3 and 410 Type 4, it is a 16 byte IPv6 address. For NSPF-ID Type 2, 3 or 411 4, if the NSPF-ID Len is set to 0, then FEC Prefix would also 412 become the NSPF-ID. In the case when NSPF-ID Len is 0, NSPF-ID 413 Type is 2, then FEC Prefix length MUST be a 4 byte IPv4 address. 414 Similarly, if NSPF-ID Type is 3 or 4 with NSPF-ID Len is set to 415 0, then FEC Prefix MUST be of a 16 byte IPv6 Address. 417 6. No.of NSP-STs: Total number of the NSP sub-TLVs are defined with 418 this 1-octet field. The value MUST NOT be zero. 420 3.2. OSPFv3 NSP sub-TLVs 422 A new sub-TLV registry is created (TBD IANA) called NSP sub-TLVs. 423 These are used to describe the path in the form of set of contiguous 424 and ordered sub-TLVs, with first sub-TLV representing the top of the 425 stack or first segment. These set of ordered TLVs can have both 426 topological SIDs and non-topological SIDs (e.g., service segments). 428 Type 1: SID/Label sub-TLV as defined in 429 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]. Only Type is 430 defined and Length/Value fields are per section 2.1 of the 431 referenced document. 433 Type 2: Prefix SID sub-TLV as defined in 434 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]. Only Type is 435 defined and Length/Value fields are per section 5 of the 436 referenced document. 438 Type 3: Adjacency SID sub-TLV as defined in 439 [I-D.ietf-ospf-ospfv3-segment-routing-extensions]. Only Type is 440 defined and Length/Value fields are per section 6 of the 441 referenced document. 443 Type 4: Length 4 bytes, value is 4 bytes IPv4 address encoded 444 similar to IPv4 FEC Prefix described above. 446 Type 5: Length 16 bytes; value is 16 bytes IPv6 address encoded 447 similar to IPv6 FEC Prefix described above. 449 Type 6: SRv6 Node SID TLV as defined in 450 [I-D.li-ospf-ospfv3-srv6-extensions]. Only Type is defined and 451 Length/Value fields are in the referenced document. 453 Type 7: SRv6 Adjacency-SID sub-TLV as defined in 454 [I-D.li-ospf-ospfv3-srv6-extensions]. Only Type is defined and 455 Length/Value fields are in the referenced document. 457 Type 8: SRv6 LAN Adjacency-SID sub-TLV as defined in 458 [I-D.li-ospf-ospfv3-srv6-extensions]. Only Type is defined and 459 Length/Value fields are in the referenced document. 461 3.3. OSPFv3 Non-NSP sub-TLVs 463 NSPF ID TLV also defines a new sub-TLV registry (TBD IANA) for 464 defining extensible set of sub-TLVs other than describing the path 465 sub-TLVs. Total number of the path sub-TLVs to describe the path are 466 defined in 1-octet field "No.of Other-STs" just before the Non-NSP 467 sub-TLVs. This field serves as a demarcation for set of ordered NSP 468 sub-TLVs and Non-NSP sub-TLVs. 470 Type 1: Length 0 No value field. Specifies a counter to count 471 number of packets forwarded on this NSPF-ID. 473 Type 2: Length 0 No value field. Specifies a counter to count 474 number of bytes forwarded on this NSPF-ID specified in the network 475 header (e.g. IPv4, IPv6). 477 Type 3: Length 4 bytes, and Value is metric of this path 478 represented through the NSPF-ID. Different nodes can advertise 479 the same NSPF-ID for the same FEC-Prefix with a different set of 480 NSP sub-TLVs and the receiving node MUST consider the lowest 481 metric value (TBD more, what happens when metric is same for two 482 different set of NSP sub-TLVs). 484 4. Other Considerations 486 Please refer to [I-D.ct-isis-nspfid-for-sr-paths] section 3, 4 and 5. 488 5. Acknowledgements 490 Thanks to Richard Li, Alex Clemm, Kiran Makhijani and Lin Han for 491 initial discussions on this topic. 493 Earlier versions of draft-ietf-ospf-segment-routing-extensions have a 494 mechanism to advertise EROs through Binding SID. 496 6. IANA Considerations 498 This document requests the following new TLV in IANA OSPFv2 and 499 OSPFv3 TLV code-point registry. 501 TLV # Name 502 ----- -------------- 503 TBD NSPF ID TLV 505 This document also requests IANA to create new registries for NSPF ID 506 TLV Flags field, NSPF-ID Type, NSPF-ID Flags, NSP sub-TLVs and Non- 507 NSP sub-TLVs in NSPF ID TLV as described in Section 2 and Section 3. 509 7. Security Considerations 511 Existing security extensions as described in [RFC2328] and [RFC7684] 512 apply to these segment routing extensions. While OSPF is under a 513 single administrative domain, there can be deployments where 514 potential attackers have access to one or more networks in the OSPF 515 routing domain. In these deployments, stronger authentication 516 mechanisms such as those specified in [RFC7474] SHOULD be used. 518 Advertisement of the additional information defined in this document 519 introduces no new security concerns in OSPF protocol. However as 520 this extension is related to SR-MPLS and SRH data planes as defined 521 in [I-D.ietf-spring-segment-routing], those particular data plane 522 security considerations does apply here. 524 8. References 526 8.1. Normative References 528 [I-D.ct-isis-nspfid-for-sr-paths] 529 Chunduri, U., Tantsura, J., and Y. Qu, "Usage of Non 530 Shortest Path Forwarding (NSPF) IDs in IS-IS", draft-ct- 531 isis-nspfid-for-sr-paths-01 (work in progress), March 532 2018. 534 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 535 Requirement Levels", BCP 14, RFC 2119, 536 DOI 10.17487/RFC2119, March 1997, 537 . 539 [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, 540 DOI 10.17487/RFC2328, April 1998, 541 . 543 8.2. Informative References 545 [I-D.hegde-spring-traffic-accounting-for-sr-paths] 546 Hegde, S., "Traffic Accounting for MPLS Segment Routing 547 Paths", draft-hegde-spring-traffic-accounting-for-sr- 548 paths-01 (work in progress), October 2017. 550 [I-D.ietf-6man-segment-routing-header] 551 Previdi, S., Filsfils, C., Leddy, J., Matsushima, S., and 552 d. daniel.voyer@bell.ca, "IPv6 Segment Routing Header 553 (SRH)", draft-ietf-6man-segment-routing-header-10 (work in 554 progress), March 2018. 556 [I-D.ietf-ospf-ospfv3-lsa-extend] 557 Lindem, A., Roy, A., Goethals, D., Vallem, V., and F. 558 Baker, "OSPFv3 LSA Extendibility", draft-ietf-ospf-ospfv3- 559 lsa-extend-23 (work in progress), January 2018. 561 [I-D.ietf-ospf-ospfv3-segment-routing-extensions] 562 Psenak, P., Filsfils, C., Previdi, S., Gredler, H., 563 Shakir, R., Henderickx, W., and J. Tantsura, "OSPFv3 564 Extensions for Segment Routing", draft-ietf-ospf-ospfv3- 565 segment-routing-extensions-11 (work in progress), January 566 2018. 568 [I-D.ietf-ospf-segment-routing-extensions] 569 Psenak, P., Previdi, S., Filsfils, C., Gredler, H., 570 Shakir, R., Henderickx, W., and J. Tantsura, "OSPF 571 Extensions for Segment Routing", draft-ietf-ospf-segment- 572 routing-extensions-24 (work in progress), December 2017. 574 [I-D.ietf-ospf-segment-routing-msd] 575 Tantsura, J., Chunduri, U., Aldrin, S., and P. Psenak, 576 "Signaling MSD (Maximum SID Depth) using OSPF", draft- 577 ietf-ospf-segment-routing-msd-09 (work in progress), 578 February 2018. 580 [I-D.ietf-spring-segment-routing] 581 Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B., 582 Litkowski, S., and R. Shakir, "Segment Routing 583 Architecture", draft-ietf-spring-segment-routing-15 (work 584 in progress), January 2018. 586 [I-D.li-ospf-ospfv3-srv6-extensions] 587 Li, Z., Hu, Z., Cheng, D., Talaulikar, K., and P. Psenak, 588 "OSPFv3 Extensions for SRv6", draft-li-ospf- 589 ospfv3-srv6-extensions-01 (work in progress), March 2018. 591 [RFC4915] Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P. 592 Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF", 593 RFC 4915, DOI 10.17487/RFC4915, June 2007, 594 . 596 [RFC7474] Bhatia, M., Hartman, S., Zhang, D., and A. Lindem, Ed., 597 "Security Extension for OSPFv2 When Using Manual Key 598 Management", RFC 7474, DOI 10.17487/RFC7474, April 2015, 599 . 601 [RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W., 602 Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute 603 Advertisement", RFC 7684, DOI 10.17487/RFC7684, November 604 2015, . 606 Authors' Addresses 608 Uma Chunduri 609 Huawei USA 610 2330 Central Expressway 611 Santa Clara, CA 95050 612 USA 614 Email: uma.chunduri@huawei.com 616 Yingzhen Qu 617 Huawei USA 618 2330 Central Expressway 619 Santa Clara, CA 95050 620 USA 622 Email: yingzhen.qu@huawei.com 624 Jeff Tantsura 625 Nuage Networks 626 755 Ravendale Drive 627 Mountain View, CA 94043 628 USA 630 Email: jefftant.ietf@gmail.com