idnits 2.17.1 draft-ietf-mpls-residence-time-11.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == Line 952 has weird spacing: '...Allowed on ...' -- The document date (July 21, 2016) is 2807 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) -- Possible downref: Non-RFC (?) normative reference: ref. 'IEEE.1588.2008' == Outdated reference: A later version (-23) exists of draft-ietf-ospf-ospfv3-lsa-extend-10 -- Obsolete informational reference (is this intentional?): RFC 5226 (Obsoleted by RFC 8126) Summary: 0 errors (**), 0 flaws (~~), 3 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 MPLS Working Group G. Mirsky 3 Internet-Draft S. Ruffini 4 Intended status: Standards Track E. Gray 5 Expires: January 22, 2017 Ericsson 6 J. Drake 7 Juniper Networks 8 S. Bryant 9 Independent 10 A. Vainshtein 11 ECI Telecom 12 July 21, 2016 14 Residence Time Measurement in MPLS network 15 draft-ietf-mpls-residence-time-11 17 Abstract 19 This document specifies G-ACh based Residence Time Measurement and 20 how it can be used by time synchronization protocols being 21 transported over MPLS domain. 23 Residence time is the variable part of propagation delay of timing 24 and synchronization messages and knowing what this delay is for each 25 message allows for a more accurate determination of the delay to be 26 taken into account in applying the value included in a PTP event 27 message. 29 Status of This Memo 31 This Internet-Draft is submitted in full conformance with the 32 provisions of BCP 78 and BCP 79. 34 Internet-Drafts are working documents of the Internet Engineering 35 Task Force (IETF). Note that other groups may also distribute 36 working documents as Internet-Drafts. The list of current Internet- 37 Drafts is at http://datatracker.ietf.org/drafts/current/. 39 Internet-Drafts are draft documents valid for a maximum of six months 40 and may be updated, replaced, or obsoleted by other documents at any 41 time. It is inappropriate to use Internet-Drafts as reference 42 material or to cite them other than as "work in progress." 44 This Internet-Draft will expire on January 22, 2017. 46 Copyright Notice 48 Copyright (c) 2016 IETF Trust and the persons identified as the 49 document authors. All rights reserved. 51 This document is subject to BCP 78 and the IETF Trust's Legal 52 Provisions Relating to IETF Documents 53 (http://trustee.ietf.org/license-info) in effect on the date of 54 publication of this document. Please review these documents 55 carefully, as they describe your rights and restrictions with respect 56 to this document. Code Components extracted from this document must 57 include Simplified BSD License text as described in Section 4.e of 58 the Trust Legal Provisions and are provided without warranty as 59 described in the Simplified BSD License. 61 Table of Contents 63 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 64 1.1. Conventions used in this document . . . . . . . . . . . . 3 65 1.1.1. Terminology . . . . . . . . . . . . . . . . . . . . . 3 66 1.1.2. Requirements Language . . . . . . . . . . . . . . . . 4 67 2. Residence Time Measurement . . . . . . . . . . . . . . . . . 4 68 3. G-ACh for Residence Time Measurement . . . . . . . . . . . . 5 69 3.1. PTP Packet Sub-TLV . . . . . . . . . . . . . . . . . . . 6 70 4. Control Plane Theory of Operation . . . . . . . . . . . . . . 7 71 4.1. RTM Capability . . . . . . . . . . . . . . . . . . . . . 7 72 4.2. RTM Capability Sub-TLV . . . . . . . . . . . . . . . . . 8 73 4.3. RTM Capability Advertisement in OSPFv2 . . . . . . . . . 9 74 4.4. RTM Capability Advertisement in OSPFv3 . . . . . . . . . 9 75 4.5. RTM Capability Advertisement in IS-IS . . . . . . . . . . 9 76 4.6. RSVP-TE Control Plane Operation to Support RTM . . . . . 10 77 4.7. RTM_SET TLV . . . . . . . . . . . . . . . . . . . . . . . 11 78 4.7.1. RTM_SET Sub-TLVs . . . . . . . . . . . . . . . . . . 13 79 5. Data Plane Theory of Operation . . . . . . . . . . . . . . . 16 80 6. Applicable PTP Scenarios . . . . . . . . . . . . . . . . . . 16 81 7. One-step Clock and Two-step Clock Modes . . . . . . . . . . . 17 82 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 83 8.1. New RTM G-ACh . . . . . . . . . . . . . . . . . . . . . . 19 84 8.2. New RTM TLV Registry . . . . . . . . . . . . . . . . . . 19 85 8.3. New RTM Sub-TLV Registry . . . . . . . . . . . . . . . . 20 86 8.4. RTM Capability sub-TLV in OSPFv2 . . . . . . . . . . . . 20 87 8.5. IS-IS RTM Application ID . . . . . . . . . . . . . . . . 21 88 8.6. RTM_SET Sub-object RSVP Type and sub-TLVs . . . . . . . . 21 89 8.7. RTM_SET Attribute Flag . . . . . . . . . . . . . . . . . 22 90 8.8. New Error Codes . . . . . . . . . . . . . . . . . . . . . 22 91 9. Security Considerations . . . . . . . . . . . . . . . . . . . 23 92 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 23 93 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 23 94 11.1. Normative References . . . . . . . . . . . . . . . . . . 23 95 11.2. Informative References . . . . . . . . . . . . . . . . . 25 96 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25 98 1. Introduction 100 Time synchronization protocols, e.g., Network Time Protocol version 4 101 (NTPv4) [RFC5905] and Precision Time Protocol (PTP) Version 2 102 [IEEE.1588.2008] define timing messages that can be used to 103 synchronize clocks across a network domain. Measurement of the 104 cumulative time one of these timing messages spends transiting the 105 nodes on the path from ingress node to egress node is termed 106 Residence Time and it is used to improve the accuracy of clock 107 synchronization. (I.e., it is the sum of the difference between the 108 time of receipt at an ingress interface and the time of transmission 109 from an egress interface for each node along the path from ingress 110 node to egress node.) This document defines a new Generalized 111 Associated Channel (G-ACh) value and an associated residence time 112 measurement (RTM) packet that can be used in a Multi-Protocol Label 113 Switching (MPLS) network to measure residence time over a Label 114 Switched Path (LSP). 116 Although it is possible to use RTM over an LSP instantiated using 117 LDP, that is outside the scope of this document. Rather, this 118 document describes RTM over an LSP signaled using RSVP-TE [RFC3209] 119 because the LSP's path can be either explicitly specified or 120 determined during signaling. 122 Comparison with alternative proposed solutions such as 123 [I-D.ietf-tictoc-1588overmpls] is outside the scope of this document. 125 1.1. Conventions used in this document 127 1.1.1. Terminology 129 MPLS: Multi-Protocol Label Switching 131 ACH: Associated Channel 133 TTL: Time-to-Live 135 G-ACh: Generic Associated Channel 137 GAL: Generic Associated Channel Label 139 NTP: Network Time Protocol 141 ppm: parts per million 142 PTP: Precision Time Protocol 144 LSP: Label Switched Path 146 OAM: Operations, Administration, and Maintenance 148 RRO: Record Route Object 150 RTM: Residence Time Measurement 152 IGP: Internal Gateway Protocol 154 1.1.2. Requirements Language 156 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 157 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 158 "OPTIONAL" in this document are to be interpreted as described in 159 [RFC2119]. 161 2. Residence Time Measurement 163 Packet Loss and Delay Measurement for MPLS Networks [RFC6374] can be 164 used to measure one-way or two-way end-to-end propagation delay over 165 LSP or PW. But these measurements are insufficient for use in some 166 applications, for example, time synchronization across a network as 167 defined in the Precision Time Protocol (PTP). In PTPv2 168 [IEEE.1588.2008] residence times is accumulated in the 169 correctionField of the PTP event message, as defined in 170 [IEEE.1588.2008], or in the associated follow-up message (or 171 Delay_Resp message associated with the Delay_Req message) in case of 172 two-step clocks (see the detailed discussion in Section 7). 174 IEEE 1588 uses this residence time to correct the transit time from 175 ingress node to egress node, effectively making the transit nodes 176 transparent. 178 This document proposes a mechanism that can be used as one of types 179 of on-path support for a clock synchronization protocol or to perform 180 one-way measurement of residence time. The proposed mechanism 181 accumulates residence time from all nodes that support this extension 182 along the path of a particular LSP in Scratch Pad field of an RTM 183 packet Figure 1. This value can then be used by the egress node to 184 update, for example, the correctionField of the PTP event packet 185 carried within the RTM packet prior to performing its PTP processing. 187 3. G-ACh for Residence Time Measurement 189 RFC 5586 [RFC5586] and RFC 6423 [RFC6423] define the G-ACh to extend 190 the applicability of the PW Associated Channel (ACH) [RFC5085] to 191 LSPs. G-ACh provides a mechanism to transport OAM and other control 192 messages over an LSP. Processing of these messages by select transit 193 nodes is controlled by the use of the Time-to-Live (TTL) value in the 194 MPLS header of these messages. 196 The packet format for Residence Time Measurement (RTM) is presented 197 in Figure 1 199 0 1 2 3 200 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 1 201 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 202 |0 0 0 1|Version| Reserved | RTM G-ACh | 203 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 204 | | 205 | Scratch Pad | 206 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 207 | Type | Length | 208 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 209 | Value | 210 ~ ~ 211 | | 212 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 214 Figure 1: RTM G-ACh packet format for Residence Time Measurement 216 o First four octets are defined as G-ACh Header in [RFC5586] 218 o The Version field is set to 0, as defined in RFC 4385 [RFC4385]. 220 o The Reserved field MUST be set to 0 on transmit and ignored on 221 receipt. 223 o The RTM G-ACh field, value (TBA1) to be allocated by IANA, 224 identifies the packet as such. 226 o The Scratch Pad field is 8 octets in length. It is used to 227 accumulate the residence time spent in each RTM capable node 228 transited by the packet on its path from ingress node to egress 229 node. The first RTM-capable node MUST initialize the Scratch Pad 230 field with its residence time measurement. Its format is IEEE 231 double precision and its units are nanoseconds. Note that 232 depending on whether the timing procedure is one-step or two-step 233 operation (Section 7), the residence time is either for the timing 234 packet carried in the Value field of this RTM packet or for an 235 associated timing packet carried in the Value field of another RTM 236 packet. 238 o The Type field identifies the type and encapsulation of a timing 239 packet carried in the Value field, e.g., NTP [RFC5905] or PTP 240 [IEEE.1588.2008]. IANA will be asked to create a sub-registry in 241 Generic Associated Channel (G-ACh) Parameters Registry called 242 "MPLS RTM TLV Registry". 244 o The Length field contains the length, in octets , of the of the 245 timing packet carried in the Value field. 247 o The optional Value field MAY carry a packet of the time 248 synchronization protocol identified by Type field. It is 249 important to note that the packet may be authenticated or 250 encrypted and carried over LSP edge to edge unchanged while the 251 residence time is accumulated in the Scratch Pad field. 253 o The TLV MUST be included in the RTM message, even if the length of 254 the Value field is zero. 256 3.1. PTP Packet Sub-TLV 258 Figure 2 presents format of a PTP sub-TLV that MUST be included in 259 the Value field of an RTM packet preceding the carried timing packet 260 when the timing packet is PTP. 262 0 1 2 3 263 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 1 264 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 265 | Type | Length | 266 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 267 | Flags |PTPType| 268 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 269 | Port ID | 270 | | 271 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 272 | | Sequence ID | 273 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 275 Figure 2: PTP Sub-TLV format 277 where Flags field has format 278 0 1 2 279 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 7 280 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 281 |S| Reserved | 282 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 284 Figure 3: Flags field format of PTP Packet Sub-TLV 286 o The Type field identifies PTP sub-TLV defined in the Table 19 287 Values of messageType field in [IEEE.1588.2008]. 289 o The Length field of the PTP sub-TLV contains the number of octets 290 of the Value field and MUST be 20. 292 o The Flags field currently defines one bit, the S-bit, that defines 293 whether the current message has been processed by a 2-step node, 294 where the flag is cleared if the message has been handled 295 exclusively by 1-step nodes and there is no follow-up message, and 296 set if there has been at least one 2-step node and a follow-up 297 message is forthcoming. 299 o The PTPType indicates the type of PTP packet carried in the TLV. 300 PTPType is the messageType field of the PTPv2 packet whose values 301 are defined in the Table 19 [IEEE.1588.2008]. 303 o The 10 octets long Port ID field contains the identity of the 304 source port. 306 o The Sequence ID is the sequence ID of the PTP message carried in 307 the Value field of the message. 309 4. Control Plane Theory of Operation 311 The operation of RTM depends upon TTL expiry to deliver an RTM packet 312 from one RTM capable interface to the next along the path from 313 ingress node to egress node. This means that a node with RTM capable 314 interfaces MUST be able to compute a TTL which will cause the expiry 315 of an RTM packet at the next node with RTM capable interfaces. 317 4.1. RTM Capability 319 Note that the RTM capability of a node is with respect to the pair of 320 interfaces that will be used to forward an RTM packet. In general, 321 the ingress interface of this pair must be able to capture the 322 arrival time of the packet and encode it in some way such that this 323 information will be available to the egress interface. 325 The supported modes (1-step verses 2-step) of any pair of interfaces 326 is then determined by the capability of the egress interface. For 327 both modes, the egress interface implementation MUST be able to 328 determine the precise departure time of the same packet and determine 329 from this, and the arrival time information from the corresponding 330 ingress interface, the difference representing the residence time for 331 the packet. 333 An interface with the ability to do this and update the associated 334 Scratch Pad in real-time (i.e. while the packet is being forwarded) 335 is said to be 1-step capable. 337 Hence while both ingress and egress interfaces are required to 338 support RTM for the pair to be RTM-capable, it is the egress 339 interface that determines whether or not the node is 1-step or 2-step 340 capable with respect to the interface-pair. 342 The RTM capability used in the sub-TLV shown in Figure 4 is thus 343 associated with the egress port of the node making the advertisement, 344 while the ability of any pair of interfaces that includes this egress 345 interface to support any mode of RTM depends on the ability of that 346 interface to record packet arrival time in some way that can be 347 conveyed to and used by that egress interface. 349 When a node uses an IGP to carry the RTM capability sub-TLV, the sub- 350 TLV MUST reflect the RTM capability (1-step or 2-step) associated 351 with egress interfaces. 353 4.2. RTM Capability Sub-TLV 355 The format for the RTM Capabilities sub-TLV is presented in Figure 4 357 0 1 2 3 358 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 1 359 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 360 | Type | Length | 361 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 362 | RTM | Reserved | 363 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 365 Figure 4: RTM Capability sub-TLV 367 o Type value (TBA2) will be assigned by IANA from appropriate 368 registry for OSPFv2. 370 o Length MUST be set to 4. 372 o RTM (capability) - is a three-bit long bit-map field with values 373 defined as follows: 375 * 0b001 - one-step RTM supported; 377 * 0b010 - two-step RTM supported; 379 * 0b100 - reserved. 381 o Reserved field must be set to all zeroes on transmit and ignored 382 on receipt. 384 [RFC4202] explains that the Interface Switching Capability Descriptor 385 describes switching capability of an interface. For bi-directional 386 links, the switching capabilities of an interface are defined to be 387 the same in either direction. I.e., for data entering the node 388 through that interface and for data leaving the node through that 389 interface. That principle SHOULD be applied when a node advertises 390 RTM Capability. 392 A node that supports RTM MUST be able to act in two-step mode and MAY 393 also support one-step RTM mode. Detailed discussion of one-step and 394 two-step RTM modes in Section 7. 396 4.3. RTM Capability Advertisement in OSPFv2 398 The capability to support RTM on a particular link (interface) is 399 advertised in the OSPFv2 Extended Link Opaque LSA described in 400 Section 3 [RFC7684] via the RTM Capability sub-TLV. 402 Its Type value will be assigned by IANA from the OSPF Extended Link 403 TLV Sub-TLVs registry that will be created per [RFC7684] request. 405 4.4. RTM Capability Advertisement in OSPFv3 407 The capability to support RTM on a particular link (interface) can be 408 advertised in OSPFv3 using LSA extensions as described in 409 [I-D.ietf-ospf-ospfv3-lsa-extend]. Exact use of OSPFv3 LSA 410 extensions is for further study. 412 4.5. RTM Capability Advertisement in IS-IS 414 The capability to support RTM on a particular link (interface) is 415 advertised in the GENINFO TLV described in [RFC6823] via the RTM 416 Capability sub-TLV. 418 With respect to the Flags field of the GENINFO TLV: 420 o The S bit MUST be cleared to prevent the RTM Capability sub-TLV 421 from leaking between levels. 423 o The D bit of the Flags field MUST be cleared as required by 424 [RFC6823]. 426 o The I bit and the V bit MUST be set accordingly depending on 427 whether RTM capability being advertised is for an IPv4 or an IPv6 428 interface. 430 Application ID (TBA3) will be assigned from the Application 431 Identifiers for TLV 251 IANA registry. The RTM Capability sub-TLV 432 MUST be included in GENINFO TLV in Application Specific Information. 434 4.6. RSVP-TE Control Plane Operation to Support RTM 436 Throughout this document we refer to a node as RTM capable node when 437 at least one of its interfaces is RTM capable. Figure 5 provides an 438 example of roles a node may have with respect to RTM capability: 440 ----- ----- ----- ----- ----- ----- ----- 441 | A |-----| B |-----| C |-----| D |-----| E |-----| F |-----| G | 442 ----- ----- ----- ----- ----- ----- ----- 444 Figure 5: RTM capable roles 446 o A is a Boundary Clock with its egress port in Master state. Node 447 A transmits IP encapsulated timing packets whose destination IP 448 address is G. 450 o B is the ingress LER for the MPLS LSP and is the first RTM capable 451 node. It creates RTM packets and in each it places a timing 452 packet, possibly encrypted, in the Value field and initializes the 453 Scratch Pad field with its residence time measurement 455 o C is a transit node that is not RTM capable. It forwards RTM 456 packets without modification. 458 o D is RTM capable transit node. It updates the Scratch Pad filed 459 of the RTM packet without updating of the timing packet. 461 o E is a transit node that is not RTM capable. It forwards RTM 462 packets without modification. 464 o F is the egress LER and the last RTM capable node. It processes 465 the timing packet carried in the Value field using the value in 466 the Scratch Pad field. It updates the Correction field of the PTP 467 message with the value in the Scratch Pad field of the RTM ACH, 468 and removes the RTM ACH encapsulation. 470 o G is a Boundary Clock with its ingress port in Slave state. Node 471 G receives PTP messages. 473 An ingress node that is configured to perform RTM along a path 474 through an MPLS network to an egress node verifies that the selected 475 egress node has an interface that supports RTM via the egress node's 476 advertisement of the RTM Capability sub-TLV. In the Path message 477 that the ingress node uses to instantiate the LSP to that egress node 478 it places LSP_ATTRIBUTES Object [RFC5420] with RTM_SET Attribute Flag 479 set Section 8.7 which indicates to the egress node that RTM is 480 requested for this LSP. RTM_SET Attribute Flag SHOULD NOT be set in 481 the LSP_REQUIRED_ATTRIBUTES object [RFC5420] , unless it is known 482 that all nodes support RTM, because a node that does not recognize 483 RTM_SET Attribute Flag would reject the Path message. 485 If egress node receives Path message with RTM_SET Attribute Flag in 486 LSP_ATTRIBUTES object, it MUST include initialized RRO [RFC3209] and 487 LSP_ATTRIBUTES object where RTM_SET Attribute Flag is set and RTM_SET 488 TLV Section 4.7 is initialized. When Resv message received by 489 ingress node the RTM_SET TLV will contain an ordered list, from 490 egress node to ingress node, of the RTM capable node along the LSP's 491 path. 493 After the ingress node receives the Resv, it MAY begin sending RTM 494 packets on the LSP's path. Each RTM packet has its Scratch Pad field 495 initialized and its TTL set to expire on the closest downstream RTM 496 capable node. 498 It should be noted that RTM can also be used for LSPs instantiated 499 using [RFC3209] in an environment in which all interfaces in an IGP 500 support RTM. In this case the RTM_SET TLV and LSP_ATTRIBUTES Object 501 MAY be omitted. 503 4.7. RTM_SET TLV 505 RTM capable interfaces can be recorded via RTM_SET TLV. The RTM_SET 506 sub-object format is of generic Type, Length, Value (TLV), presented 507 in Figure 6 . 509 0 1 2 3 510 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 1 511 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 512 | Type | Length |I| Reserved | 513 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 514 ~ Value ~ 515 | | 516 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 518 Figure 6: RTM_SET TLV format 520 Type value (TBA4) will be assigned by IANA from its Attributes TLV 521 Space sub-registry. 523 The Length contains the total length of the sub-object in bytes, 524 including the Type and Length fields. 526 The I bit flag indicates whether the downstream RTM capable node 527 along the LSP is present in the RRO. 529 Reserved field must be zeroed on initiation and ignored on receipt. 531 The content of an RTM_SET TLV is a series of variable-length sub- 532 TLVs. Only a single RTM_SET can be present in the LSP_ATTRIBUTES 533 object. The sub-TLVs are defined in Section 4.7.1 below. 535 The following processing procedures apply to every RTM capable node 536 along the LSP that in this paragraph is referred as node for sake of 537 brevity. Each node MUST examine Resv message whether RTM_SET 538 Attribute Flag in the LSP_ATTRIBUTES object is set. If the RTM_SET 539 flag set, the node MUST inspect the LSP_ATTRIBUTES object for 540 presence of RTM_SET TLV. If more than one found, then the LSP setup 541 MUST fail with generation of the ResvErr message with Error Code 542 Duplicate TLV Section 8.8 and Error Value that contains Type value in 543 its 8 least significant bits. If no RTM_SET TLV has been found, then 544 the LSP setup MUST fail with generation of the ResvErr message with 545 Error Code RTM_SET TLV Absent Section 8.8. If one RTM_SET TLV has 546 been found the node will use the ID of the first node in the RTM_SET 547 in conjunction with the RRO to compute the hop count to its 548 downstream node with reachable RTM capable interface. If the node 549 cannot find matching ID in RRO, then it MUST try to use ID of the 550 next node in the RTM_SET until it finds the match or reaches the end 551 of RTM_SET TLV. If match have been found, then the calculated value 552 is used by the node as TTL value in outgoing label to reach the next 553 RTM capable node on the LSP. Otherwise, the TTL value MUST be set to 554 255. The node MUST add RTM_SET sub-TLV with the same address it used 555 in RRO sub-object at the beginning of the RTM_SET TLV in associated 556 outgoing Resv message before forwarding it upstream. If the 557 calculated TTL value been set to 255, as described above, then the I 558 flag in node RTM_SET TLV MUST be set to 1 before Resv message 559 forwarded upstream. Otherwise, the I flag MUST be cleared (0). 561 The ingress node MAY inspect the I bit flag received in each RTM_SET 562 TLV contained in the LSP_ATTRIBUTES object of a received Resv 563 message. Presence of the RTM_SET TLV with I bit field set to 1 564 indicates that some RTM nodes along the LSP could be included in the 565 calculation of the residence time. An ingress node MAY choose to 566 resignal the LSP to include all RTM nodes or simply notify the user 567 via a management interface. 569 There are scenarios when some information is removed from an RRO due 570 to policy processing (e.g., as may happen between providers) or RRO 571 is limited due to size constraints . Such changes affect the core 572 assumption of the method to control processing of RTM packets. RTM 573 SHOULD NOT be used if it is not guaranteed that RRO contains complete 574 information. 576 4.7.1. RTM_SET Sub-TLVs 578 The RTM Set sub-object contains an ordered list, from egress node to 579 ingress node, of the RTM capable nodes along the LSP's path. 581 The contents of a RTM_SET sub-object are a series of variable-length 582 sub-TLVs. Each sub-TLV has its own Length field. The Length 583 contains the total length of the sub-TLV in bytes, including the Type 584 and Length fields. The Length MUST always be a multiple of 4, and at 585 least 8 (smallest IPv4 sub-object). 587 Sub-TLVs are organized as a last-in-first-out stack. The first -out 588 sub-TLV relative to the beginning of RTM_SET TLV is considered the 589 top. The last-out sub-TLV is considered the bottom. When a new sub- 590 TLV is added, it is always added to the top. Only a single RTM_SET 591 sub-TLV with the given Value field MUST be present in the RTM_SET 592 TLV. If more than one sub-TLV is found the LSP setup MUST fail with 593 the generation of a ResvErr message with the Error Code "Duplicate 594 sub-TLV" Section 8.8 and Error Value contains 16-bit value composed 595 of (Type of TLV, Type of sub-TLV). 597 Three kinds of sub-TLVs for RTM_SET are currently defined. 599 4.7.1.1. IPv4 Sub-TLV 600 0 1 2 3 601 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 1 602 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 603 | Type | Length | Reserved | 604 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 605 | IPv4 address | 606 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 608 Figure 7: IPv4 sub-TLV format 610 Type 612 0x01 IPv4 address 614 Length 616 The Length contains the total length of the sub-TLV in bytes, 617 including the Type and Length fields. The Length is always 8. 619 IPv4 address 621 A 32-bit unicast host address. 623 Reserved 625 Zeroed on initiation and ignored on receipt. 627 4.7.1.2. IPv6 Sub-TLV 629 0 1 2 3 630 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 1 631 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 632 | Type | Length | Reserved | 633 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 634 | | 635 | IPv6 address | 636 | | 637 | | 638 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 640 Figure 8: IPv6 sub-TLV format 642 Type 644 0x02 IPv6 address 646 Length 647 The Length contains the total length of the sub-TLV in bytes, 648 including the Type and Length fields. The Length is always 20. 650 IPv6 address 652 A 128-bit unicast host address. 654 Reserved 656 Zeroed on initiation and ignored on receipt. 658 4.7.1.3. Unnumbered Interface Sub-TLV 660 0 1 2 3 661 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 1 662 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 663 | Type | Length | Reserved | 664 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 665 | Node ID | 666 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 667 | Interface ID | 668 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 670 Figure 9: IPv4 sub-TLV format 672 Type 674 0x03 Unnumbered interface 676 Length 678 The Length contains the total length of the sub-TLV in bytes, 679 including the Type and Length fields. The Length is always 12. 681 Node ID 683 The Node ID interpreted as Router ID as discussed in the Section 2 684 [RFC3477]. 686 Interface ID 688 The identifier assigned to the link by the node specified by the 689 Node ID. 691 Reserved 693 Zeroed on initiation and ignored on receipt. 695 5. Data Plane Theory of Operation 697 After instantiating an LSP for a path using RSVP-TE [RFC3209] as 698 described in Section 4.6 or as described in the second paragraph of 699 Section 4 and in Section 4.6, ingress node MAY begin sending RTM 700 packets to the first downstream RTM capable node on that path. Each 701 RTM packet has its Scratch Pad field initialized and its TTL set to 702 expire on the next downstream RTM-capable node. Each RTM-capable 703 node on the explicit path receives an RTM packet and records the time 704 at which it receives that packet at its ingress interface as well as 705 the time at which it transmits that packet from its egress interface; 706 this should be done as close to the physical layer as possible to 707 ensure precise accuracy in time determination. The RTM-capable node 708 determines the difference between those two times; for 1-step 709 operation, this difference is determined just prior to or while 710 sending the packet, and the RTM-capable egress interface adds it to 711 the value in the Scratch Pad field of the message in progress. Note, 712 for the purpose of calculating a residence time, a common free 713 running clock synchronizing all the involved interfaces may be 714 sufficient, as, for example, 4.6 ppm accuracy leads to 4.6 nanosecond 715 error for residence time on the order of 1 millisecond. 717 For 2-step operation, the difference between packet arrival time (at 718 an ingress interface) and subsequent departure time (from an egress 719 interface) is determined at some later time prior to sending a 720 subsequent follow-up message, so that this value can be used to 721 update the correctionField in the follow-up message. 723 See Section 7 for further details on the difference between 1-step 724 and 2-step operation. 726 The last RTM-capable node on the LSP MAY then use the value in the 727 Scratch Pad field to perform time correction, if there is no follow- 728 up message. For example, the egress node may be a PTP Boundary Clock 729 synchronized to a Master Clock and will use the value in the Scratch 730 Pad field to update PTP's correctionField. 732 6. Applicable PTP Scenarios 734 The proposed approach can be directly integrated in a PTP network 735 based on the IEEE 1588 delay request-response mechanism. The RTM 736 capable node nodes act as end-to-end transparent clocks, and 737 typically boundary clocks, at the edges of the MPLS network, use the 738 value in the Scratch Pad field to update the correctionField of the 739 corresponding PTP event packet prior to performing the usual PTP 740 processing. 742 7. One-step Clock and Two-step Clock Modes 744 One-step mode refers to the mode of operation where an egress 745 interface updates the correctionField value of an original event 746 message. Two-step mode refers to the mode of operation where this 747 update is made in a subsequent follow-up message. 749 Processing of the follow-up message, if present, requires the 750 downstream end-point to wait for the arrival of the follow-up message 751 in order to combine correctionField values from both the original 752 (event) message and the subsequent (follow-up) message. In a similar 753 fashion, each 2-step node needs to wait for the related follow-up 754 message, if there is one, in order to update that follow-up message 755 (as opposed to creating a new one. Hence the first node that uses 756 2-step mode MUST do two things: 758 1. Mark the original event message to indicate that a follow-up 759 message will be forthcoming (this is necessary in order to 761 Let any subsequent 2-step node know that there is already a 762 follow-up message, and 764 Let the end-point know to wait for a follow-up message; 766 2. Create a follow-up message in which to put the RTM determined as 767 an initial correctionField value. 769 IEEE 1588v2 [IEEE.1588.2008] defines this behavior for PTP messages. 771 Thus, for example, with reference to the PTP protocol, the PTPType 772 field identifies whether the message is a Sync message, Follow_up 773 message, Delay_Req message, or Delay_Resp message. The 10 octet long 774 Port ID field contains the identity of the source port, that is, the 775 specific PTP port of the boundary clock connected to the MPLS 776 network. The Sequence ID is the sequence ID of the PTP message 777 carried in the Value field of the message. 779 PTP messages also include a bit that indicates whether or not a 780 follow-up message will be coming. This bit, once it is set by a 781 2-step mode device, MUST stay set accordingly until the original and 782 follow-up messages are combined by an end-point (such as a Boundary 783 Clock). 785 Thus, an RTM packet, containing residence time information relating 786 to an earlier packet, also contains information identifying that 787 earlier packet. 789 For compatibility with PTP, RTM (when used for PTP packets) must 790 behave in a similar fashion. To do this, a 2-step RTM capable egress 791 interface will need to examine the S-bit in the Flags field of the 792 PTP sub-TLV (for RTM messages that indicate they are for PTP) and - 793 if it is clear (set to zero), it MUST set it and create a follow-up 794 PTP Type RTM message. If the S bit is already set, then the RTM 795 capable node MUST wait for the RTM message with the PTP type of 796 follow-up and matching originator and sequence number to make the 797 corresponding residence time update to the Scratch Pad field. 799 In practice an RTM operating according to two-step clock behaves like 800 a two-steps transparent clock. 802 A 1-step capable RTM node MAY elect to operate in either 1-step mode 803 (by making an update to the Scratch Pad field of the RTM message 804 containing the PTP even message), or in 2-step mode (by making an 805 update to the Scratch Pad of a follow-up message when its presence is 806 indicated), but MUST NOT do both. 808 Two main subcases can be identified for an RTM node operating as a 809 two-step clock: 811 A) If any of the previous RTM capable node or the previous PTP clock 812 (e.g. the BC connected to the first node), is a two-step clock, the 813 residence time is added to the RTM packet that has been created to 814 include the associated PTP packet (i.e. follow-up message in the 815 downstream direction), if the local RTM-capable node is also 816 operating as a two-step clock. This RTM packet carries the related 817 accumulated residence time and the appropriate values of the Sequence 818 Id and Port Id (the same identifiers carried in the packet processed) 819 and the Two-step Flag set to 1. 821 Note that the fact that an upstream RTM-capable node operating in the 822 two-step mode has created a follow-up message does not require any 823 subsequent RTM capable node to also operate in the 2-step mode, as 824 long as that RTM-capable node forwards the follow-up message on the 825 same LSP on which it forwards the corresponding previous message. 827 A one-step capable RTM node MAY elect to update the RTM follow-up 828 message as if it were operating in two-step mode, however, it MUST 829 NOT update both messages. 831 A PTP event packet (sync) is carried in the RTM packet in order for 832 an RTM node to identify that residence time measurement must be 833 performed on that specific packet. 835 To handle the residence time of the Delay request message on the 836 upstream direction, an RTM packet must be created to carry the 837 residence time on the associated downstream Delay Resp message. 839 The last RTM node of the MPLS network in addition to update the 840 correctionField of the associated PTP packet, must also properly 841 handle the two-step flag of the PTP packets. 843 B) When the PTP network connected to the MPLS and RTM node, operates 844 in one-step clock mode, the associated RTM packet must be created by 845 the RTM node itself. The associated RTM packet including the PTP 846 event packet needs now to indicate that a follow up message will be 847 coming. 849 The last RTM node of the LSP, if it receives an RTM message with a 850 PTP payload indicating a follow-up message will be forthcoming, must 851 generate a follow-up message and properly set the two-step flag of 852 the PTP packets. 854 8. IANA Considerations 856 8.1. New RTM G-ACh 858 IANA is requested to reserve a new G-ACh as follows: 860 +-------+----------------------------+---------------+ 861 | Value | Description | Reference | 862 +-------+----------------------------+---------------+ 863 | TBA1 | Residence Time Measurement | This document | 864 +-------+----------------------------+---------------+ 866 Table 1: New Residence Time Measurement 868 8.2. New RTM TLV Registry 870 IANA is requested to create sub-registry in Generic Associated 871 Channel (G-ACh) Parameters Registry called "MPLS RTM TLV Registry". 872 All code points in the range 0 through 127 in this registry shall be 873 allocated according to the "IETF Review" procedure as specified in 874 [RFC5226] . Code points in the range 128 through 191 in this registry 875 shall be allocated according to the "First Come First Served" 876 procedure as specified in [RFC5226]. This document defines the 877 following new values RTM TLV type s: 879 +-----------+-------------------------------+---------------+ 880 | Value | Description | Reference | 881 +-----------+-------------------------------+---------------+ 882 | 0 | Reserved | This document | 883 | 1 | No payload | This document | 884 | 2 | PTPv2, Ethernet encapsulation | This document | 885 | 3 | PTPv2, IPv4 Encapsulation | This document | 886 | 4 | PTPv2, IPv6 Encapsulation | This document | 887 | 5 | NTP | This document | 888 | 6-127 | Unassigned | | 889 | 128 - 191 | Unassigned | | 890 | 192 - 254 | Private Use | This document | 891 | 255 | Reserved | This document | 892 +-----------+-------------------------------+---------------+ 894 Table 2: RTM TLV Type 896 8.3. New RTM Sub-TLV Registry 898 IANA is requested to create sub-registry in MPLS RTM TLV Registry, 899 requested in Section 8.2, called "MPLS RTM Sub-TLV Registry". All 900 code points in the range 0 through 127 in this registry shall be 901 allocated according to the "IETF Review" procedure as specified in 902 [RFC5226] . Code points in the range 128 through 191 in this registry 903 shall be allocated according to the "First Come First Served" 904 procedure as specified in [RFC5226]. . This document defines the 905 following new values RTM sub-TLV types: 907 +-----------+-------------+---------------+ 908 | Value | Description | Reference | 909 +-----------+-------------+---------------+ 910 | 0 | Reserved | This document | 911 | 1 | PTP 2-step | This document | 912 | 2-127 | Unassigned | | 913 | 128 - 191 | Unassigned | | 914 | 192 - 254 | Private Use | This document | 915 | 255 | Reserved | This document | 916 +-----------+-------------+---------------+ 918 Table 3: RTM Sub-TLV Type 920 8.4. RTM Capability sub-TLV in OSPFv2 922 IANA is requested to assign a new type for RTM Capability sub-TLV 923 from OSPFv2 Extended Link TLV Sub-TLVs registry as follows: 925 +-------+----------------+---------------+ 926 | Value | Description | Reference | 927 +-------+----------------+---------------+ 928 | TBA2 | RTM Capability | This document | 929 +-------+----------------+---------------+ 931 Table 4: RTM Capability sub-TLV 933 8.5. IS-IS RTM Application ID 935 IANA is requested to assign a new Application ID for RTM from the 936 Application Identifiers for TLV 251 registry as follows: 938 +-------+-------------+---------------+ 939 | Value | Description | Reference | 940 +-------+-------------+---------------+ 941 | TBA3 | RTM | This document | 942 +-------+-------------+---------------+ 944 Table 5: IS-IS RTM Application ID 946 8.6. RTM_SET Sub-object RSVP Type and sub-TLVs 948 IANA is requested to assign a new Type for RTM_SET sub-object from 949 Attributes TLV Space sub-registry as follows: 951 +-----+------------+-----------+---------------+---------+----------+ 952 | Typ | Name | Allowed | Allowed on | Allowed | Referenc | 953 | e | | on LSP_A | LSP_REQUIRED_ | on LSP | e | 954 | | | TTRIBUTES | ATTRIBUTES | Hop Att | | 955 | | | | | ributes | | 956 +-----+------------+-----------+---------------+---------+----------+ 957 | TBA | RTM_SET | Yes | No | No | This | 958 | 4 | sub-object | | | | document | 959 +-----+------------+-----------+---------------+---------+----------+ 961 Table 6: RTM_SET Sub-object Type 963 IANA requested to create new sub-registry for sub-TLV types of 964 RTM_SET sub-object. All code points in the range 0 through 127 in 965 this registry shall be allocated according to the "IETF Review" 966 procedure as specified in [RFC5226] . Code points in the range 128 967 through 191 in this registry shall be allocated according to the 968 "First Come First Served" procedure as specified in [RFC5226]. This 969 document defines the following new values of RTM_SET object sub- 970 object types: 972 +-----------+----------------------+---------------+ 973 | Value | Description | Reference | 974 +-----------+----------------------+---------------+ 975 | 0 | Reserved | This document | 976 | 1 | IPv4 address | This document | 977 | 2 | IPv6 address | This document | 978 | 3 | Unnumbered interface | This document | 979 | 4-127 | Unassigned | | 980 | 128 - 191 | Unassigned | | 981 | 192 - 254 | Private Use | This document | 982 | 255 | Reserved | This document | 983 +-----------+----------------------+---------------+ 985 Table 7: RTM_SET object sub-object types 987 8.7. RTM_SET Attribute Flag 989 IANA is requested to assign new flag from Attribute Flags registry 991 +-----+--------+-----------+------------+-----+-----+---------------+ 992 | Bit | Name | Attribute | Attribute | RRO | ERO | Reference | 993 | No | | Flags | Flags Resv | | | | 994 | | | Path | | | | | 995 +-----+--------+-----------+------------+-----+-----+---------------+ 996 | TBA | RTM_SE | Yes | Yes | No | No | This document | 997 | 5 | T | | | | | | 998 +-----+--------+-----------+------------+-----+-----+---------------+ 1000 Table 8: RTM_SET Attribute Flag 1002 8.8. New Error Codes 1004 IANA is requested to assign new Error Codes from Error Codes and 1005 Globally-Defined Error Value Sub-Codes registry 1007 +------------+--------------------+---------------+ 1008 | Error Code | Meaning | Reference | 1009 +------------+--------------------+---------------+ 1010 | TBA6 | Duplicate TLV | This document | 1011 | TBA7 | Duplicate sub-TLV | This document | 1012 | TBA8 | RTM_SET TLV Absent | This document | 1013 +------------+--------------------+---------------+ 1015 Table 9: New Error Codes 1017 9. Security Considerations 1019 Routers that support Residence Time Measurement are subject to the 1020 same security considerations as defined in [RFC5586] . 1022 In addition - particularly as applied to use related to PTP - there 1023 is a presumed trust model that depends on the existence of a trusted 1024 relationship of at least all PTP-aware nodes on the path traversed by 1025 PTP messages. This is necessary as these nodes are expected to 1026 correctly modify specific content of the data in PTP messages and 1027 proper operation of the protocol depends on this ability. 1029 As a result, the content of the PTP-related data in RTM messages that 1030 will be modified by intermediate nodes cannot be authenticated, and 1031 the additional information that must be accessible for proper 1032 operation of PTP 1-step and 2-step modes MUST be accessible to 1033 intermediate nodes (i.e. - MUST NOT be encrypted in a manner that 1034 makes this data inaccessible). 1036 While it is possible for a supposed compromised node to intercept and 1037 modify the G-ACh content, this is an issue that exists for nodes in 1038 general - for any and all data that may be carried over an LSP - and 1039 is therefore the basis for an additional presumed trust model 1040 associated with existing LSPs and nodes. 1042 The ability for potentially authenticating and/or encrypting RTM and 1043 PTP data that is not needed by intermediate RTM/PTP-capable nodes is 1044 for further study. 1046 Security requirements of time protocols are provided in RFC 7384 1047 [RFC7384]. 1049 10. Acknowledgements 1051 Authors want to thank Loa Andersson, Lou Berger and Acee Lindem for 1052 their thorough reviews, thoughtful comments and, most of, patience. 1054 11. References 1056 11.1. Normative References 1058 [IEEE.1588.2008] 1059 "Standard for a Precision Clock Synchronization Protocol 1060 for Networked Measurement and Control Systems", 1061 IEEE Standard 1588, July 2008. 1063 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1064 Requirement Levels", BCP 14, RFC 2119, 1065 DOI 10.17487/RFC2119, March 1997, 1066 . 1068 [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., 1069 and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP 1070 Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001, 1071 . 1073 [RFC3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links 1074 in Resource ReSerVation Protocol - Traffic Engineering 1075 (RSVP-TE)", RFC 3477, DOI 10.17487/RFC3477, January 2003, 1076 . 1078 [RFC4385] Bryant, S., Swallow, G., Martini, L., and D. McPherson, 1079 "Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for 1080 Use over an MPLS PSN", RFC 4385, DOI 10.17487/RFC4385, 1081 February 2006, . 1083 [RFC5085] Nadeau, T., Ed. and C. Pignataro, Ed., "Pseudowire Virtual 1084 Circuit Connectivity Verification (VCCV): A Control 1085 Channel for Pseudowires", RFC 5085, DOI 10.17487/RFC5085, 1086 December 2007, . 1088 [RFC5420] Farrel, A., Ed., Papadimitriou, D., Vasseur, JP., and A. 1089 Ayyangarps, "Encoding of Attributes for MPLS LSP 1090 Establishment Using Resource Reservation Protocol Traffic 1091 Engineering (RSVP-TE)", RFC 5420, DOI 10.17487/RFC5420, 1092 February 2009, . 1094 [RFC5586] Bocci, M., Ed., Vigoureux, M., Ed., and S. Bryant, Ed., 1095 "MPLS Generic Associated Channel", RFC 5586, 1096 DOI 10.17487/RFC5586, June 2009, 1097 . 1099 [RFC5905] Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch, 1100 "Network Time Protocol Version 4: Protocol and Algorithms 1101 Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010, 1102 . 1104 [RFC6423] Li, H., Martini, L., He, J., and F. Huang, "Using the 1105 Generic Associated Channel Label for Pseudowire in the 1106 MPLS Transport Profile (MPLS-TP)", RFC 6423, 1107 DOI 10.17487/RFC6423, November 2011, 1108 . 1110 [RFC6823] Ginsberg, L., Previdi, S., and M. Shand, "Advertising 1111 Generic Information in IS-IS", RFC 6823, 1112 DOI 10.17487/RFC6823, December 2012, 1113 . 1115 [RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W., 1116 Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute 1117 Advertisement", RFC 7684, DOI 10.17487/RFC7684, November 1118 2015, . 1120 11.2. Informative References 1122 [I-D.ietf-ospf-ospfv3-lsa-extend] 1123 Lindem, A., Mirtorabi, S., Roy, A., and F. Baker, "OSPFv3 1124 LSA Extendibility", draft-ietf-ospf-ospfv3-lsa-extend-10 1125 (work in progress), May 2016. 1127 [I-D.ietf-tictoc-1588overmpls] 1128 Davari, S., Oren, A., Bhatia, M., Roberts, P., and L. 1129 Montini, "Transporting Timing messages over MPLS 1130 Networks", draft-ietf-tictoc-1588overmpls-07 (work in 1131 progress), October 2015. 1133 [RFC4202] Kompella, K., Ed. and Y. Rekhter, Ed., "Routing Extensions 1134 in Support of Generalized Multi-Protocol Label Switching 1135 (GMPLS)", RFC 4202, DOI 10.17487/RFC4202, October 2005, 1136 . 1138 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 1139 IANA Considerations Section in RFCs", BCP 26, RFC 5226, 1140 DOI 10.17487/RFC5226, May 2008, 1141 . 1143 [RFC6374] Frost, D. and S. Bryant, "Packet Loss and Delay 1144 Measurement for MPLS Networks", RFC 6374, 1145 DOI 10.17487/RFC6374, September 2011, 1146 . 1148 [RFC7384] Mizrahi, T., "Security Requirements of Time Protocols in 1149 Packet Switched Networks", RFC 7384, DOI 10.17487/RFC7384, 1150 October 2014, . 1152 Authors' Addresses 1154 Greg Mirsky 1155 Ericsson 1157 Email: gregory.mirsky@ericsson.com 1158 Stefano Ruffini 1159 Ericsson 1161 Email: stefano.ruffini@ericsson.com 1163 Eric Gray 1164 Ericsson 1166 Email: eric.gray@ericsson.com 1168 John Drake 1169 Juniper Networks 1171 Email: jdrake@juniper.net 1173 Stewart Bryant 1174 Independent 1176 Email: stewart.bryant@gmail.com 1178 Alexander Vainshtein 1179 ECI Telecom 1181 Email: Alexander.Vainshtein@ecitele.com