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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 CCAMP Working Group Haomian Zheng 2 Internet-Draft Italo Busi 3 Intended status: Standards Track Huawei 4 Zafar Ali 5 Cisco 6 Sergio Belotti 7 Nokia 8 Daniele Ceccarelli 9 Ericsson 10 Daniel King 11 Lancaster University 13 Expires: September 6, 2017 March 6, 2017 15 Framework for GMPLS Control of Optical Transport Networks in G.709 16 Edition 5 18 draft-zheng-ccamp-gmpls-g709v5-fwk-00.txt 20 Abstract 22 The International Telecommunication Union Telecommunication 23 Standardization Sector (ITU-T) has extended its Recommendations 24 Optical Transport Networks (OTNs, G.709) to edition 5 to support new 25 features, including beyond 100 Gbps (B100G) OTN containers. 27 This document summarizes the architecture and requirements, and 28 provides corresponding control plane considerations to guide 29 protocol extensions development in support of OTNv5 control 30 mechanisms. 32 Status of this Memo 34 This Internet-Draft is submitted to IETF in full conformance with 35 the provisions of BCP 78 and BCP 79. 37 Internet-Drafts are working documents of the Internet Engineering 38 Task Force (IETF), its areas, and its working groups. Note that 39 other groups may also distribute working documents as Internet- 40 Drafts. 42 Internet-Drafts are draft documents valid for a maximum of six 43 months and may be updated, replaced, or obsoleted by other documents 44 at any time. It is inappropriate to use Internet-Drafts as 45 reference material or to cite them other than as "work in progress." 46 The list of current Internet-Drafts can be accessed at 47 http://www.ietf.org/ietf/1id-abstracts.txt. 49 The list of Internet-Draft Shadow Directories can be accessed at 50 http://www.ietf.org/shadow.html. 52 This Internet-Draft will expire on September 6, 2017. 54 Copyright Notice 56 Copyright (c) 2017 IETF Trust and the persons identified as the 57 document authors. All rights reserved. 59 This document is subject to BCP 78 and the IETF Trust's Legal 60 Provisions Relating to IETF Documents 61 (http://trustee.ietf.org/license-info) in effect on the date of 62 publication of this document. Please review these documents 63 carefully, as they describe your rights and restrictions with 64 respect to this document. Code Components extracted from this 65 document must include Simplified BSD License text as described in 66 Section 4.e of the Trust Legal Provisions and are provided without 67 warranty as described in the Simplified BSD License. 69 Table of Contents 71 1. Introduction ................................................. 3 72 1.1. Scope ................................................... 3 73 2. Terminology .................................................. 3 74 2.1. Conventions Used in this Document ....................... 3 75 2.2. OTN Related Terminologies in this Document .............. 3 76 3. Optical Transport Network Version 5 Overview ................. 4 77 3.1. OTN B100G Network ....................................... 4 78 3.1.1. Client Signal Mapping .............................. 4 79 3.1.2. Supporting clients signals with ODUCn .............. 5 80 3.2. MSI of ODUCn ............................................ 6 81 3.3. OTUCn sub rates (OTUCn-M) ............................... 7 82 4. Connection Management of ODUCn ............................... 7 83 5. GMPLS Implications ........................................... 8 84 5.1. Implications for GMPLS Signaling ........................ 8 85 5.2. Implications for GMPLS Routing .......................... 8 86 6. Security Considerations ...................................... 9 87 7. Contributors' Addresses ..................................... 10 88 8. References .................................................. 10 89 8.1. Normative References ................................... 10 90 8.2. Informative References ................................. 11 91 Authors' Addresses ............................................. 11 93 1. Introduction 95 ITU-T G.709v3, published in 2012, defined the interfaces to Optical 96 Transport Network (OTN), supporting a variety of Optical Data Unit 97 (ODU) containers up to 100 Gbps and flexible multiplexing hierarchy. 98 The OTN control plane framework was described in [RFC7062], 99 corresponding signaling and routing extensions were further 100 specified in [RFC7139] and [RFC7138] respectively. Furthermore, 101 there were additional updates made to G.709v4, resulting in 102 additional extensions which are described in [RFC7892] and [RFC7963]. 104 To meet the increasing demand for higher client bit rates, Edition 5 105 of G.709 [ITU-T G.709v5] has been released to provide beyond 100G 106 capabilities by introducing an ODUCn layer, which contains an 107 optical payload unit(OPUCn). 109 This document reviews relevant aspects of beyond 100 Gbps (B100G) 110 OTN technology and how it impacts current GMPLS control-plane 111 protocols. It highlights new considerations and proposes how to 112 update the mechanisms described in [RFC7062] to meet B100G control 113 plane requirements. 115 1.1. Scope 117 For the purposes of the B100G control plane discussion, the OTN 118 should be considered as a combination of the current OTN ODUk/Cn and 119 the wavelength optical layer. This document focuses on only the 120 control of the ODUk/ODUCn layer. The optical layer control will be 121 addressed in a separate document. 123 2. Terminology 125 2.1. Conventions Used in this Document 127 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 128 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 129 document are to be interpreted as described in RFC-2119 [RFC2119]. 131 2.2. OTN Related Terminologies in this Document 133 Terminologies from section 2 of [RFC7062] are reused in this 134 document, with the following additional terminologies defined in 135 [ITU-T G.709v5] used in this document: 137 ODUCn: Optical Data Unit - Cn 138 OPUCn: Optical Payload Unit- Cn 140 OTUCn: completely standardized Optical Transport Unit-Cn 142 3. Optical Transport Network Version 5 Overview 144 This section provides an overview of new features provided by 145 G.709v5 Optical Transport Network. 147 3.1. OTN B100G Network 149 3.1.1. Client Signal Mapping 151 +-----------------------+-----------------------------------+ 152 | ODU Type | ODU nominal bit rate | 153 +-----------------------+-----------------------------------+ 154 | ODU0 | 1,244,160 Kbps | 155 | ODU1 | 239/238 x 2,488,320 Kbps | 156 | ODU2 | 239/237 x 9,953,280 Kbps | 157 | ODU3 | 239/236 x 39,813,120 Kbps | 158 | ODU4 | 239/227 x 99,532,800 Kbps | 159 | ODUCn | n x 239/226 x 99,532,800 Kbps | 160 | | | 161 | ODUflex for | | 162 |Constant Bit Rate (CBR)| 239/238 x client signal bit rate | 163 | Client signals | | 164 | | | 165 | ODUflex for Generic | | 166 | Framing Procedure | Configured bit rate | 167 | - Framed (GFP-F) | | 168 | Mapped client signal | | 169 +-----------------------+-----------------------------------+ 171 Table 1: ODU Types and Bit Rates 173 NOTE: The nominal ODUCn rates are approximately n x 105,258,138.053 174 kbit/s. 176 Furthermore, and per [ITU-T G.709v5], the tolerance of ODUCn is +/- 177 20 ppm. The frame period for ODUCn is 1.163 s. Additionally, it 178 defined 5 Gbps tributary slots for ODU Cn. The number of tributary 179 slots (TS) defined in [ITU-T G.709v5] for each ODU are shown in 180 Table 2. 182 +------------+-------------------------------------+ 183 | | Nominal TS capacity | 184 | ODU Server +-------------------------------------+ 185 | | 1.25 Gbit/s | 2.5 Gbit/s | 5 Gbit/s | 186 +------------+-------------+------------+----------+ 187 | ODU0 | 1 | N/A | N/A | 188 +------------+-------------+------------+----------+ 189 | ODU1 | 2 | N/A | N/A | 190 +------------+-------------+------------+----------+ 191 | ODU2 | 8 | 4 | N/A | 192 +------------+-------------+------------+----------+ 193 | ODU3 | 32 | 16 | N/A | 194 +------------+-------------+------------+----------+ 195 | ODU4 | 80 | N/A | N/A | 196 +------------+-------------+------------+----------+ 197 | ODUCn | N/A | N/A | 20*n | 198 +------------+-------------+------------+----------+ 200 Table 2: Number of tributary slots (TS) 202 3.1.2. Supporting clients signals with ODUCn 204 According to [ITU-T G.709v5], various client signals can be mapped 205 to be supported by ODUCn. Typical client signal includes Ethernet, 206 MPLS and IP. The signal hierarchies can be found in Figure 1. 208 Client (e.g., IP, Ethernet, MPLS, ...) 210 | 212 OTN client signals (ODUk) 214 | 216 ODUCn 217 | 219 OTUCn 221 Figure 1: Mapping Client Signal to ODUCn 223 Packet streams (e.g., Ethernet, MPLS, IP) which are encapsulated 224 with the generic framing procedure is considered as the client and 225 can be carried by OTN client signals (known as ODUk, including 226 ODU0~4 and ODUflex). Then the OTN client signals will be further 227 mapped into ODUCn containers and multiplexed into OTUCn. It is worth 228 noting that the maximum bit rate for ODUk is 100G (ODU4), which is 229 the same rate of ODUC1. The mapping from ODU client signal to ODU 230 Containers is also required when ODU4 is multiplexed into ODUC1. 232 Examples of multiplexing can be found as follow: 234 - ODU0/ ODU1/ ODU2/ ODU3/ ODU4 into ODUC1 multiplexing with 235 5Gbps TS granularity: ODU0/ ODU1/ ODU2/ ODU3/ ODU4 occupies 236 1/1/2/8/20 of the 20 TSs for ODUC1. It is worth noting that for ODU0 237 and ODU1, the 5G TS is only partially occupied. 239 The type of the transported payload, encoded as the payload type, is 240 set to 22 for ODUCn. 242 3.2. MSI of ODUCn 244 When multiplexing an OTN client signal into ODUCn, [ITU-T G.709v5] 245 specifies the information that must be transported in-band to 246 correctly demultiplexing the signal. MSI is used to specify the 247 identifier of each multiplexing section. The MSI information is 248 located in the mapping specific area of the PSI signal and is local 249 to each link. 251 The MSI information is organized as a set of entries, with n 252 entries for each OPUC TS. The MSI has a fixed length of 40n bytes 253 and indicates the ODTU content of each tributary slot (TS) of an 254 OPUCn. 256 Two bytes are used for each tributary slot. The information carried 257 by each entry is: 259 - TS availability bit 1 indicates if the tributary slot is 260 available or unavailable. 262 - The TS occupation bit 9 indicates if the tributary slot is 263 allocated or unallocated. 265 - The tributary port number in bits 2 to 8 and 10 to 16 indicates 266 the port number of the ODTUCn.ts that is being transported in this 267 TS; a flexible assignment of tributary port to tributary slots is 268 possible. ODTUC.ts tributary ports are numbered 1 to 10n. The value 269 is set to all-0s when the occupation bit has the value 0 (tributary 270 slot is unallocated). 272 Tributary Port Number (TPN) indicates the port number of the OTN 273 client signal transported by the ODUCn. The TPN is the same for all 274 the TSs assigned to the transport of the same OTN client signal. 276 3.3. OTUCn sub rates (OTUCn-M) 278 An OTUCn with a bit rate that is not an integer multiple of 100 279 Gbit/s can be described as an OTUCn-M. An OTUCn-M frame contains n 280 instances of OTUC overhead, ODUC overhead and OPUC overhead together 281 with M 5Gbit/s OPUCn TS. 283 When an OTUCn-M is used to carry an ODUCn (20n-M) TS are marked as 284 unavailable, in the OPUCn multiplex structure identifier (MSI), 285 since they cannot be used to carry a client signal. 287 4. Connection Management of ODUCn 289 ODUk based connection management has been described in section 4 of 290 [RFC7062]. In this section the connection management of ODUCn is 291 described, which is independent but used together with ODUk based 292 connection management. 294 ODUCn based connection management is concerned with controlling the 295 connectivity of ODUCn paths. According to ITU-T G.872, the 296 intermediate nodes with ODUCn do not support the switching of ODUCn 297 time slot. Intermediate ODUCn points are only considered as a 298 forwarding node. Once an ODUCn path is used to transport client 299 signal, the TS occupied will not change across the ODUCn network. 301 5. GMPLS Implications 303 5.1. Implications for GMPLS Signaling 305 For OTNv3 network control, [RFC7139] defines RSVP-TE signaling 306 extensions, extending the base specifications [RFC3473] and 307 [RFC4328]. 309 As described in Section 3, [ITU-T G.709v5] introduced some new 310 features including the ODUCn, OTUCn for beyond 100G control. The 311 mechanisms defined in [RFC7139] do not support such features, and 312 protocol extensions SHALL be necessary to allow them to be 313 controlled by a GMPLS control plane. In summary, the following new 314 signaling aspects SHOULD be considered: 316 - Support for specifying new signal types and related traffic 317 information: The traffic parameters should be extended in a 318 signaling message to support the new ODUCn; 320 - Support the new TS granularity: the signaling protocol should be 321 able to identify the TS granularity (i.e., the new 5 Gbps TS 322 granularity) to be used for establishing a Hierarchical LSP that 323 will be used to carry service LSP(s) requiring a specific TS 324 granularity. 326 - Support for LSP setup of new ODUCn containers with related 327 mapping and multiplexing capabilities: A new label format must be 328 defined to carry the exact TS's allocation information related to 329 the extended mapping and multiplexing hierarchy (for example, ODU4 330 into ODUCn multiplexing (with 5 Gbps TS granularity)), in order to 331 set up all the possible ODU connections. 333 - Support for TPN allocation and negotiation: TPN needs to be 334 configured as part of the MSI information (see more information in 335 Section 3.1.2.1). A signaling mechanism must be identified to carry 336 TPN information if the control plane is used to configure MSI 337 information. 339 - Support for LSP setup of OTUCn sub rates (OTUCn-M) path: based on 340 previous extensions, there should be new signal mechanism to declare 341 the OTUCn-m information. 343 5.2. Implications for GMPLS Routing 345 The path computation process needs to select a suitable route for an 346 ODUCn connection request. Evaluation of the available bandwidth on 347 each candidate link is required for path computation. The routing 348 protocol SHOULD be extended to carry sufficient information to 349 represent ODU Traffic Engineering (TE) topology. 351 The Interface Switching Capability Descriptors defined in [RFC4203] 352 present a new constraint for LSP path computation. [RFC4203] 353 defines the Switching Capability, related Maximum LSP Bandwidth, and 354 Switching Capability specific information. [RFC7138] updates the 355 ISCD to support ODU4, ODU2e and ODUflex. The new Switching 356 Capability specific information provided in [RFC7138] have to be 357 adapted to support new features contained in [ITU-T G.709v5]. The 358 following requirements should be considered: 360 - Support for carrying the link multiplexing capability: As 361 discussed in Section 3.1.2, many different types of ODUk can be 362 multiplexed into the ODUCn. For example, ODU4 may be multiplexed 363 into ODUC1. An OTUCn link may support one or more types of ODUk 364 signals. The routing protocol should be capable of carrying this 365 multiplexing capability. 367 - Support for additional Tributary Slot Granularity advertisement: 368 as new tributary slot granularity (5G TS) is introduced in [G.709 369 v5], there is a need to specify this parameter. 371 - Support for advertisement of OTUCn sub rates support information: 372 Given the same n value, there is possible different OTUCn sub rates. 373 Corresponding information should be defined in the routing mechanism 374 to satisfy this feature. 376 6. Security Considerations 378 TBD. 380 7. Contributors' Addresses 382 Xian Zhang 383 Huawei Technologies 384 Email: zhang.xian@huawei.com 386 Antonello Bonfanti 387 Cisco 388 Email: abonfant@cisco.com 390 Dieter Beller 391 Nokia 392 Email: Dieter.Beller@nokia.com 394 8. References 396 8.1. Normative References 398 [RFC2119] S. Bradner, "Key words for use in RFCs to indicate 399 requirements levels", RFC 2119, March 1997. 401 [ITU-T G.709v5] ITU-T, "Interface for the Optical Transport Network 402 (OTN)", G.709/Y.1331 Recommendation, June 2016. 404 [RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label 405 Switching (GMPLS) Signaling Resource ReserVation 406 Protocol-Traffic Engineering (RSVP-TE) Extensions", 407 RFC 3473, DOI 10.17487/RFC3473, January 2003, 409 [RFC4203] Kompella, K. and Y. Rekhter, "OSPF Extensions in Support 410 of Generalized Multi-Protocol Label Switching (GMPLS)", 411 RFC 4203, October 2005. 413 [RFC4328] Papadimitriou, D., Ed., "Generalized Multi-Protocol Label 414 Switching (GMPLS) Signaling Extensions for G.709 Optical 415 Transport Networks Control", RFC 4328, January 2006, 417 [RFC7138] D. Ceccarelli, F. Zhang, S. Belotti, R. Rao, J. Drake, 418 'Traffic Engineering Extensions to OSPF for GMPLS Control 419 of Evolving G.709 Optical Transport Networks', RFC7138, 420 March 2014. 422 [RFC7139] F. Zhang, G. Zhang, S. Belotti, D. Ceccarelli, K. Pithewan, 423 'GMPLS Signaling Extensions for Control of Evolving G.709 424 Optical Transport Networks', RFC7139, March 2014. 426 [RFC7892] Z. Ali, A. Bonfanti, M. Hartley, F. Zhang, 'IANA 427 Allocation Procedures for the GMPLS OTN Signal Type 428 Registry', RFC7892, May 2016. 430 8.2. Informative References 432 [RFC7062] F. Zhang, D. Li, H. Li, S. Belotti, D. Ceccarelli, 433 'Framework for GMPLS and PCE Control of G.709 Optical 434 Transport Networks', RFC 7062, November 2013. 436 [RFC7963] Z. Ali, A. Bonfanti, M. Hartley, F. Zhang, 'RSVP-TE 437 Extension for Additional Signal Types in G.709 Optical 438 Transport Networks (OTNs)', RFC7963, August 2016. 440 Authors' Addresses 442 Haomian Zheng 443 Huawei Technologies 444 Email: zhenghaomian@huawei.com 446 Italo Busi 447 Huawei Technologies 448 Email: Italo.Busi@huawei.com 450 Zafar Ali 451 Cisco 452 Email: zali@cisco.com 454 Sergio Belotti 455 Nokia 456 Email: sergio.belotti@nokia.com 458 Daniele Ceccarelli 459 Ericsson 460 Email: daniele.ceccarelli@ericsson.com 462 Daniel King 463 Lancaster University 464 Email: d.king@lancaster.ac.uk