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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 Internet Draft Lou Berger 2 Updates: 3471, 4202, 4203, 5307 (LabN) 3 Category: Standards Track Julien Meuric 4 Expiration Date: October 17, 2013 (France Telecom Orange) 6 April 17, 2013 8 Revised Definition of The GMPLS Switching Capability and Type Fields 10 draft-ietf-ccamp-swcaps-update-01.txt 12 Abstract 14 GMPLS provides control for multiple switching technologies, and 15 hierarchical switching within a technology. GMPLS routing and 16 signaling use common values to indicate switching technology type. 17 These values are carried in routing in the Switching Capability 18 field, and in signaling in the Switching Type field. While the 19 values used in these fields are the primary indicators of the 20 technology and hierarchy level being controlled, the values are 21 not consistently defined and used across the different 22 technologies supported by GMPLS. This document is intended to 23 resolve the inconsistent definition and use of the Switching 24 Capability and Type fields by narrowly scoping the meaning and use 25 of the fields. This document updates any document that uses the 26 GMPLS Switching Capability and Types fields, in particular RFC 27 3471, RFC 4202, RFC 4203, and RFC 5307. 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), its areas, and its working groups. Note that 36 other groups may also distribute working documents as Internet- 37 Drafts. 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 The list of current Internet-Drafts can be accessed at 45 http://www.ietf.org/1id-abstracts.html 47 The list of Internet-Draft Shadow Directories can be accessed at 48 http://www.ietf.org/shadow.html 50 This Internet-Draft will expire on October 17, 2013 52 Copyright and License Notice 54 Copyright (c) 2013 IETF Trust and the persons identified as the 55 document authors. All rights reserved. 57 This document is subject to BCP 78 and the IETF Trust's Legal 58 Provisions Relating to IETF Documents 59 (http://trustee.ietf.org/license-info) in effect on the date of 60 publication of this document. Please review these documents 61 carefully, as they describe your rights and restrictions with respect 62 to this document. Code Components extracted from this document must 63 include Simplified BSD License text as described in Section 4.e of 64 the Trust Legal Provisions and are provided without warranty as 65 described in the Simplified BSD License. 67 1. Introduction 69 Generalized Multi-Protocol Label Switching (GMPLS) provides control 70 for multiple switching technologies. It also supports hierarchical 71 switching within a technology. The original GMPLS Architecture, per 72 [RFC3945], included support for five types of switching capabilities. 73 An additional type was also been defined in [RFC6002]. The switching 74 types defined in these documents include: 75 1. Packet Switch Capable (PSC) 76 2. Layer-2 Switch Capable (L2SC) 77 3. Time-Division Multiplex Capable (TDM) 78 4. Lambda Switch Capable (LSC) 79 5. Fiber-Switch Capable (FSC) 80 6. Data Channel Switching Capable (DCSC) 82 Support for the original types was defined for routing in [RFC4202], 83 [RFC4203], and [RFC5307], where the types were represented in the 84 Switching Capability (Switching Cap) field. In general, hierarchy 85 within a type is addressed in a type-specific fashion and a single 86 Switching Capability field value is defined per type. The exception 87 to this is PSC which was assigned four values to indicate four levels 88 of hierarchy: PSC-1, PSC-2, PSC-3 and PSC-4. The same values used in 89 routing are defined for signaling in [RFC3471], and are carried in 90 the Switching Type field. Following the IANA registry, we refer to 91 the values used in the routing Switching Capability field and 92 signaling Switching Type field as Switching Types. 94 In general, a Switching Type does not indicate a specific data plane 95 technology, but rather this needs to be inferred from context. For 96 example L2SC was defined to cover Ethernet and ATM, and TDM was 97 defined to cover both SONET/SDH [RFC4606] and G.709 [RFC4328]. The 98 basic assumption was that different technologies of the same type 99 would never operate within the same control, i.e., signaling and 100 routing, domains. 102 The past approach in assignment of Switching Types has proven to be 103 problematic from two perspectives. The first issue is that some 104 examples of switching technologies have different levels of switching 105 that can be performed within the same technology. For example, there 106 are multiple types of Ethernet switching that may occur within a 107 provider network. The second issues is that the Switching Capability 108 field value is used in Interior Gateway Protocols (IGPs) to indicate 109 the format of the Switching Capability-specific information (SCSI) 110 field, and that an implicit mapping of type to SCSI format is 111 impractical for implementations that support multiple switching 112 technologies. These issues led to the introduction of two new types 113 for Ethernet in [RFC6004] and [RFC6060], namely: 114 7. Ethernet Virtual Private Line (EVPL) 115 8. 802_1 PBB-TE (Provider Backbone Bridge - Traffic Engineering) 117 An additional value is also envisioned to be assigned in support of 118 G.709v3 by [GMPLS-G709] in order to disambiguate the format of the 119 SCSI field. 121 While a common representation of hierarchy levels within a switching 122 technology certainly fits the design objectives of GMPLS, the 123 definition of multiple PSC Switching Types has also proven to be of 124 little value. Notably, there are no known uses of PSC-2, PSC-3 and 125 PSC-4. 127 This document proposes to resolve such inconsistent definitions and 128 uses of the Switching Types by reducing the scope of the related 129 fields and narrowing their use. In particular this document proposes 130 deprecating the use of the Switching Types as an identifier of 131 hierarchy levels within a switching technology, and limit its use to 132 identification of a per-switching technology SCSI field format. 134 This document updates any document that uses the GMPLS Switching 135 Capability and Switching Type fields, in particular RFCs 3471, 4202, 136 4203, and 5307. 138 1.1. Current Switching Type Definition 140 The Switching Type values are carried in both routing and signaling 141 protocols. Values are identified in the IANA GMPLS Signaling 142 Parameters Switching Type registry, which is currently located at 143 http://www.iana.org/assignments/gmpls-sig-parameters/gmpls-sig- 144 parameters.xml 146 For routing, a common information element is defined to carry 147 switching type values for both OSPF and IS-IS routing protocols in 148 [RFC4202]. Per [RFC4202], switching type values are carried in a 149 Switching Capability (Switching Cap) field in an Interface Switching 150 Capability Descriptor. This information shares a common formatting 151 in both OSPF, as defined by [RFC4203], and in IS-IS, as defined by 152 [RFC5307]: 154 0 1 2 3 155 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 1 156 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 157 | Switching Cap | Encoding | Reserved | 158 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 159 ... 160 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 161 | Switching Capability-specific information | 162 | (variable) | 163 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 165 and 167 The content of the Switching Capability-specific information field 168 depends on the value of the Switching Capability field. 170 Similarly, the Switching Type field is defined as part of a common 171 format for use by GMPLS signaling protocols in [RFC3471] and is used 172 by [RFC3473]: 174 0 1 2 3 175 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 1 176 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 177 | LSP Enc. Type |Switching Type | G-PID | 178 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 180 Switching Type: 8 bits 182 Indicates the type of switching that should be performed on a 183 particular link. This field is needed for links that advertise 184 more than one type of switching capability. This field should 185 map to one of the values advertised for the corresponding link 186 in the routing Switching Capability Descriptor ... 188 1.2. Conventions Used In This Document 190 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 191 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 192 document are to be interpreted as described in [RFC2119]. 194 2. Revised Switching Type Definition 196 This document modifies the definition of Switching Type. The 197 definitions are slightly different for routing and signaling and are 198 described in the following sections. 200 2.1. Routing -- Switching Cap Field 202 For routing, i.e., [RFC4202], [RFC4203], and [RFC5307], the following 203 definition should be used for Switching Cap field: 205 The Switching Cap field indicates the type of switching being 206 advertised via GMPLS Switching Type values. A different Switching 207 Type value SHOULD be used for each data plane technology even when 208 those technologies share the same type of multiplexing or 209 switching. For example, Time Division Multiplexing (TDM) 210 technologies that have different multiplexing structures, such as 211 SDH [G.707] and OTN [G.709], should use two different Switching 212 Types. 214 As the format of the Switching Capability-specific information 215 field is dependent on the value of this field, a different 216 Switching Type value MUST be used to differentiate between 217 different Switching Capability-specific information field formats. 219 This definition does not modify the format of the Interface 220 Switching Capability Descriptor. 222 Note that from a practical standpoint, this means that any time a new 223 switching technology might use a different Switching Capability- 224 specific information field format, that a new Switching Type SHOULD 225 be used. 227 2.2. Signaling -- Switching Type Field 229 For signaling, i.e., [RFC3471] which is used by [RFC3473], the 230 following definition should be used for Switching Type field: 232 Indicates the type of switching that should be performed on a 233 particular link via GMPLS Switching Type values. This field maps 234 to one of the values advertised for the corresponding link in the 235 routing Switching Capability Descriptor, see [RFC4203] and 236 [RFC5307]. 238 Note that from a practical standpoint, there is no change in the 239 definition of this field. 241 2.3. Assigned Switching Types 243 This document deprecates the following Switching Types: 245 Value Name 246 2 Packet-Switch Capable-2 (PSC-2) 247 3 Packet-Switch Capable-3 (PSC-3) 248 4 Packet-Switch Capable-4 (PSC-4) 250 These values SHOULD NOT be treated as reserved values, i.e., 251 SHOULD NOT be generated and SHOULD be ignored upon receipt. 253 3. Compatibility 255 For existing implementations, the primary impact of this document is 256 deprecating the use of PSC-2, 3 and 4. At the time of publication, 257 there are no known deployments (or even implementations) that make 258 use of these values so there is no compatibility issues for current 259 routing and signaling implementations. 261 4. Security Considerations 263 This document impacts the values carried in a single field in 264 signaling and routing. As no new protocol formats or mechanisms are 265 defined, there are no particular security implications raised by this 266 document. 268 For a general discussion on MPLS and GMPLS related security issues, 269 see the MPLS/GMPLS security framework [RFC5920]. 271 5. IANA Considerations 273 IANA needs to deprecate and redefine the registry. In particular the 274 Switching Types portion of the Generalized Multi-Protocol Label 275 Switching (GMPLS) Signaling Parameters should be revised to read: 277 Switching Types 279 Registration Procedures 281 Standards Action 283 Reference 284 [RFC3471][RFC4328][This.draft] 286 Value Name Reference 287 0 Unassigned 288 1 Packet-Switch Capable-1 (PSC-1) [RFC3471] 289 2 Deprecated [This.draft] 290 3 Deprecated [This.draft] 291 4 Deprecated [This.draft] 292 5-29 Unassigned 293 30 Ethernet Virtual Private Line (EVPL) [RFC6004] 294 31-39 Unassigned 295 40 802_1 PBB-TE [RFC6060] 296 41-50 Unassigned 297 51 Layer-2 Switch Capable (L2SC) [RFC3471] 298 52-99 Unassigned 299 100 Time-Division-Multiplex Capable (TDM) [RFC3471] 300 101-124 Unassigned 301 125 Data Channel Switching Capable (DCSC) [RFC6002] 302 126-149 Unassigned 303 150 Lambda-Switch Capable (LSC) [RFC3471] 304 151-199 Unassigned 305 200 Fiber-Switch Capable (FSC) [RFC3471] 306 201-255 Unassigned 308 6. Acknowledgments 310 We thank John Drake for highlighting the current inconsistent 311 definitions associated with the Switching Capability and Type Fields. 312 Daniele Ceccarelli provided valuable feedback on this document. 314 7. References 316 7.1. Normative References 318 [RFC2119] Bradner, S., "RFC Key Words Key words for use in RFCs to 319 Indicate Requirement Levels", RFC 2119, March 1997. 321 [RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching 322 (GMPLS) Signaling Functional Description", RFC 3471, 323 January 2003. 325 [RFC4202] Kompella, K., Rekhter, Y., "Routing Extensions in 326 Support of Generalized Multi-Protocol Label Switching 327 (GMPLS)", RFC 4202, October 2005. 329 [RFC4203] Kompella, K., Rekhter, Y., "OSPF Extensions in Support 330 of Generalized Multi-Protocol Label Switching (GMPLS)", 331 RFC 4203, October 2005. 333 [RFC5307] Kompella, K., Rekhter, Y., "IS-IS Extensions in Support 334 of Generalized Multi-Protocol Label Switching (GMPLS)", 335 RFC 5307, October 2008. 337 7.2. Informative References 339 [G.707] ITU-T Recommendation G.707/Y.1322 (2007), "Network node 340 interface for the synchronous digital hierarchy (SDH)". 342 [G.709] ITU-T Recommendation G.709/Y.1331 (2009), "Interfaces for 343 the Optical Transport Network (OTN)". 345 [GMPLS-G709] Zhang, F., Li, D., Li, H., Belotti, S., Ceccarelli, 346 D., "Framework for GMPLS and PCE Control of G.709 347 Optical Transport Networks", work in progress, 348 draft-ietf-ccamp-gmpls-g709-framework. 350 [RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching 351 (GMPLS) Signaling Resource ReserVation Protocol-Traffic 352 Engineering (RSVP-TE) Extensions", RFC 3473, January 353 2003. 355 [RFC3945] Mannie, E., "Generalized Multi-Protocol Label Switching 356 (GMPLS) Architecture", RFC 3945, October 2004. 358 [RFC4328] Papadimitriou, D., "Generalized Multi-Protocol Label 359 Switching (GMPLS) Signaling Extensions for G.709 Optical 360 Transport Networks Control", RFC 4328, January 2006. 362 [RFC4606] Mannie, E., Papadimitriou, D., "Generalized 363 Multi-Protocol Label Switching (GMPLS) Extensions for 364 Synchronous Optical Network (SONET) and Synchronous 365 Digital Hierarchy (SDH) Control", RFC 4606, August 2006. 367 [RFC5920] Fang, L., "Security Framework for MPLS and GMPLS 368 Networks", RFC 5920, July 2010. 370 [RFC6002] Berger, L., Fedyk, D., "Generalized MPLS (GMPLS) Data 371 Channel Switching Capable (DCSC) and Channel Set Label 372 Extensions", RFC 6002, October 2010. 374 [RFC6004] Berger, L., Fedyk, D., "Generalized MPLS (GMPLS) Support 375 for Metro Ethernet Forum and G.8011 Ethernet Service 376 Switching", RFC 6004, front 2010. 378 [RFC6060] Fedyk, D., Shah, H., Bitar, N., Takacs, A., "Generalized 379 Multiprotocol Label Switching (GMPLS) Control of 380 Ethernet Provider Backbone Traffic Engineering 381 (PBB-TE)", RFC 6060, March 2011. 383 8. Authors' Addresses 385 Lou Berger 386 LabN Consulting, L.L.C. 387 Phone: +1 301 468 9228 388 Email: lberger@labn.net 390 Julien Meuric 391 France Telecom Orange 392 Research & Development 393 2, Avenue Pierre Marzin 394 22307 Lannion Cedex - France 395 Phone: +33 2 96 05 28 28 396 Email: julien.meuric@orange.com 398 Generated on: Wed, Apr 17, 2013 5:20:51 PM