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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-06) exists of draft-ietf-pwe3-mspw-er-02 ** Downref: Normative reference to an Informational RFC: RFC 3985 ** Obsolete normative reference: RFC 4447 (Obsoleted by RFC 8077) ** Downref: Normative reference to an Informational RFC: RFC 5659 ** Downref: Normative reference to an Informational RFC: RFC 6371 Summary: 4 errors (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group J. Dong 3 Internet-Draft M. Chen 4 Intended status: Standards Track Huawei Technologies 5 Expires: April 24, 2014 G. Mirsky 6 Ericsson 7 October 21, 2013 9 LDP Extensions for Lock Instruct and Loopback of Pseudowire in MPLS 10 Transport Profile 11 draft-dong-pwe3-mpls-tp-li-lb-05 13 Abstract 15 This document specifies extensions to the Label Distribution Protocol 16 (LDP) to support provisioning of lock instruct (LI) and loopback (LB) 17 mechanism for MPLS Transport Profile (MPLS-TP) pseudowires (PWs). 19 Requirements Language 21 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 22 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 23 document are to be interpreted as described in RFC 2119 [RFC2119]. 25 Status of This Memo 27 This Internet-Draft is submitted in full conformance with the 28 provisions of BCP 78 and BCP 79. 30 Internet-Drafts are working documents of the Internet Engineering 31 Task Force (IETF). Note that other groups may also distribute 32 working documents as Internet-Drafts. The list of current Internet- 33 Drafts is at http://datatracker.ietf.org/drafts/current/. 35 Internet-Drafts are draft documents valid for a maximum of six months 36 and may be updated, replaced, or obsoleted by other documents at any 37 time. It is inappropriate to use Internet-Drafts as reference 38 material or to cite them other than as "work in progress." 40 This Internet-Draft will expire on April 24, 2014. 42 Copyright Notice 44 Copyright (c) 2013 IETF Trust and the persons identified as the 45 document authors. All rights reserved. 47 This document is subject to BCP 78 and the IETF Trust's Legal 48 Provisions Relating to IETF Documents 49 (http://trustee.ietf.org/license-info) in effect on the date of 50 publication of this document. Please review these documents 51 carefully, as they describe your rights and restrictions with respect 52 to this document. Code Components extracted from this document must 53 include Simplified BSD License text as described in Section 4.e of 54 the Trust Legal Provisions and are provided without warranty as 55 described in the Simplified BSD License. 57 Table of Contents 59 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 60 2. LDP Extensions . . . . . . . . . . . . . . . . . . . . . . . 3 61 2.1. Extensions to MPLS-TP PW OAM Administration TLV . . . . . 3 62 2.2. Extensions to PW Status TLV . . . . . . . . . . . . . . . 3 63 3. Operations . . . . . . . . . . . . . . . . . . . . . . . . . 3 64 3.1. Lock Instruct . . . . . . . . . . . . . . . . . . . . . . 3 65 3.2. Loopback . . . . . . . . . . . . . . . . . . . . . . . . 4 66 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 67 5. Security Considerations . . . . . . . . . . . . . . . . . . . 6 68 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 69 6.1. Normative References . . . . . . . . . . . . . . . . . . 6 70 6.2. Informative References . . . . . . . . . . . . . . . . . 7 71 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 73 1. Introduction 75 The requirements for Lock Instruct (LI) and Loopback (LB) are 76 specified in [RFC5860], and the framework of LI and LB is specified 77 in [RFC6371]. [RFC6435] defines management plane based LI and LB 78 mechanisms, and an LI OAM message can be used for additional lock 79 coordination between the Maintenance Entity Group End Points (MEPs). 80 Management plane based LI and LB are suitable for scenarios where 81 dynamic control plane is not available. 83 When a dynamic control plane is used for establishing MPLS-TP 84 pseudowires (PWs), it's natural to use and extend the control plane 85 protocol for the provisioning of LI and LB functions. Unlike other 86 OAM mechanisms, LI and LB would modify the forwarding plane of a PW, 87 thus without the involvement of control plane this may result in 88 inconsistency between control plane and data plane. Besides, with 89 control plane based mechanism, it does not need to rely on the TTL 90 expiration to make the OAM requests reach particular Maintenance 91 Entity Group Intermediate Point (MIP) or MEP. 93 There are some existing control plane based OAM provisioning 94 mechanisms for MPLS-TP PWs. For example, [I-D.ietf-pwe3-oam-config] 95 specifies the LDP extensions for the configuration of proactive OAM 96 functions for MPLS-TP PWs when control plane is used. 98 This document defines mechanisms similar to 99 [I-D.ietf-pwe3-oam-config] to implement LI and LB functions for MPLS- 100 TP PWs when MPLS-TP control plane is used. The mechanisms defined in 101 this document are complementary to [RFC6435]. 103 2. LDP Extensions 105 2.1. Extensions to MPLS-TP PW OAM Administration TLV 107 Two new flags (Lock bit and Loopback bit) are defined in MPLS-TP PW 108 OAM Administration TLV [I-D.ietf-pwe3-oam-config]. 110 The format of the extended MPLS-TP PW OAM Administration TLV is as 111 below: 113 0 1 2 3 114 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 1 115 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 116 |0|0| Type (TBD) | Length | 117 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 118 |I|A|K|B| Reserved | 119 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 121 Lock (K): When this bit is set, it indicates that the T-PE needs to 122 enable "Lock" function for this PW. 124 Loopback (B): When this bit is set, it indicates that the target node 125 of this message SHOULD enable loopback function for this PW. 127 2.2. Extensions to PW Status TLV 129 Two new Status bits are defined in PW Status TLV: 131 Bit Mask Description 132 ==================================================================== 133 TBD1 Pseudowire in Lock Mode [this document] 134 TBD2 Pseudowire in Loopback Mode [this document] 136 3. Operations 138 The control plane based LI and LB functions are applicable to both 139 Single-Segment Pseudowire (SS-PW) [RFC3985] [RFC4447] and Multi- 140 Segment Pseudowire (MS-PW) [RFC5659] [RFC6073]. 142 3.1. Lock Instruct 143 When a PE/T-PE intends to put a PW into lock mode, it MUST send a 144 Mapping message with the Lock (K) bit in the MPLS-TP PW OAM 145 Administration TLV set. 147 For SS-PW, when the Mapping message arrives at the remote PE, the 148 receiving PE SHOULD try to take the PW out of service. If the 149 receiving PE locks the PW successfully, it SHOULD send a Notification 150 message with PW status "Pseudowire in Lock Mode". Otherwise, it 151 SHOULD send a Notification message with the LDP Status code set to 152 "PW Lock Failure". 154 For MS-PW, when the Mapping message arrives at a downstream S-PE, the 155 receiving S-PE SHOULD forward this Mapping message with the K bit 156 unchanged towards the remote T-PE. When the Mapping message arrives 157 at the remote T-PE, the receiving T-PE node SHOULD try to take the PW 158 out of service. If the receiving T-PE locks the PW successfully, it 159 SHOULD send a Notification message with PW status "Pseudowire in Lock 160 Mode" to the upstream S-PE. Otherwise, it SHOULD send a Notification 161 message with the LDP Status code set to "PW Lock Failure". On 162 receipt of the Notification message, the S-PEs would know whether the 163 MS-PW is in lock mode or not, and the S-PEs SHOULD forward the 164 Notification message back to the Source T-PE. 166 When the PE/T-PE intends to take the PW out of the lock mode, it MUST 167 send a Mapping message with the Lock (K) bit in the MPLS-TP PW OAM 168 Administration TLV cleared. The receiving PE/T-PE SHOULD try to 169 unlock the PW. If the PW is unlocked successfully, the receiving PE/ 170 T-PE SHOULD send a Notification message with PW status bit 171 "Pseudowire in Lock Mode" cleared. Otherwise, it SHOULD send a 172 Notification message with the LDP Status code set to "PW Unlock 173 Failure". 175 3.2. Loopback 177 When a PE/T-PE intends to put the remote PE/T-PE of a PW into 178 loopback mode, it MUST send a Mapping message with both the Lock (K) 179 bit and Loopback (B) bit in the MPLS-TP PW OAM Administration TLV 180 set. When a T-PE intends to put a particular S-PE of the MS-PW into 181 loopback mode, it MUST send a Mapping message with both the Lock (K) 182 bit and Loopback (B) bit set, and an Explicit Route Hop TLV(ER-Hop 183 TLV) [I-D.ietf-pwe3-mspw-er] identifying the Target S-PE node MUST be 184 carried in the Mapping message. The L flag in the ER-Hop TLV SHOULD 185 be cleared. To ensure that the ER-Hop TLV identifies a single node 186 as the Target S-PE, The PreLen field in the IPv4 prefix ER-Hop TLV 187 SHOULD be set to 32, the PreLen field in the IPv6 prefix ER-Hop TLV 188 SHOULD be set to 128, and the PreLen field in the L2 PW Address ER- 189 Hop TLV SHOULD be set to 96. Information of the S-PE node may be 190 collected using the SP-PE TLVs [RFC6073]. 192 When the Mapping message arrives at the remote PE/T-PE, the receiving 193 PE SHOULD try to put the PW in loopback mode. If the receiver node 194 puts the PW into loopback mode successfully, it SHOULD send a 195 Notification message with PW status "Pseudowire in Loopback Mode". 196 Otherwise, it SHOULD send a Notification message with the LDP Status 197 code set to "PW Enter Loopback Failure". 199 When a Mapping message with an ER-Hop TLV arrives an S-PE, the S-PE 200 SHOULD check the ER-Hop TLV to see if it is the target S-PE of the 201 message. If not, the S-PE SHOULD forward the message with the K and 202 B bit unchanged to the next hop S-PE. When the Mapping message 203 arrives at the target S-PE, the S-PE SHOULD parse the MPLS-TP PW OAM 204 Administration TLV and try to put the PW into loopback mode. If the 205 S-PE puts the PW into loopback mode successfully, it SHOULD send a 206 Notification message with PW status set to "Pseudowire in Loopback 207 Mode". An SP-PE TLV [RFC6073] identifying the S-PE in loopback mode 208 SHOULD also be carried in the Notification message. If the S-PE 209 fails to put the PW into loopback mode, it SHOULD send a Notification 210 message with the LDP Status code set to "PW Enter Loopback Failure". 211 An SP-PE TLV identifying this S-PE SHOULD also be carried in the 212 Notification message. 214 When the PE/T-PE intends to take the remote PE/T-PE out of the 215 loopback mode, it MUST send a Mapping message with the Lock (K) bit 216 set and Loopback (B) bit cleared. When the T-PE intends to take a 217 particular S-PE out of loopback mode, the message MUST also carry an 218 ER-Hop TLV to identify the target S-PE. If the PW is taken out of 219 loopback mode successfully on the receiving PE/T-PE/S-PE, it SHOULD 220 send a Notification message with PW status bit "Pseudowire in 221 Loopback Mode" cleared. Otherwise, it SHOULD send a Notification 222 message with the LDP Status code set to "PW Exit Loopback Failure". 223 For the S-PE case, An SP-PE TLV identifying this S-PE node SHOULD 224 also be carried in the Notification message. 226 4. IANA Considerations 228 Two bits "Lock" (K) and "Loopback" (B) as defined in section 2.1 need 229 to be allocated in the MPLS-TP PW OAM Administration TLV. 231 Two new PW Status bits as defined in section 2.2 need to be allocated 232 by IANA in the "Pseudowire Status Codes" registry. 234 Four new LDP status codes need to be assigned by IANA in the LDP 235 "Status Code Name Space" registry: 237 Range/Value E Description 238 TBA 0 PW Lock Failure 239 TBA 0 PW Unlock Failure 240 TBA 0 PW Enter Loopback Failure 241 TBA 0 PW Exit Loopback Failure 243 5. Security Considerations 245 This document introduces no new security considerations over 246 [RFC5036], [RFC4447] and [RFC6073]. 248 6. References 250 6.1. Normative References 252 [I-D.ietf-pwe3-mspw-er] 253 Dutta, P., Bocci, M., and L. Martini, "Explicit Path 254 Routing for Dynamic Multi-Segment Pseudowires", draft- 255 ietf-pwe3-mspw-er-02 (work in progress), December 2012. 257 [I-D.ietf-pwe3-oam-config] 258 Zhang, F., Bo, W., and E. Bellagamba, "Label Distribution 259 Protocol Extensions for Proactive Operations, 260 Administration and Maintenance Configuration of Dynamic 261 MPLS Transport Profile PseudoWire", draft-ietf-pwe3-oam- 262 config-01 (work in progress), August 2012. 264 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 265 Requirement Levels", BCP 14, RFC 2119, March 1997. 267 [RFC3985] Bryant, S. and P. Pate, "Pseudo Wire Emulation Edge-to- 268 Edge (PWE3) Architecture", RFC 3985, March 2005. 270 [RFC4447] Martini, L., Rosen, E., El-Aawar, N., Smith, T., and G. 271 Heron, "Pseudowire Setup and Maintenance Using the Label 272 Distribution Protocol (LDP)", RFC 4447, April 2006. 274 [RFC5036] Andersson, L., Minei, I., and B. Thomas, "LDP 275 Specification", RFC 5036, October 2007. 277 [RFC5659] Bocci, M. and S. Bryant, "An Architecture for Multi- 278 Segment Pseudowire Emulation Edge-to-Edge", RFC 5659, 279 October 2009. 281 [RFC5860] Vigoureux, M., Ward, D., and M. Betts, "Requirements for 282 Operations, Administration, and Maintenance (OAM) in MPLS 283 Transport Networks", RFC 5860, May 2010. 285 [RFC6073] Martini, L., Metz, C., Nadeau, T., Bocci, M., and M. 286 Aissaoui, "Segmented Pseudowire", RFC 6073, January 2011. 288 [RFC6371] Busi, I. and D. Allan, "Operations, Administration, and 289 Maintenance Framework for MPLS-Based Transport Networks", 290 RFC 6371, September 2011. 292 6.2. Informative References 294 [RFC6435] Boutros, S., Sivabalan, S., Aggarwal, R., Vigoureux, M., 295 and X. Dai, "MPLS Transport Profile Lock Instruct and 296 Loopback Functions", RFC 6435, November 2011. 298 Authors' Addresses 300 Jie Dong 301 Huawei Technologies 302 Huawei Building, No.156 Beiqing Rd. 303 Beijing 100095 304 China 306 Email: jie.dong@huawei.com 308 Mach(Guoyi) Chen 309 Huawei Technologies 310 Huawei Building, No.156 Beiqing Rd. 311 Beijing 100095 312 China 314 Email: mach.chen@huawei.com 316 Greg Mirsky 317 Ericsson 319 Email: gregory.mirsky@ericsson.com