Network Working Group J. Dong Internet-Draft M. Chen Intended status: Standards Track Huawei Technologies Expires: September 2, 2012 G. Mirsky Ericsson March 1, 2012 LDP Extensions for Lock Instruct and Loopback of Pseudowire in MPLS Transport Profile draft-dong-pwe3-mpls-tp-li-lb-00 Abstract This document specifies extensions to the Label Distribution Protocol (LDP) to support provisioning of lock instruct and loopback mechanism for MPLS-TP Pseudowires. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on September 2, 2012. Copyright Notice Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents Dong, et al. Expires September 2, 2012 [Page 1] Internet-Draft LDP Extensions for PW LI&LB March 2012 (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. LDP Extensions . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1. Extensions to MPLS-TP PW OAM Administration TLV . . . . . . 3 2.2. Extensions to PW Status TLV . . . . . . . . . . . . . . . . 4 3. Operations . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.1. Lock Instruct . . . . . . . . . . . . . . . . . . . . . . . 4 3.2. Loopback . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 7.1. Normative References . . . . . . . . . . . . . . . . . . . 6 7.2. Informative References . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 Dong, et al. Expires September 2, 2012 [Page 2] Internet-Draft LDP Extensions for PW LI&LB March 2012 1. Introduction The requirements of Lock Instruct (LI) and Loopback (LB) are specified in [RFC5860], and the framework of LI and LB is specified in [RFC6371]. [RFC6435] defines in-band Lock Instruct (LI) and Loopback (LB) functions, which leverages the Generic Associated Channel (GACH) and Generic Associated Channel Label (GAL) [RFC5586] and the management plane to perform LI function and use the management plane to perform LB function. In-band and Management based LI and LB is suitable for scenarios where control plane is not used. When a dynamic control plane is used for establishing MPLS-TP PWs, it's natural to use and extend the control plane protocol to provision LI and LB functions. Unlike other OAM mechanisms, LI and LB would modify the forwarding plane of a PW, thus without the involvement of control plane this may result in inconsistency between control plane and data plane. Besides, with control plane based mechanism, it does not need to rely on the TTL expiration to make the LI/LB requests to reach particular MIP or MEP. This document specifies extensions to LDP to implement LI and LB for MPLS-TP PWs when MPLS-TP control plane is used. The mechanisms defined in this document are complementary to [RFC6435]. 2. LDP Extensions 2.1. Extensions to MPLS-TP PW OAM Administration TLV Two new flags (Lock bit and Loopback bit) are defined in MPLS-TP PW OAM Administration TLV [I-D.ietf-pwe3-oam-config]. Format of extended MPLS-TP PW OAM Administration TLV is as below: 0 1 2 3 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0| Type (TBD) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |I|A|K|B| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Lock (K): When this bit is set, it indicates that the T-PE needs to enable "Lock" function for this PW. Loopback (B): When this bit is set, it indicates that the target node of this message SHOULD enable loopback function for this PW. Dong, et al. Expires September 2, 2012 [Page 3] Internet-Draft LDP Extensions for PW LI&LB March 2012 2.2. Extensions to PW Status TLV Two new Status bits are defined in PW Status TLV: Bit Mask Description ==================================================================== 0x00000020 Pseudowire in Lock Mode [this document] 0x00000040 Pseudowire in Loopback Mode [this document] 3. Operations The control plane based Lock Instruct and Loopback functions are applicable to both Single-Segment Pseudowire (SS-PW) [RFC3985] [RFC4447] and Multi-Segment Pseudowire (MS-PW) [RFC5659] [RFC6073]. 3.1. Lock Instruct When a PE/T-PE wants to put a PW in lock mode, it MUST send a Mapping message with the Lock (K) bit in the MPLS-TP PW OAM Administration TLV set. For SS-PW, when the Mapping message arrives at the remote PE, the receiving PE SHOULD try to take the PW out of service. If the receiving PE locks the PW successfully, it SHOULD sent a Notification message with PW status "Pseudowire in Lock Mode". Otherwise, it SHOULD send a Notification message with the LDP Status code set to "Lock Failure" , and the Status bit "Pseudowire in Lock Mode" MUST be cleared. For MS-PW, when the Mapping message arrives at a downstream S-PE, the receiving S-PE SHOULD forward this Mapping message downstream towards the remote T-PE. When the Mapping message arrives at the remote T-PE, it SHOULD try to take the PW out of service. If the receiving T-PE locks the PW successfully, it SHOULD send a Notification message with PW status "Pseudowire in Lock Mode" to the upstream S-PE. Otherwise, it SHOULD send a Notification message with the LDP Status code set to "Lock Failure" , and the Status bit "Pseudowire in Lock Mode" MUST be cleared. On receipt of the Notification message, the S-PEs would know whether the MS-PW is locked successfully, and the S-PEs SHOULD forward the Notification message back to the Source T-PE. When the PE/T-PE wants to take the PW out of the lock mode, it MUST send a Mapping message with the Lock (K) bit in the MPLS-TP PW OAM Administration TLV cleared. The receiving PE/T-PE SHOULD try to unlock the PW. If the PW is unlocked successfully, the receiving PE/ T-PE SHOULD send a Notification message with PW status bit "Pseudowire in Lock Mode" cleared. Otherwise, it SHOULD send a Dong, et al. Expires September 2, 2012 [Page 4] Internet-Draft LDP Extensions for PW LI&LB March 2012 Notification message with the LDP Status code set to "Unlock Failure", and the Status bit "Pseudowire in Lock Mode" MUST be set. 3.2. Loopback When a PE/T-PE wants to put the remote PE/T-PE of a PW into loopback mode, it MUST send a Mapping message with both the Lock (K) bit and Loopback (B) bit in the MPLS-TP PW OAM Administration TLV set. When a T-PE wants to put a particular S-PE of the PW into loopback mode, it MUST send a Mapping message with both the Lock (K) bit and Loopback (B) bit set, and a PW Switching Point PE TLV(SP-PE TLV) [RFC6073] identifying the Target S-PE SHOULD be carried in the Mapping message. When the Mapping message arrives at the remote PE/T-PE, the receiving PE SHOULD try to put the PW in loopback mode. If the receiver node puts the PW into loopback mode successfully, it SHOULD send a Notification message with PW status "Pseudowire in Loopback Mode". Otherwise, it SHOULD send a Notification message with the LDP Status code set to "Enter Loopback Failure" , and the Status bit "Pseudowire in Loopback Mode" MUST be cleared. When the Mapping message arrives at the targeted S-PE, the S-PE SHOULD try to put the PW in loopback mode. If the S-PE puts the PW into loopback mode successfully, it SHOULD send a Notification message with PW status set to "Pseudowire in Loopback Mode". An SP-PE TLV identifying the S-PE in loopback mode SHOULD also be carried in the Notification message. If the S-PE fails to put the PW into loopback mode, it SHOULD send a Notification message with the LDP Status code set to "Enter Loopback Failure" , and the Status bit "Pseudowire in Loopback Mode" MUST be cleared. An SP-PE TLV SHOULD also be carried in the Notification message. When the PE/T-PE wants to take the remote PE/T-PE out of the loopback mode, it MUST send a Mapping message with the Lock (K) bit set and Loopback (B) bit cleared. When the T-PE wants to take a particular S-PE out of loopback mode, the message SHOULD also carry the SP-PE TLV which identifies the target S-PE. If the PW is taken out of loopback mode successfully, the receiving PE/T-PE/S-PE SHOULD send a Notification message with PW status bit "Pseudowire in Loopback Mode" cleared. Otherwise, it SHOULD send a Notification message with the LDP Status code set to "Exit Loopback Failure" , and the Status bit "Pseudowire in Loopback Mode" MUST still be set. For the S-PE case, An SP-PE TLV identifying the S-PE SHOULD also be carried in the Notification message. Dong, et al. Expires September 2, 2012 [Page 5] Internet-Draft LDP Extensions for PW LI&LB March 2012 4. IANA Considerations Two bits ("Lock" (K) and "Loopback" (B)) as defined in section 2.1 need to be allocated in the MPLS-TP PW OAM Administration TLV. Two new PW Status bits as defined in section 2.2 need to be allocated in the "Pseudowire Status Codes" Registry. Four new LDP status codes need be assigned by the IANA in the LDP "STATUS CODE NAME SPACE": Range/Value E Description TBA 0 Lock Failure TBA 0 Unlock Failure TBA 0 Enter Loopback Failure TBA 0 Exit Loopback Failure 5. Security Considerations TBD 6. Acknowledgements TBD 7. References 7.1. Normative References [I-D.ietf-pwe3-oam-config] Zhang, F., Wu, B., and E. Bellagamba, "Label Distribution Protocol Extensions for Proactive Operations, Administration and Maintenance Configuration of Dynamic MPLS Transport Profile PseudoWire", draft-ietf-pwe3-oam-config-00 (work in progress), September 2011. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3985] Bryant, S. and P. Pate, "Pseudo Wire Emulation Edge-to- Edge (PWE3) Architecture", RFC 3985, March 2005. [RFC4447] Martini, L., Rosen, E., El-Aawar, N., Smith, T., and G. Heron, "Pseudowire Setup and Maintenance Using the Label Dong, et al. Expires September 2, 2012 [Page 6] Internet-Draft LDP Extensions for PW LI&LB March 2012 Distribution Protocol (LDP)", RFC 4447, April 2006. [RFC5659] Bocci, M. and S. Bryant, "An Architecture for Multi- Segment Pseudowire Emulation Edge-to-Edge", RFC 5659, October 2009. [RFC5860] Vigoureux, M., Ward, D., and M. Betts, "Requirements for Operations, Administration, and Maintenance (OAM) in MPLS Transport Networks", RFC 5860, May 2010. [RFC6073] Martini, L., Metz, C., Nadeau, T., Bocci, M., and M. Aissaoui, "Segmented Pseudowire", RFC 6073, January 2011. [RFC6371] Busi, I. and D. Allan, "Operations, Administration, and Maintenance Framework for MPLS-Based Transport Networks", RFC 6371, September 2011. 7.2. Informative References [RFC5586] Bocci, M., Vigoureux, M., and S. Bryant, "MPLS Generic Associated Channel", RFC 5586, June 2009. [RFC6435] Boutros, S., Sivabalan, S., Aggarwal, R., Vigoureux, M., and X. Dai, "MPLS Transport Profile Lock Instruct and Loopback Functions", RFC 6435, November 2011. Authors' Addresses Jie Dong Huawei Technologies Huawei Building, No.156 Beiqing Rd Beijing 100095 China Email: jie.dong@huawei.com Mach Chen Huawei Technologies Huawei Building, No.156 Beiqing Rd Beijing 100095 China Email: mach.chen@huawei.com Dong, et al. Expires September 2, 2012 [Page 7] Internet-Draft LDP Extensions for PW LI&LB March 2012 Greg Mirsky Ericsson Email: gregory.mirsky@ericsson.com Dong, et al. Expires September 2, 2012 [Page 8]