Network Working Group G. Mirsky Internet-Draft Ericsson Intended status: Standards Track July 13, 2012 Expires: January 14, 2013 VCCV MPLS-TP Connectivity Verification (CV) Capability Advertisement draft-mirsky-mpls-tp-cv-adv-01 Abstract This document specifies how use of proactive Connectivity Verification, Continuity Check, and Remote Defect Indication for the MPLS Transport Profile [RFC6428] affects operation and management function election for PW VCCV [RFC5085], [RFC5885]. 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 January 14, 2013. 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 (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. Mirsky Expires January 14, 2013 [Page 1] Internet-Draft VCCV MPLS-TP CV July 2012 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Conventions used in this document . . . . . . . . . . . . . 3 1.1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . 3 1.1.2. Requirements Language . . . . . . . . . . . . . . . . . 3 2. MPLS-TP CC-CV on Pseudowires . . . . . . . . . . . . . . . . . 3 2.1. VCCV Extended CV Advertisement sub-TLV . . . . . . . . . . 4 2.2. MPLS-TP CC-CV Types . . . . . . . . . . . . . . . . . . . . 4 2.3. MPLS-TP CC-CV Type Operation . . . . . . . . . . . . . . . 5 2.4. CV Type Selection . . . . . . . . . . . . . . . . . . . . . 5 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 3.1. VCCV Extended CV Types . . . . . . . . . . . . . . . . . . 6 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 6.1. Normative References . . . . . . . . . . . . . . . . . . . 7 6.2. Informative References . . . . . . . . . . . . . . . . . . 8 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 8 Mirsky Expires January 14, 2013 [Page 2] Internet-Draft VCCV MPLS-TP CV July 2012 1. Introduction Proactive Connectivity Verification (CV), Continuity Check (CC), and Remote Defect Indication (RDI) for the MPLS Transport Profile [RFC6428] is applicable to all constructs of the MPLS-TP, including pseudowires (PWs). If Control Plane is used to operate and manage PW then procedure defined in [RFC5085] and [RFC5885] should be used to select proper type of Control Channel and corresponding type of Connectivity Verification. This document specifies how signaling and selection process modified to ensure backward compatibility and allow use of proactive CV-CC-RDI over MPLS-TP PWs. 1.1. Conventions used in this document 1.1.1. Terminology BFD: Bidirectional Forwarding Detection CC: Continuity Check CV: Connectivity Verification PE: Provider Edge VCCV: Virtual Circuit Connectivity Verification VCCV CC: VCCV Control Channel 1.1.2. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 2. MPLS-TP CC-CV on Pseudowires PW VCCV can support several CV Types. Ability to support arbitrary combination of CV modes advertised in CV Types field of VCCV Interface Parameter sub-TLV [RFC4446], [RFC4447]. Currently six types of CV been defined for PW VCCV out of eight bit long field. This document introduces four new CV types and to accommodate them a new VCCV Extended CV parameter for PW Interface Parameters Sub-TLV is defined. Mirsky Expires January 14, 2013 [Page 3] Internet-Draft VCCV MPLS-TP CV July 2012 2.1. VCCV Extended CV Advertisement sub-TLV The format of VCCV Extended CV Advertisement is a TLV where: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 0x19 | Length | CV Type | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: VCCV Extended CV parameter format Length - the length of the sub-TLV, including type and the Length field itself. Minimum length is 4. It it isrecommended that extensions to the sub-TLV be done in 4 bytes increments with Reserved field being set to zero on transmit and ignored on receipt. Reserved field must be set to zeroes on transmit and ignored on receive. CV Type field is a bitmask that lists types of CV monitoring that a PE is capable to support. VCCV Extended CV parameter sub-TLV must appear in combination with VCCV parameter sub-TLV. If VCCV parameter sub-TLV is missing then VCCV Extended CV parameter sub-TLV should be ignored. 2.2. MPLS-TP CC-CV Types The [RFC6428] defines coordinated and independent modes of monitoring point-to-point bi-directional connection that can be applied to monitoring PWs. At the same time [RFC6310] defines how BFD-based OAM can map and be mapped to status of an Attachment Circuit. Thus there could be four MPLS-TP CV types as combination of modes and functionality: +---------------+-------------------+-------------------------------+ | Modes | Fault Detection | Fault Detection and Status | | | Only | Signalling | +---------------+-------------------+-------------------------------+ | Independent | 0x01 | 0x02 | | Mode | | | | Coordinated | 0x04 | 0x08 | | Mode | | | +---------------+-------------------+-------------------------------+ Table 1: Bitmask Values for MPLS-TP CV Types Mirsky Expires January 14, 2013 [Page 4] Internet-Draft VCCV MPLS-TP CV July 2012 2.3. MPLS-TP CC-CV Type Operation Connectivity verification according to [RFC6428] is part of MPLS-TP CC/CV operation that can be used with VCCV Control Channel Types 1 [RFC5085] or Type 4 [I-D.ietf-pwe3-vccv-for-gal]. If VCCV CC Type 1 or Type 4 selected, then PEs might select one of MPLS-TP CC-CV types as VCCV CV mechanism to be used for this PW. 2.4. CV Type Selection CV selection rules that have been defined in Section 7 of [RFC5085] and updated Section 4 of [RFC5885] are augmented in this document. If VCCV Control Channel Type 1 or Type 4 is chosen according to Section 7 [RFC5085] or Section 4 [I-D.ietf-pwe3-vccv-for-gal] and common set of proactive CV types advertized by both PEs includes MPLS-TP CC-CV types and some BFD CV types, then MPLS-TP CC-CV takes precedence over any type of BFD CV. If multiple MPLS-TP CV types advertised by both PEs, then following list sorted in descending priority order is used: 1. 0x08 - coordinated mode for PW Fault Detection and AC/PW Fault Status Signaling 2. 0x04 - coordinated mode for PW Fault Detection only 3. 0x02 - independent mode for PW Fault Detection and AC/PW Fault Status Signaling 4. 0x01 - independent mode for PW Fault Detection only 3. IANA Considerations The PW Interface Parameters Sub-TLV registry defined in [RFC4446]. IANA is requested to reserve a new PW Interface Parameters Sub-TLV type as follows: +-------------+--------+----------------------------+---------------+ | Parameter | Length | Description | Reference | | ID | | | | +-------------+--------+----------------------------+---------------+ | 0x19 | 4 | VCCV Extended CV Parameter | This document | +-------------+--------+----------------------------+---------------+ Table 2: New PW Interface Parameters Sub-TLV Mirsky Expires January 14, 2013 [Page 5] Internet-Draft VCCV MPLS-TP CV July 2012 Parameter ID Length Description Reference 0x19 4 VCCV Extended CV parameter This document 3.1. VCCV Extended CV Types IANA is requested to set up a registry of ?VCCV Extended CV Types?. These are 8 bitfield values. Extended CV Type values 0x01, 0x02, 0x04 and 0x08 are specified in Section 2.2 of this document. The remaining bitfield values (0x10 through 0x80) are to be assigned by IANA using the "IETF Consensus" policy defined in [RFC2434]. A VCCV Extended Control Verification Type description and a reference to an RFC approved by the IESG are required for any assignment from this registry. +--------------+----------------------------------------------------+ | Bit(Value) | Description | +--------------+----------------------------------------------------+ | Bit 0 (0x01) | Independent mode for PW Fault Detection only | | Bit 1 (0x02) | Independent mode for PW Fault Detection and AC/PW | | | Fault Status Signaling | | Bit 2 (0x04) | Coordinated mode for PW Fault Detection only | | Bit 3 (0x08) | Coordinated mode for PW Fault Detection and AC/PW | | | Fault Status Signaling | | Bit 4 (0x10) | Reserved | | Bit 5 (0x20) | Reserved | | Bit 6 (0x40) | Reserved | | Bit 7 (0x80) | Reserved | +--------------+----------------------------------------------------+ Table 3: MPLS Connectivity Verification (CV) Types 4. Security Considerations Routers that implement the additional CV Type defined herein are subject to the same security considerations as defined in [RFC5085], [RFC5880], [RFC5881], and [RFC6428]. This specification does not raise any additional security issues beyond these. 5. Acknowledgements The author gratefully acknowledges the thoughtful review, comments, and explanations provided by Dave Allan, and by Carlos Pignataro. 6. References Mirsky Expires January 14, 2013 [Page 6] Internet-Draft VCCV MPLS-TP CV July 2012 6.1. Normative References [I-D.ietf-pwe3-vccv-for-gal] Martini, L. and T. Nadeau, "A Unified Control Channel for Pseudowires", draft-ietf-pwe3-vccv-for-gal-00 (work in progress), January 2012. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4446] Martini, L., "IANA Allocations for Pseudowire Edge to Edge Emulation (PWE3)", BCP 116, RFC 4446, April 2006. [RFC4447] Martini, L., Rosen, E., El-Aawar, N., Smith, T., and G. Heron, "Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP)", RFC 4447, April 2006. [RFC5085] Nadeau, T. and C. Pignataro, "Pseudowire Virtual Circuit Connectivity Verification (VCCV): A Control Channel for Pseudowires", RFC 5085, December 2007. [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection (BFD)", RFC 5880, June 2010. [RFC5881] Katz, D. and D. Ward, "Bidirectional Forwarding Detection (BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881, June 2010. [RFC5882] Katz, D. and D. Ward, "Generic Application of Bidirectional Forwarding Detection (BFD)", RFC 5882, June 2010. [RFC5885] Nadeau, T. and C. Pignataro, "Bidirectional Forwarding Detection (BFD) for the Pseudowire Virtual Circuit Connectivity Verification (VCCV)", RFC 5885, June 2010. [RFC6310] Aissaoui, M., Busschbach, P., Martini, L., Morrow, M., Nadeau, T., and Y(J). Stein, "Pseudowire (PW) Operations, Administration, and Maintenance (OAM) Message Mapping", RFC 6310, July 2011. [RFC6428] Allan, D., Swallow Ed. , G., and J. Drake Ed. , "Proactive Connectivity Verification, Continuity Check, and Remote Defect Indication for the MPLS Transport Profile", RFC 6428, November 2011. Mirsky Expires January 14, 2013 [Page 7] Internet-Draft VCCV MPLS-TP CV July 2012 6.2. Informative References [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. Author's Address Greg Mirsky Ericsson Email: gregory.mirsky@ericsson.com Mirsky Expires January 14, 2013 [Page 8]