Internet DRAFT - draft-nadeau-pwe3-vccv2
draft-nadeau-pwe3-vccv2
PWE3 T. Nadeau
Internet-Draft Juniper Networks
Intended status: Standards Track C. Pignataro
Expires: January 5, 2013 Cisco Systems, Inc.
YJ. Stein
RAD Data Communications
July 4, 2012
Virtual Circuit Connectivity Verification version 2 (VCCV2)
draft-nadeau-pwe3-vccv2-00.txt
Abstract
This document describes VCCV2, a new version of Virtual Circuit
Connectivity Verification (VCCV), the pseudowire OAM mechanism. This
new version is backwards compatible with VCCV for MPLS PWs for modes
that the versions share, although the Router Alert (RA) CV type is
not supported by VCCV2. Furthermore, this document collects the
complete description of VCCV2 into a single specification.
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
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Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 5, 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
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publication of this document. Please review these documents
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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. Overview of the PW OAM Channel . . . . . . . . . . . . . . . . 3
3. Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. The Protocol and its Options . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
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1. Introduction
Virtual Circuit Connectivity Verification (VCCV), the pseudowire OAM
mechanism is described in [RFC5085], [RFC5885], and
[I-D.ietf-pwe3-vccv-for-gal]. This mechanism has been widely
implemented and deployed, but it has been reported
[I-D.ietf-pwe3-vccv-impl-survey-results] that the large number of
VCCV options has led to interoperability issues.
[RFC5085] together with [I-D.ietf-pwe3-vccv-for-gal] define four
Control Channel (CC) types for MPLS PWs:
Type 1 using the control word (CW),
Type 2 using the Router Alert label (label=1) above the PW label,
Type 3 using TTL expiry,
Type 4 using G-ACh Label (label=13) [RFC5586] below the PW label.
In order to simplify implementations and operations, we herein
obsolete Type 2, and provide guidance as to when to use the remaining
three types.
[RFC5085] together with [RFC5885] define four Connectivity
Verification (CV) types for MPLS PWs:
ICMP ping,
LSP ping,
BFD with UDP/IP encapsulation,
raw BFD (without IP encapsulation),
and BFD has several options of its own (see [RFC5880]). The
description of what and how to implement these is spread over several
documents, and we herein attempt to summarize the entire
functionality set in one place.
This document only describes OAM for PWs over MPLS. Functionality
for L2TPv2-based PWs remains as presently specified.
The present version of this document is a skeleton only, intended to
initiate discussion. Once the principles are agreed upon, the
authors will flesh out the rest.
2. Overview of the PW OAM Channel
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 [RFC2119].
VCCV and VCCV2 are fault OAM mechanisms to verify liveliness and to
further diagnose the pseudowire forwarding path. This section will
provide an overview of the requirements and architecture of PW OAM.
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3. Abbreviations
AC Attachment Circuit [RFC3985]
CC Control Channel (used as CC Type)
CE Customer Edge
CV Connectivity Verification (used as CV Type)
CW Control Word [RFC3985]
GACh Generic Associated Channel [RFC5586]
GAL GACh Channel Label [RFC5586]
MPLS-TP MPLS-Transport Profile
OAM Operations, Administration and Maintenance
PE Provider Edge
PSN Packet Switched Network [RFC3985]
PW Pseudowire [RFC3985]
PW-ACH PW Associated Channel Header [RFC4385]
VCCV Virtual Circuit Connectivity Verification
4. The Protocol and its Options
This section will detail all the CC and CV options, the signaling
needed to choose each of them, the bit-masks and codings. The
description will be concise, yet readable.
In particular, CC Type 2 is obsoleted. Subsections will discuss
Types 1, 3, and 4.
In addition, the text will provide guidance for selection of CC
types, as follows: When the PW employs a CW then CC Type 1 SHOULD be
used. TDM PWs always use the CW, and thus SHOULD always use Type 1.
Legacy (ATM, port mode frame relay, and HDLC PWs) without CWs SHOULD
use Type 3. [RFC5994] states that Ethernet PWs over MPLS-TP MUST use
the CW, and thus they SHOULD use Type 1, but MAY use Type 4.
Discussion is needed as to whether all CV types are required.
Subsections will detail the use of the different CV types.
5. Security Considerations
Are there significant threats on PWs based on VCCV?
6. IANA Considerations
It is not clear what needs to be put here. Will CC Type 2 be
removed?
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7. References
7.1. Normative References
[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.
[RFC4385] Bryant, S., Swallow, G., Martini, L., and D. McPherson,
"Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for
Use over an MPLS PSN", RFC 4385, February 2006.
[RFC5085] Nadeau, T. and C. Pignataro, "Pseudowire Virtual Circuit
Connectivity Verification (VCCV): A Control Channel for
Pseudowires", RFC 5085, December 2007.
[RFC5586] Bocci, M., Vigoureux, M., and S. Bryant, "MPLS Generic
Associated Channel", RFC 5586, June 2009.
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, June 2010.
[RFC5885] Nadeau, T. and C. Pignataro, "Bidirectional Forwarding
Detection (BFD) for the Pseudowire Virtual Circuit
Connectivity Verification (VCCV)", RFC 5885, June 2010.
[RFC5994] Bryant, S., Morrow, M., Swallow, G., Cherukuri, R.,
Nadeau, T., Harrison, N., and B. Niven-Jenkins,
"Application of Ethernet Pseudowires to MPLS Transport
Networks", RFC 5994, October 2010.
[I-D.ietf-pwe3-vccv-for-gal]
Nadeau, T. and L. Martini, "A Unified Control Channel for
Pseudowires", draft-ietf-pwe3-vccv-for-gal-01 (work in
progress), May 2012.
7.2. Informative References
[I-D.ietf-pwe3-vccv-impl-survey-results]
Regno, N., "The Pseudowire (PW) & Virtual Circuit
Connectivity Verification (VCCV) Implementation Survey
Results", draft-ietf-pwe3-vccv-impl-survey-results-00
(work in progress), April 2012.
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Authors' Addresses
Thomas D. Nadeau
Juniper Networks
Email: tnadeau@juniper.net
Carlos Pignataro
Cisco Systems, Inc.
7200-12 Kit Creek Road
PO Box 14987
Research Triangle Park, NC 27709
USA
Email: cpignata@cisco.com
Yaakov (Jonathan) Stein
RAD Data Communications
24 Raoul Wallenberg St., Bldg C
Tel Aviv 69719
ISRAEL
Email: yaakov_s@rad.com
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