Network Working Group N. McGill
Request for Comments: 5641 C. Pignataro
Updates: 3931, 4349, 4454, 4591, 4719 Cisco Systems
Category: Standards Track August 2009
Layer 2 Tunneling Protocol Version 3 (L2TPv3)
Extended Circuit Status Values
Abstract
This document defines additional Layer 2 Tunneling Protocol Version 3
(L2TPv3) bit values to be used within the "Circuit Status" Attribute
Value Pair (AVP) to communicate finer-grained error states for
Attachment Circuits (ACs) and pseudowires (PWs). It also generalizes
the Active bit and deprecates the use of the New bit in the Circuit
Status AVP, updating RFC 3931, RFC 4349, RFC 4454, RFC 4591, and RFC
4719.
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
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McGill & Pignataro Standards Track [Page 1]
RFC 5641 L2TPv3 Extended Circuit Status Values August 2009
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Specification of Requirements . . . . . . . . . . . . . . 2
1.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 3
2. L2TPv3 Extended Circuit Status Values . . . . . . . . . . . . 3
3. Circuit Status Usage and Clarifications . . . . . . . . . . . 7
4. Updates to Existing RFCs . . . . . . . . . . . . . . . . . . . 8
5. Security Considerations . . . . . . . . . . . . . . . . . . . 9
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9
8.1. Normative References . . . . . . . . . . . . . . . . . . . 9
8.2. Informative References . . . . . . . . . . . . . . . . . . 10
1. Introduction
Currently, the L2TPv3 Circuit Status AVP [RFC3931] is able to convey
the UP/DOWN status of an access circuit. However, a finer
granularity is often useful to determine the direction of the fault,
as has been added for MPLS-based pseudowires and is used in the
pseudowire control protocol using the Label Distribution Protocol
(LDP); see Section 3.5 of [RFC4446] and Section 5.4.2 of [RFC4447].
Additionally, it is useful (in session-level redundancy scenarios) to
be able to indicate if a pseudowire is in a standby state, where it
is fully established by signaling and allows Operations,
Administration, and Maintenance, but is not switching data. Again,
such functionality is available for MPLS-based pseudowires using LDP,
see [PREF-FWD].
This document provides extended circuit status bit values for L2TPv3
and adds them in a manner such that it is backwards compatible with
the current Circuit Status AVP. These new bits are applicable to all
pseudowire types that use the Circuit Status AVP.
1.1. Specification of Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
datatracker.ietf.org