The IESG has approved the Internet-Draft 'Fault Tolerance for the Label
Distribution Protocol (LDP)' <draft-ietf-mpls-ldp-ft-06.txt> as a
Proposed Standard. This document is the product of the Multiprotocol
Label Switching Working Group. The IESG contact persons are Scott
Bradner and Bert Wijnen.
Technical Summary
Multiprotocol Label Switching (MPLS) systems will be used in core
networks where system downtime must be kept to an absolute minimum. Many
MPLS Label Switching Routers (LSRs) may, therefore, exploit Fault
Tolerant (FT) hardware or software to provide high availability of the
core networks.
The details of how FT is achieved for the various components of an FT
LSR, including Label Distribution Protocol (LDP), the switching hardware
and TCP, are implementation specific. This document identifies issues in
the LDP specification in RFC 3036 "LDP Specification" that make it
difficult to implement an FT LSR using the current LDP protocols, and
defines enhancements to the LDP specification to ease such FT LSR
implementations.
The issues and extensions described here are equally applicable to RFC
3212, "Constraint-Based LSP Setup Using LDP".
Working Group Summary
The mpls working group supported publication of this document.
Protocol Quality
This document was reviewed for the IESG by Scott Bradner.
RFC-Editor:
This IESG Note goes at the start of the document:
IESG Note: This specification includes procedures for
failure detection and failover for a TCP connection
carrying MPLS LDP control traffic. It is limited to that
application, and does not provide a general approach for
using TCP connections with applications requiring fault
tolerance. The specification lacks guidance for timer and
retry value choices. The specification should not serve
as a model for TCP fault tolerance design for any future
document, and any user is advised to test any configuration
based on this specification very carefully for problems
such as premature failovers.
