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Graceful Shutdown in MPLS Traffic Engineering Networks

draft-ali-ccamp-mpls-graceful-shutdown-03.txt

Zafar Ali (zali@cisco.com)Jean Philippe Vasseur (jpv@cisco.com)

Anca Zamfir (ancaz@cisco.com)

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History of the Draft

• It was first presented at IETF 60 in August 2004.

• There is a general agreement on the requirements and the Signaling Solution. • We need to close on a minor detail in the Routing

Solution (discussion focus for today).

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Motivation for using the link-attribute sub-TLV

• The draft proposes to use link-attribute sub-TLV with “local maintenance required” bit, as defined in http://www.ietf.org/internet-drafts/draft-ietf-isis-link-attr-01.txt.

• Draft discusses the possibility of using (MAX-METRIC, Zero Bandwidth) based solution but also points out some issues associated with this solution-

A link may end-up with max metric for multiple reasons and without the link attribute there is no way a node can tell what the reason is, e.g. a restarting node advertises the max matrices [RFC4203 , RFC4205].

A resource under graceful shutdown can be used as a last resort resource.

• The ID states the following backward compatibility note-

"to deal with nodes not compliant with this document (i.e., does not implement link attribute sub-TLV based solution), the node initiating graceful shutdown MAY originate the TE LSA/LSP containing Link TLV with 0 unreserved bandwidth, Traffic Engineering metric set to 0xffffffff, and if the Link is non-PSC then also with 0 as Max LSP Bandwidth.“.

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Next Steps

• There is a general agreement on the requirements and signaling solution.

• We would like to close on routing solution quickly.

• The work is within the Scope of CCAMP.

• We would like to request WG to accept this ID as a WG document.