Subject: [Isis-wg] I-D ACTION:draft-ietf-isis-restart-04.txt

From: [email-masked]
Date: Wed, 23 Jul 2003 15:15:27 -0400

A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the IS-IS for IP Internets Working Group of the IETF.

	Title		: Restart signaling for IS-IS
	Author(s)	: M. Shand, L. Ginsberg
	Filename	: draft-ietf-isis-restart-04.txt
	Pages		: 17
	Date		: 2003-7-23
	
The IS-IS routing protocol (RFC 1195 [2], ISO/IEC 10589 [3]) is a 
link state intra-domain routing protocol. Normally, when an IS-IS 
router is restarted, temporary disruption of routing occurs due to 
events in both the restarting router and the neighbors of the 
restarting router. 
The router which has been restarted computes its own routes before 
achieving database synchronization with its neighbors. The results 
of this computation are likely to be non-convergent with the routes 
computed by other routers in the area/domain. 
Neighbors of the restarting router detect the restart event and 
cycle their adjacencies with the restarting router through the down 
state. The cycling of the adjacency state causes the neighbors to 
regenerate their LSPs describing the adjacency concerned. This in 
turn causes temporary disruption of routes passing through the 
restarting router. 
In certain scenarios the temporary disruption of the routes is 
highly undesirable. This draft describes mechanisms to avoid or 
minimize the disruption due to both of these causes.

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-ietf-isis-restart-04.txt

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From: Les Ginsberg <[email-masked]>
Date: Wed, 23 Jul 2003 13:00:32 -0700

Folks -

The version of the draft which is posted at the URL below is NOT the latest 
text. I am working with IETF to straighten this out. In the interim I 
suggest you simply ignore this announcement.

My apologies for any confusion.

    Les

At 03:15 PM 7/23/2003 -0400, [email-masked] wrote:
>Content-Type: text/plain
>Content-ID:     <[email-masked]>

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From: Les Ginsberg <[email-masked]>
Date: Mon, 28 Jul 2003 20:49:30 -0700

Folks -

The correct text for V4 of the draft is now posted. Thank you for your 
patience.
BTW, if in doubt, the correct version can be identified by the dates - 
which are "July 2003 - January 2004".

Here is a summary of the significant changes from V3 to V4.

    Les

V4 of the restart draft, in addition to numerous editorial improvements, 
includes the following significant changes:

1)In earlier versions acceptance of the holdtime in an IIH/RR by the helper 
routers was optional. A number of testing situations convinced us that this 
policy was flawed. It has been replaced by a policy which mandates 
acceptance of the holdtime in an IIH/RR with some provisions to prevent a 
router which is constantly restarting from maintaining an adjacency beyond 
all reason.

2)The addition of a "Restarting Neighbor System ID" to the restart TLV to 
identify the neighbor to whom the RA bit refers. This is necessary in order 
to disambiguate RAs in the case that two or more neighbors on a LAN restart 
at approximately the same time.

3)Noting that timer T3 is not to be used in case of a starting router since 
it serves no purpose in this case.

4)A loophole in reliability of the LSP DB resync process that could occur 
when there is a non-restart capable neighbor on a Pt-Pt circuit is closed.

5)State tables have been added