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Re: Adopting draft-francois-ordered-fib-00.txt as a WG document

Subject: Re: Adopting draft-francois-ordered-fib-00.txt as a WG document
From: Stewart Bryant
Date: Tue, 22 Nov 2005 08:02:32 +0000
Joel M. Halpern wrote:

I am really uncomfortable with changing the general convergence behavior of the routing protocols to handle the case when the human knows he will shut things down. If this were only triggered by a special advertisement that indicated orderly shutdown, that might be less bothersome. Particularly, it seems strange to be talking about slowing convergence when we are repeatedly being asked to speed up convergence.
Joel M. Halpern

Please can we be clear that PLSN (which is of course a WG draft)
has very similar properties -

1) It slows convergence to some extent (with as far as I can see
- no mechanism to use signalling to accelerate)

2) Needs to be applied to all routers in the network

It therefore changes the convergence properties of the whole
network, but it does not provide complete protection against
all loops.

If we have doubts as to whether we wish to change the convergence
process,  maybe we should put the PLSN draft on hold?

Convergence dynamics can be safely modified when we are sure that
that all traffic will continue to be safely delivered during the
process. This is true IFF the old path is still functional or
when ALL traffic that was previously using  it is protected.

- Stewart

At 04:17 PM 11/21/2005, Olivier Bonaventure wrote:

Dear All,

We would like to propose to consider draft-francois-ordered-fib-00.txt
as a working group document. This draft was presented in Paris and no
objections were raised. It proposes techniques to order the FIB updates
in an IP network using a link state routing protocol to avoid transient
forwarding loops. We believe that this draft is important for the fast
reroute work done within this WG, but also as a standalone document.
Measurements performed in IP networks show that planned topology changes
are very common. For example, [1] reports that in the Sprint network,
20% of the topology changes are due to maintenance operations. We
discussed this issue with several ISPs that confirmed that correctly
handling the non-urgent topology changes was an important problem to be

You can find the current version of the draft on the IETF web site

[1] Athina Markopoulou and Gianluca Iannaccone and Supratik
Bhattacharyya and Chen-Nee Chuah and Christophe Diot (2004).
Characterization of Failures in an IP Backbone.
In: IEEE Infocom. Hong Kong. March 2004.

Best regards,

Olivier Bonaventure

CSE Dept. UCL, Belgium - http://www.info.ucl.ac.be/people/OBO/

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