North American Network Operators Group

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Re: seeing the trees in the forest of confusion

  • From: Alex.Bligh
  • Date: Sat Apr 26 11:23:37 1997

>   I suppose it is more fun to criticize policy and NSPs, but it
>   may well be a hole in the BGP protocol, or more likely
>   implementations in vendor's code [or user's implementation
>   of twiddleable holddown timers].

My (possibly misinformed) understanding was that certain NSPs running
Cisco backbones had holddown timers configured to delay withdrawls. Even
after 7007 was disconnected, there were 7007 routes still being advertised
well over an hour later. I do not believe these NSPs are going to have
timers configured for >1hr.

We've seen a problem before where a transit provider (Cisco based) was
causing us problems, and we decided to turn them off. They were still
advertising our routes an hour later. (Provider unconnected with any
in this case). Pulling the session back up and clearing it did not
help things.

I'd therefore suggest that your analysis is correct. >80% of the
downtime is due either to a protocol bug or a s/w bug somewhere, not
NOC failure.

Alex Bligh
Xara Networks

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