Re: BGP announce/withdrawal history.

[Joe Abley <jabley () ca afilias info>]

On 24-May-2007, at 03:42, Forrest W. Christian wrote:

> Earlier today I had an issue where a circuit to one of my two BGP  
> connected upstreams went away for an hour or so.
> During this period, I expected BGP to act as expected and migrate  
> the traffic to the second circuit with a second provider.  This did  
> not occur.

When this has happened to me before, I have been suspicious about  
whether the upstream to whom the circuit broke was routing my nets  
down the dead circuit with static routes that for whatever reason  
(layer-2 obfuscation, etc) didn't go away when the link went down.

This hasn't always been the answer, but sometimes it has; in several  
cases poking about within RIS (or interactively through a route-views  
router while the circuit was down) revealed that upstream in question  
was originating routes on my behalf while the circuit was down.


Joe