The Cidr Report

Joe Abley jabley at isc.org
Fri Nov 14 19:52:08 UTC 2003


On 14 Nov 2003, at 14:41, McBurnett, Jim wrote:

> just how bad is the auto-summarization at the upstream for the route 
> propagation
> via BGP in the large routers anyway?

What auto-summarisation?

If you're talking about the cisco "auto-summary" command, then the 
answer is "so bad that it's universally disabled" (but then 
"auto-summary" is concerned with aggregation on pre-CIDR, classful 
boundaries which I don't think is what you were talking about).

Absent a precise understanding of all the routing policies concerned, 
proxy aggregation is dangerous and is hence generally not done.


Joe




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