[Re: selective auto-aggregation]

Fri Apr 18 15:24:21 UTC 2003

Joshua Smith wrote:
> i have been told that it is that way for 'backup' purposes (they 
> announce one or two /2[456]s to me with about 15 as prepends, and 
> announce their entire /20, plus all of their longer prefixes, to another
> provider)
> they also told me that it will not be changed...apparently, as routers
> get more powerful and memory gets 'cheaper', they feel that it is not
> their responsibility to help maintain global routing table sizes
> 

That's just beyond me. Since local preference is chosen before AS hop 
count, providers that are setup right allow for easily crafting your 
routing. I run an AS prepend out Sprint with default LP, which allows 
any packet that makes it to their network to come strait to me, but 
anyone that is multi-homed or exterior will probably go out another way. 
I work with communities to make routing symetrical as possible (not 
perfect, but close). Then I shoot out my aggregates via Qwest untouched 
and it's smooth sailing with a backup.

Then again, when dealing with various providers over the years, I've 
gotten some funny looks when I start talking communities and the need 
for symetrical routing.

-Jack