selective auto-aggregation

Thu Apr 17 20:48:47 UTC 2003

I do it. Reasons are to control inbound traffic better, some routes are 
annnounced to all upstreams, some are to some specific ones, some have 
different communities tagged to them, etc. I have one block which is /19 
which I do not announce and only announce multiple /23, /24 out of. It 
works just fine - I'v not seen one place which does not route there... 

> I was curious how much of the de-aggregation was due to multi-homed 
> companies requiring the longer prefixes. Are there companies that 
> actually announce their smaller routes despite controlling the shorter 
> prefix? What would be the benefit of doing so?
> 
> -Jack
> 