BGP TTL

[Danny McPherson]

'course, in this world of closest-exit inter-domain routing,
one can with certainty assign new community values on ingress 
and get a reasonable idea of geographic distribution of data 
sources on the peers network.  Of course, this is assuming 
MED brokenness or other policy isn't skewing "good ole 
closest-exit" path selection.

Not only would conflicting assignments be an issue, but I'm
guessing that with the number of available paths impacting 
Adj-RIB-In size today, a default "additive" community policy 
would result in a notable impact in memory utilization.  

The work we're seeing from lots of folks is attempting to scope 
advertisement of "distant" policy for this and other reasons, 
not multiply it.

-danny


> This is very true of course but I can see value in receiving communities
> from peers too. For example, one might want to use a tool that can
> provide you with the amount of traffic destined for a specific community
> that represents a geography in your peer's network. As tools develop in
> this area, which they are, I can see communities being useful to get
> other traffic or performance-related data.