[c-nsp] BGP Multihomed Selective/Conditional Advertisement

[Nathan]

On Mon, Oct 27, 2008 at 11:56 PM,  <tkacprzynski at spencerstuart.com> wrote:
> So what would be the behavior if I set the community for Cogent to set
> the Local Preference to 50 in terms of transit traffic? Does that mean
> that Cogent's originated traffic would use ATT but Cogent's peers (with
> a shorter AS path through Cogent) would still traverse Cogent even
> though the lower local preference is there?

Check out "BGP Best Path Selection" on google :-)

I think it would go like this : if Cogent has a direct connection to
ATT, then traffic from Cogent and everywhere closer to Cogent will go
from Cogent to ATT and then to you. If Cogent does not have a direct
connection to ATT (OK so that is unlikely), then traffic will leave
Cogent on a path towards ATT . . . and the intermediary might just
send it back to Cogent . . .

--
HTH,
Nathan