[j-nsp] MX480 - 10.4R4.5 BGP

[Brandon Ross]

On Wed, 16 Jan 2013, Keith wrote:

> Peer #1 - all 4 networks are prepended with our AS 5 times:

Okay so far...

> This way I have two networks coming in on one gig link and the other two
> networks are coming in over the other gig link.

No, you don't.  You have all 4 networks coming in on all 4 links.

> There should be no traffic incoming in on Peer #1 from the internet. But 
> there is.

Not quite.  You have advertised a route to another AS.  Each AS will use 
it's own criteria to decide how to route traffic.  For example, most 
service providers will prefer to send traffic to their customers' direct 
connections instead of sending that traffic to an intermediate AS.  That 
preference is usually implemented using localpref which is a decision made 
by routers before AS path length, just like you are doing to choose how to 
send traffic out of your network.

The only way to ensure that NO traffic comes in on that link is to 
advertise NO routes at all.

You can, however, influence traffic in a stronger way by advertising more 
specific routes (since more specific routes are always preferred) on links 
that you want to carry traffic.

-- 
Brandon Ross                                      Yahoo & AIM:  BrandonNRoss
+1-404-635-6667                                                ICQ:  2269442
Schedule a meeting:  https://doodle.com/bross            Skype:  brandonross