[j-nsp] Announcing aggregate route via BGP to peers

[Chuck Anderson]

On Tue, Mar 03, 2009 at 08:44:30AM -0500, John Center wrote:
> What's happening is by specifying the aggregate route this way, it is  
> appears to be announcing the aggregate of all the ebgp routes it sees:

I'm unclear on what you mean here.  Do you mean that it is advertising 
153.104.0.0/16, or that it is advertising all the contributing members 
of that aggregate?

> admin at KC-JNM120-1a> show route protocol aggregate
>
> inet.0: 277655 destinations, 559869 routes (277481 active, 0 holddown,  
> 337 hidden)
> @ = Routing Use Only, # = Forwarding Use Only
> + = Active Route, - = Last Active, * = Both
>
> 153.104.0.0/16     *[Aggregate/130] 18w6d 00:22:28
>                       Discard

That looks correct.  If you add "extensive" you can see what the 
contributing routes are.

> But, the ebgp routes were still being announced, with a next hop of  
> SELF.  I'm at a loss on the best way to approach this problem.  I only  
> want to announce the locally-defined aggregate, not all of the others.

Do you want to control which routes contribute to the aggregate?  You 
can define a policy for that.  For example, to only allow static, 
direct, and OSPF routes to contribute to (make active) the aggregate:

routing-options {
   ...
    aggregate {
        route 153.104.0.0/16 discard;
	policy AGG-CONTRIB;
    }
   ...
}

policy-statement AGG-CONTRIB {
    term MY-ROUTES {
        from protocol [ static direct ospf ];
	then accept;
    }
    term ELSE-REJECT {
        then reject;
    }
}