[c-nsp] Default route pointed to an interface

[Justin Shore]

Seth Mattinen wrote:
> Justin Shore wrote:
>>
>> I have a pair of border routers, 1 with 2 upstream connection and the 
>> other with a single connection.  I'm pulling down full tables from each 
>> provider and have iBGP between the border routers and the core routers. 
>>   Each border router has a static default pointed to the outgoing 
>> interface for the local upstream connections (2 on one router and 1 on 
>> the other).  As expected the router with 2 default routes flops back and 
>> forth between the 2 interfaces every second or two.
> 
> If you have a full mesh and full tables from your upstreams, what do you 
> need default routes for? I only ask because I have a similar setup and I 
> have no need for a default route in anything that speaks BGP.

The mesh only covers the 2 border routers and 2 core routers; the core 
routers in POP1 are meshed with the core routers in POP2; the core 
routers in POP2 are meshed with the border router in POP2.  There are 
many more devices downstream of the core routers that need the default 
route.  We tried originating the default on the cores but this caused 
the border routers to learn their default route from the core routers 
(rather counter-productive).  The only working method we could find is 
originating the default on the borders.

Thanks
  Justin