[c-nsp] bgp & static default route?

[Pete Templin]

matthew zeier wrote:

> Management is of the opinion that the best way to run this network is 
> with full BGP routes and static defaults out uplink interfaces 
> redistributed into OSPF.  The thinking process is that if a external 
> peer stops sending me all routes, I still need a way to get out.

Time out: thinking process is slightly flawed.  If an external peer 
stops sending you routes, your traffic leaves by another external peer 
if you are still receiving a route for that destination.  If both 
external peers stop sending you route(s), traffic to the affected 
destinations now leaves based on the default route.

> I content that if an external peer stops sending me full routes, why 
> should I send them traffic they don't think they know how to get to?  
> And if all routers are running bgp, I don't see how the static default 
> will ever help unless I lose all external bgp routes at which point 
> there's probably a bigger problem and I'm probably offline.

Failure modes aren't binary.  What if they stop sending you SOME routes? 
  Early in my multihome days, my providers (InterNAP) had a problem with 
their route tuning magic that caused some 55k routes to not be sent to 
BGP customers.  I had default routes out, so I was fine, but a 
single-homed BGP customer (who planned to multihome, and did so a few 
months later) didn't, so he lost a few more hairs.

> Any comments?  Is this how anyone else runs a network?

Yes.

pt