[c-nsp] Redundant default route, without round-robin routing

[Vincent De Keyzer]

Hello list,

 

I would like your ideas to complete my design.

 

This is an ISP network. All 10 routers in the city are interconnected on a
/27 subnet, over which everybody has a full OSPF adjacency with the DR and
the BDR.

 

Two of those routers are BGP-connected to the upstream providers (one each).
The other routers are access routers, and cannot hold a full BGP table; they
hence need a default route.

 

I was thinking of having both BGP routers advertising a default route in
OSPF; but in this case, in order to limit packet out-of-sequence problems, I
want to make sure that every IP flow uses the same default gateway.

 

Is there a way to ensure that? Or should I proceed differently at routing
level (how) ?

 

Thanks in advance,

 

Vincent