[j-nsp] BGP multipath question

[tim tiriche]

Hello,

I would like to know when does Multipath kick in the BGP path selection process.

lets say, i have 2 routers, rtrA and rtrB connected with two physical links.

First,

For example, if i were to configure rtrA with 'multipath' and if rtrB
would advertise a prefix on one session
with shorter as_path.  would rtrA load balance or would that break it?


Second,

I heard the following, is this true, if i have EIbgp multipath
configured. (mpls vpn environment)

if rtrA is Cisco and receives route 192.168/24 with AS_PATH 100 200
and AS_PATH 100 300.
Cisco routers would not consider them to be the same even though the
length is the same but the ASN's are different
and move on to the next process in BGP decision process and break
eibgp multipath.

However, if rtrA were a juniper, the AS_path length would be
considered the same and rtrA would load balance.
If so, are there any knobs to change this?


Last, whats the equivalent of maximum-paths eibgp in juniper?

Any pointers or documentation that explains more on this would be
appreciated. (rfc's, whitepapers, search terms to use, books, etc)



Sincerely,
-- Tim