BGP/Multihoming

Fri Nov 7 15:56:41 UTC 1997

> The diagram below describes our current set-up:
> 
> * We have two default routes via BGP with MCI (L1 and L2) for outgoing
>   traffic.
> * The two MCI links are configured to load share incoming traffic thru the
>   use of MEDs.
> 
> Questions:

Relatively brief answers.

> 1.  How can I use the third link for default routes?  Is static routing
>     the only solution?

You could speak BGP with all links and balance that way - and tune to
prefer certain ASNs through the MCI links to reflec the fact that the
path to MCI is 2xT1.

But 3 load-balanced default routes would do easy load-balancing (though
it'd often send MCI traffic to UUNET and vice versa, which is obviously
suboptimal).  Of course, you nail the CPU {more} on a Crisco if you turn
off ip route-caching so that you can do load-balanced default routes.

> 2.  Is it possible to load-share outgoing traffic between two different
>     ASN's?  How?

See above, or the location that Paul referenced for more info about
tuning outbound data by changing how you hear BGP routes.

> 3.  How can I unclude the third link for load-sharing incoming traffic?

Just start speaking BGP.  If you get too little from UUNET, you can pad
your AS announcement once towards MCI, but that might bring too much 
traffic in UUNET.  

> Thanks,

> Michael R. Poyaoan                        email:  mrp at skyinet.net

Avi