On 6/7/10 11:51 PM:
Has anyone ever heard of a multi-homed enterprise not running bgp with
either of 2 providers, but instead, each provider statically routes a block
to their common customer and also each originates this block in BGP?
Yes, this is common and works fine. We do it with a number of customers who want a backup provider but don't want to go to the trouble of getting portable address space, an ASN, and so on. As long as both providers have a way of shutting down the advertisement (typically because they learn it via BGP) and as long as the customer doesn't try to load balance (i.e., treats it as active/passive not true active/active), then it's not a bad solution. Ugly, but given the vast chalice of despair that is the global BGP table, hardly a drop in the bucket.