David Schwartz <davids@webmaster.com> wrote:

Not only would this increase the size of the global routing table, but this would actually decrease reliability for most basement multihomers. Basement multihomers tend to flap their routes more often than their upstreams. By not being inside a larger aggregate, these flaps are likely to result in more significant pockets of unreachability than they would be otherwise.

Have any of the major players ever tried cleaning up in the basement multihoming market? It seems to me that a pair of well positioned regional ISPs could easily share an aggregate, use it exclusively for multihomers thus alleviating the strain on the global routing table while giving their customers good visibility in the routing table. Tim