On Sat, 8 Sep 2007, Lincoln Dale wrote:
what i think it boils down to is that many folks seem to run default-free because they can, because its cool, because its what tier-1 folks do, because (insert cool/uber reason why here), but not necessarily because they HAVE TO.
Consider a regional or local ISP providing BGP to a customer. The customer also has a connection to a "Tier 1". The customer may start asking questions when they notice they get 250k routes from one provider and only 50k to 80k less routes from you. I suppose some "Tier 1"s got away with this in the past though...so maybe there are acceptable answers.
even if you're a content-provider in North America and want to ensure an "optimal path" of traffic, generally speaking, you could accept prefixes (as-is) from ARIN allocations but for (say) APNIC and RIPE do either some degree of filtering or just push it via a default.
I actually suggested this yesterday to a friend who runs an ISP and has just run into his 7500s running out of RAM and crashing when turning up a new transit provider with full BGP routes. Filtering the APNIC and RIPE regions and adding a default will very likely let him fit "mostly full routes" on his router and put off the inevitible fork-lift upgrade a while longer. ---------------------------------------------------------------------- Jon Lewis | I route Senior Network Engineer | therefore you are Atlantic Net | _________ http://www.lewis.org/~jlewis/pgp for PGP public key_________