Thus spake "Dino Farinacci" <dino@cisco.com>
It's unfortunate that it wouldn't change, because the provider would need to know about both the PA allocation and the EID assignment.Effectively, it's double the hassle factor.The provider doesn't have to know about EID-prefixes. It can filter and uRPF on the locator address that is part of it's own block.
Packets coming out of a LISP site will have a source address in the EID prefix if they're headed to a non-LISP site or depending on a PTR or ISP-provided ITR to reach other LISP sites; all of those cases give you uRPF or filtering problems. Packets will only have a source address in the RLOC prefix if they've been encapsulated by a customer ITR for transmission to another LISP site -- and we must assume that will be rare, at least initially. Tony is correct; the ISP now has to maintain routes (for uRPF) or filters for two prefixes per customer instead of one. OTOH, that is a cost paid in one place, while the benefit of LISP accrues to every BGP router with a full table. That seems like a reasonable trade-off... S Stephen Sprunk "God does not play dice." --Albert Einstein CCIE #3723 "God is an inveterate gambler, and He throws the K5SSS dice at every possible opportunity." --Stephen Hawking -- to unsubscribe send a message to rrg-request@psg.com with the word 'unsubscribe' in a single line as the message text body. archive: <http://psg.com/lists/rrg/> & ftp://psg.com/pub/lists/rrg