On Wed, Dec 8, 2010 at 5:08 PM, Iljitsch van Beijnum <iljit...@muada.com> wrote: > On 8 dec 2010, at 23:48, Jack Bates wrote: >> I'm going to go out on a limb (and not read the last BGP summary reports) >> and say that ISPs being assigned fragmented space has caused more routing >> table bloat than deaggregation for traffic engineering. > > Why would ISPs get fragmented space? The RIRs are still getting /8s from IANA > at the moment. > And most deaggregation is not for traffic engineering because the attributes > are all the same.
Because ISP networks are not fixed sized entities that never add more infrastructure (or more customers), like some end users might be. ISPs get contiguous assignments, but when they later require more IP address space, they apply for more space, and wind up with a new assignment that is not aggregable with the previous assignment(s). The RIRs do not predict their members' future requirements, and maintain enough unallocated buffer space around allocations to provide a contiguous extension when more address space is requested. -- -JH
