Start accepting longer prefixes as IPv4 depletes?

James Hess mysidia at
Wed Dec 8 21:23:40 CST 2010

On Wed, Dec 8, 2010 at 5:08 PM, Iljitsch van Beijnum <iljitsch at> 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.


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