[arin-ppml] 4-Byte ASN's in the ARIN region...

Jeff Wheeler jsw at inconcepts.biz
Thu Mar 15 15:11:08 EDT 2012

On Wed, Mar 14, 2012 at 12:09 PM, John Curran <jcurran at arin.net> wrote:
>  I've been asked why 4-Byte ASN's don't seem work in the ARIN region, but
>  do seem to work all of the other regions.

I still find it common for transit providers to react with a "we don't
support..." and similar.  I suppose they will stop doing this when
their customers are no longer able to get a 2 byte ASN because they
have been exhausted, or when two or three more years go by and
substantially all non-supporting routers/software has finally reached
the end of its useful life.

On the other side of the coin, I found my clients unwilling to upgrade
router software (a simple matter of an outage window for reboot)
simply to gain 4 byte ASN support given that customers had an easy
time changing to a 2 byte ASN by going back to the RIR.  I really
don't have a strong opinion on if this is good or bad behavior.  Why?

The BGP community issues related to 4 byte ASN are still not resolved
and likely won't be very soon.  The IETF community, and more so,
vendors, really screwed the pooch on ASN exhaustion.  We still don't
have the community tools we need and it's pretty unfortunate that a
problem which was easily predicted in the 90s is still an issue for
new network operators in 2012.

If there was a way to modify current ARIN policy or practice so that
networks could not exchange a 4 byte ASN for a 2 byte ASN unless they
were connecting to an IXP, I think that would encourage the remaining
networks who have not supported 4 byte ASN to do so, while also not
penalizing folks who participate in peering at public exchanges where
there remain some legitimate technical problems.

Jeff S Wheeler <jsw at inconcepts.biz>
Sr Network Operator  /  Innovative Network Concepts

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