[arin-ppml] Request for staff: 4-byte ASN data

[Richard Jimmerson]

Hello David,

Thank you for your inquiry about 4-byte AS number registration data at ARIN.

For the last several years ARIN has been registering AS numbers by issuing the lowest AS number we have in inventory to approved organizations. We ask those organizations if they would be willing to accept an AS number higher in the number range, and outside of the range that previously made up the 2-byte only AS number space.

In 2014 we found that nearly 27% of the organizations approved for an AS number elected to receive a 4-byte AS number rather than take the lowest AS number in our inventory. Several organizations unwilling to receive a 4-byte AS number have indicated to ARIN that their transit providers strongly state a preference that their customers use AS numbers from the traditional 2-byte AS number range.

More recently, because of a lack of 2-byte AS numbers in the ARIN inventory, the AS number assignments we make are 4-byte AS numbers and outside of the range that previously made up the 2-byte only AS number space. For those organizations who come back to ARIN specifically stating a preference for a 2-byte AS number, we may be able to continue satisfying their requests using AS numbers that have recently been added to the ARIN AS number inventory through returns or revocations. Very recently ARIN received a new assignment of AS numbers from the IANA. Roughly 90 of those were from the 2-byte range.

In 2014 there were 12 organizations that elected to receive a 4-byte AS number and later came back to ARIN to exchange it for a 2-byte AS number. Each of these organizations stated issues with their transit providers either unwilling or unable to accept the use of a 4-byte AS number by a customer.

2014 total AS numbers issued:  1,579
2014 4-byte AS numbers issued:  416
2014 2-byte AS numbers issued:  1,163

Thank you again.

Richard Jimmerson
CIO & Acting Director of Registration Services
American Registry for Internet Numbers



From: David Huberman <David.Huberman at microsoft.com<mailto:David.Huberman at microsoft.com>>
Date: Friday, May 15, 2015 at 11:22 PM
To: "ARIN PPML (ppml at arin.net<mailto:ppml at arin.net>)" <ppml at arin.net<mailto:ppml at arin.net>>
Subject: [arin-ppml] Request for staff: 4-byte ASN data

Staff,

The 4-byte ASN vs. 2-byte ASN debate is raging in the RIPE address policy working group.  In conversations with folks off-line, we’ve been trying to gauge how much of a problem the lack of 4-byte ASN support from some vendors is for smaller networks.  We know that big guys have problems with some gear not supporting advanced feature sets, but it’s much harder to get good data on how bad (or not) the little network operators have it.

Some time back, ARIN produced stats on the number of exchanges – a situation where ARIN would issue a 4-byte AS number to a requestor, and then some weeks or months later, the requestor would return to ARIN and ask ARIN to exchange the 4-byte ASN for a 2-byte, because ‘the 4-byte ASN didn’t work”.

Can we have some insight into the last 12 months of data on this? Specifically:

How many 4-byte ASNs were issued?
How many have been exchanged for a 2-byte ASN?
Is there any anonymized colloquial data you can share that seems common among exchangers/requestors?

Thank you kindly.
David

David R Huberman
Principal, Global IP Addressing
Microsoft Corporation

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