Yes Gary, I understood how to run 16bit ASN with 32bit ASN, I'm just trying to confirm/understand how it is supported today on Cisco hardware. I have seen for instance policy change in APNIC, as since this year they assign 32bits ASN (which could fall in the 16bit part if you are lucky) but if you want a 16bit, then you need to justify. I feel this policy is a bit premature as hardware does not support it. I guess this exhaustion is not as critical as for IPv4, but still... To come back, to your statement that says it is just supported on 7200, means you cannot use a 32bit ASN in production today on any hardware? ----- Original Message ----- From: "Gary T. Giesen" <giesen@snickers.org> To: "Franck Martin" <franck@genius.com> Cc: nanog@nanog.org Sent: Sunday, 11 April, 2010 6:36:01 PM Subject: Re: 32 bits ASN on Cisco You can still request a 16 bit ASN from the registries, so if this is a concern for a new deployment you're not out of luck (yet). There is a compatibility mechanism, so you can still receive routes sourced from (or passing through) 32 bit ASNs, they will simply appear as AS 23456. Even if you have 32-bit ASN-compatible gear, all your direct peers need to support it as well (more or less), and many providers still don't have support for this yet (for example, the 7600 platform only just got support with 12.2(33) SRE0, and no one in their right mind is running it in production yet). A great resource for information on 32-bit ASN's is http://www.nanog.org/meetings/nanog45/presentations/Tuesday/Hankins_4byteASN... GG