32 bits ASN on Cisco

Sun Apr 11 16:44:43 UTC 2010

There's quite a bit of hardware that does support it, including JunOS
since 9.1 (I believe). But there's still a few lagging platforms
(especially on the Cisco side) that does not yet support it.  IOS 15
does indeed support it, so there is support for it in mainline code on
the smaller routers. It's just that a few key platforms are still
missing it (or the code is too new to be useful). Keep in mind, the
2500's and I believe the 2600's have been EOL'd for quite some time
now, so you will never likely see support for those platforms.

GG

On Sun, Apr 11, 2010 at 6:15 AM, Franck Martin <franck at genius.com> wrote:
> 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 at snickers.org>
> To: "Franck Martin" <franck at genius.com>
> Cc: nanog at 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_N45.pdf
>
> GG
>
>
>