[139047] in North American Network Operators' Group
Re: Regional AS model
daemon@ATHENA.MIT.EDU (Owen DeLong)
Fri Mar 25 15:39:35 2011
From: Owen DeLong <owen@delong.com>
In-Reply-To: <8F562261-1B99-46EC-B4D0-F9665C3DAFD9@ianai.net>
Date: Fri, 25 Mar 2011 12:33:53 -0700
To: "Patrick W. Gilmore" <patrick@ianai.net>
Cc: NANOG list <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Mar 24, 2011, at 1:47 PM, Patrick W. Gilmore wrote:
> On Mar 24, 2011, at 3:40 PM, Owen DeLong wrote:
>> On Mar 24, 2011, at 12:42 PM, Zaid Ali <zaid@zaidali.com> wrote:
>>=20
>>> I have seen age old discussions on single AS vs multiple AS for =
backbone and datacenter design. I am particularly interested in =
operational challenges for running AS per region e.g. one AS for US, one =
EU etc or I have heard folks do one AS per DC. I particularly don't see =
any advantage in doing one AS per region or datacenter since most of the =
reasons I hear is to reduce the iBGP mesh. I generally prefer one AS =
and making use of confederation.=20
>>>=20
>>> Zaid
>>=20
>> If you have good backbone between the locations, then, it's mostly a =
matter of personal preference. If you have discreet autonomous sites =
that are not connected by internal circuits (not VPNs), then, AS per =
site is greatly preferable.
>=20
> We disagree.
>=20
> Single AS worldwide is fine with or without a backbone.
>=20
Only if you want to make use of ugly ugly BGP hacks on your routers, or, =
you don't care about Site A being
able to hear announcements from Site B.
> Which is "preferable" is up to you, your situation, and your personal =
tastes. (I guess one could argue that wasting AS numbers, or polluting =
the table with lots of AS numbers is bad or un-ashetically pleasing, but =
I think you should do whatever fits your situation anyway.)
>=20
I don't see any significant downside to AS number consumption given a =
32-bit AS Number space.
I do see significant downsides to disabling BGP loop detection.
Owen
