[139048] in North American Network Operators' Group
Re: Regional AS model
daemon@ATHENA.MIT.EDU (Owen DeLong)
Fri Mar 25 15:47:32 2011
From: Owen DeLong <owen@delong.com>
In-Reply-To: <87675028-2B60-4A52-8EC7-0CDD010CEAF8@pch.net>
Date: Fri, 25 Mar 2011 12:45:14 -0700
To: Bill Woodcock <woody@pch.net>
Cc: NANOG list <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Mar 24, 2011, at 2:26 PM, Bill Woodcock wrote:
>=20
> 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
>>> 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.
>> Single AS worldwide is fine with or without a backbone.
>> Which is "preferable" is up to you, your situation, and your personal =
tastes.=20
>=20
>=20
> We're with Patrick on this one. We operate a single AS across =
seventy-some-odd locations in dozens of countries, with very little of =
what an eyeball operator would call "backbone" between them, and we've =
never seen any potential benefit from splitting them. I think the =
management headache alone would be sufficient to make it unattractive to =
us.
>=20
> -Bill
>=20
>=20
>=20
>=20
>=20
To be clear, when I said backbone, I meant that if a packet arrives at =
site A destined for site B, it goes across
some form of internal path and not back out to the internet. That Site A =
and Site B learn each other's routes
via iBGP and not via third-party ASNs.
If A learns B's addresses from a third party ASN, then, it is highly =
desirable (IMHO) to have A and B in
separate ASNs.
Owen
