Regional AS model

Bill Woodcock woody at
Thu Mar 24 16:26:35 CDT 2011

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 at> wrote:
>>> 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. 
>> 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.
> 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. 

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.


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