[c-nsp] ISP Dual AS

[Justin M. Streiner]

On Thu, 6 Dec 2012, mert ozkul wrote:

> I have query about ISP Design.
> Why some ISP`s (Ex: BT) using dual AS`es on their network?
> What are the advantages of using more than one AS in the ISP 
> network?What can be achieved if you use more than one AS?

At my previous job, I ran a network that was composed of as many as 5 ASNs 
for a while.  The reason is that my employer acquired several other ISPs 
in a fairly short time.  Eventually, most of them were brought under our 
'main' AS, but a few were still kept separate because the 
expense/difficulties in getting sufficient internal bandwidth to those 
sites made integrating them a bit more of a challenge.

jms