Middle Eastern Exchange Points

Wed Feb 8 17:30:25 UTC 2006

On Wed, 8 Feb 2006, Mikael Abrahamsson wrote:

> On Tue, 7 Feb 2006, william(at)elan.net wrote:
>
>> And when ISP A buys access from ISP B for purpose of getting to ISP C is 
>> that peering or transit?
>
> I thought it was generally accepted that "peering" is the exhange of routes 
> that are not re-sent to other organisations.

If I peer with you, you sent me your routes and routes for who you consider
to be your customer and if ISP C is your customer then ISP A by having
peering with ISP B gets access to ISP C.

> "Transit" is when one entity sends the routes on to other organsiations, 
> often with money involved.

More commonly understood is that transit involves one ISP sending all
of its BGP routes and allowing any traffic to be send from ISP A
for for delivery to destination.

However number of organizations (say cogent buying from verio) only
get routes from certain specific ISPs that they can not otherwise reach
which is again scenario  "ISP A buys from ISP B to get to ISP C" but
most people call this transit in this case...

The reality is that for outside observer (especially if you look at
the net as whole), there is no clear view that separates peering from
transit and most correct is to consider everything to be peering with
various differences being as to what kind of filters are deployed and
where and how money is being exchanged.

-- 
William Leibzon
Elan Networks
william at elan.net