Exchanges that matter...

Vadim Antonov avg at
Fri Dec 6 00:25:04 UTC 1996

Wayne Bouchard <web at> wrote:

>Actually... many of the private exchanges are there for several other
>reasons as well. First, it can be convenient to set up a connection
>with a net you're passing lots of traffic to so you can go direct to
>them instead of through 7 or 8 odd routers outside your
>net. (obviously)

We were talking about tier 1 exchanges (i.e. between nation-wide and
world-wide backbones).  They by definition pass a lot of traffic between
each other.

>Second, it can be significantly cheaper to split the costs between the
>participants and not have to pay a third party for access to the
>exchange. (heck of a lot easier too..)

Well, if you have 6 providers you'll need 15 private two-party exchanges
to accomodate full connectivity in a region, vs a single public facility.

It is a classical example of economies of scale.  Consolidation of
exchange facilities makes things a lot cheaper. (Providing there's a way
to sustain that much traffic in one place).

>Third, and going along with the first point, private exchanges can
>help to more geographically orient your local corner of the
>network. That way, to get across town, you don't have to go to
>mae-west, over to denver, and back down to phoenix to travel 6 miles.
>This also serves to take a little traffic AWAY from the public NAPs
>and can help reduce congestion and problems there.

That would be fine, if traffic had high locality.  As is, practically
all Internet traffic is long-haul.  I.e. i strongly doubt benefits of
micro-exchanges will outweigh their drawbacks.

>The principle disadvantage of lots of small exchange points, as far as
>I see it, is that there may well be potential for A) many more paths
>to get from A to B, meaning that each router will hold that many more
>BGP entries and B) possibly a greater potential for route flap.

C) a lot more facilities not generating revenue.


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