Question about peering

Sat Apr 7 23:25:24 UTC 2012

"Luke S. Crawford" <lsc at prgmr.com> writes:

> On Sat, Apr 07, 2012 at 06:16:30PM -0400, Robert E. Seastrom wrote:
>> Sometimes making the AS path as short as possible makes a lot of sense
>> (e.g. when trying to get an anycast network to do the right thing),
>> but assumptions that peering results in lower costs are less true
>> every day.
>
> I keep reading people say that.  But wouldn't the same forces that push 
> down the per-megabit cost of transit also push down the per-megabit
> cost of peering?  

Generally the costs of transit are pushed down by competition.  As a
vendor your costs for bandwidth/transport/port*bw may drop but you are
unlikely to drop your prices to your customers merely because your
costs have gone down unless prompted to by a competitor.

In any given IX, cross-connect fibers and peering switch ports are
often a monopoly.  While not unheard-of for there to be two competing
IX switch fabrics available in a single facility, the cross-connects
to those competing exchanges are not free, and I'm not aware of any
sizeabe facilities that are still "run your own XC and don't pay
anyone for it" (of course, as soon as I say that I'll get private
email or an IRC message pointing out the corner case).

Consider the case of a peering n00b network (the target of this
discussion after all) in hypothetical facility that charges
$1000/month for a gigabit ethernet port on the peering fabric.  You
turn up a connection to this port and discover that (without buying
people drinks / sushi dinners / etc at a conference) you can bring up
enough peering with other networks to move 150 Mbit/sec on it.  That's
pretty optimistic for a small player, but still...  now you're paying
$6.66/mbit for that transit.  If you can move 150 Mbit/sec to
low-hanging-fruit transit you're probably between 1 and 2gbps total.
How's that compare with what you're paying for transit with that level
of commit?

-r