nanog mailing list archives

Re: PAIX


From: "Stephen Sprunk" <ssprunk () cisco com>
Date: Thu, 14 Nov 2002 13:32:55 -0600


Thus spake "E.B. Dreger" <eddy+public+spam () noc everquick net>
DD> 1) Long haul circuits are dirt cheap.  Meaning distance
DD> peering becomes more attractive.  L3 also has an MPLS product
DD> so you pay by the meg.  I am surprised a great many peers are
DD> using this.  But apparently CFOs love it

Uebercheap longhaul would _favor_ the construction of local
exchanges.

Incorrect.  Cheap longhaul favors a few centralized exchanges.  If there is no
economic value in keeping traffic local, it is in carriers' interests to
minimize the number of peering points.

Let's say I pay $100k/mo port and $10M/mo loop... obviously, I
need to cut loop cost.  If an exchange brings zero-mile loops to
the table, that should reduce loop cost.  Anyone serious will
want a good selection of providers, and the facility offering the
most choices should be sitting pretty.

Most vendor-neutral colos have cheap zero-mile loops.

Likewise, I agree that expensive longhaul would favor increased
local peering... but, if local loop were extremely cheap, would
an exchange be needed?  It would not be inappropriate for all
parties to congregate at an exchange, but I'd personally rather
run N dirt-cheap loops across town from my private facility.

What is the cost of running N loops across town, vs. the cost of pushing that
traffic to a remote peering location and back?  Be sure to include equipment,
maintenance, and administrative costs, not just circuits.

The above are "big bandwidth" applications.  However, they do not
inherently require exchanges... _local_ videoconferencing, yes.
Local security companies monitoring cameras around town, yes.
Video or newscasting, yes.

None of these applications require local exchanges.  There is a slight increase
in end-to-end latency when you must use a remote exchange, but very few
applications care about absolute latency -- they only care about bandwidth and
jitter.

Distributed content, yes.  (If a traffic sink could pull 80% of its traffic
from
a local building where cross-connects are reasonably priced...)

Distributed content assumes the source is topologically close to the sink.  The
most cost-efficient way to do this is put sources at high fan-out areas, as this
gets them the lowest _average_ distance to their sinks.  This doesn't
necessarily mean that putting a CNN mirror in 100,000 local exchanges is going
to reduce CNN's costs.

S


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