Question on peering strategies

[jlewis at lewis.org (Jon Lewis)]

On Mon, 16 May 2016, Reza Motamedi wrote:

> Hi Nick,
>
> Thanks for the reply.
>
> Let me clarify another issue first, since I thought the colo's business
> model is different at least in the US. So if AS-a puts its router in
> Equinix, it should pay the same amount in the following two scenario (only
> considering the interconnection cost and not the rent for racks and remote
> hands and ....)?
> 1) AS-a only connects to the IX and establishes all inter-AS connections
> through the IX.
> 2) AS-a connects to the IX, in addition to privately connecting to bunch of
> other colo customers (these private connections can be either transit or
> settlement-free peerings).
> My understanding was that colos in the US charge per cross connect, so the
> more you connect privately, the more you pay. This article may be old, but

Ports on the colo's IX, Equinix for example, will likely cost more than 
just a cross connect.  If you have peers with which you exchange enough 
traffic, it can make sense to remove that traffic from the IX and put it 
on PNI (cross connect) peering, leaving the IX port(s) for use primarily 
for peering with lots of "smaller peers" (in the amount of traffic 
exchanged).

Typically, if a peer is big enough to justify PNI, you won't want to 
fail-over to the IX as a backup, because doing so is likely to congest 
your or their IX links.  Of course, there are exceptions.  A PNI peer 
might not have enough ports to dedicate to PNI peering and might want to 
spread peering traffic over both PNI and IX evenly.

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