Question on peering strategies

Owen DeLong owen at
Mon May 23 16:50:34 UTC 2016

As mentioned by others, they do exist, but usually not for exactly the reason you state.

In most cases, peers go to PNI instead of peering via the exchange when it does not make
sense to grow laterally at the exchange for significant bilateral traffic. It’s much
less expensive to get a cross-connect from my router to your router than for both of
us to add a cross-connect to the exchange and each pay for an additional exchange port.

Example: If I have 12.5 gigs of traffic to the exchange and 8 gigs of that is to
autonomous system X while the remaining 4.5 G goes to random other peers, then it
makes much more sense for both X and I to connect directly (PNI) than for each of
us to order an additional exchange port to support that traffic.


> On May 21, 2016, at 23:33 , Max Tulyev <maxtul at> wrote:
> Hi All,
> I wonder why a "VLAN exchange" does not exists. Or I do not know any?
> In my understanding it should be a switch, and people connected can
> easily order a private VLAN between each other (or to private group)
> through some kind of web interface.
> That should be a more easy and much less expensive way for private
> interconnects than direct wires.
> On 16.05.16 20:46, Reza Motamedi wrote:
>> Dear Nanogers,
>> I have a question about common/best network interconnection practices.
>> Assume that two networks (let's refer to them as AS-a and AS-b) are present
>> in a colocation facility say Equinix LA. As many of you know, Equininx runs
>> an IXP in LA as well. So AS-as and AS-b can interconnct
>> 1) using private cross-connect
>> 2) through the public IXP's switching fabric.
>> Is it a common/good practice for the two networks to establish connections
>> both through the IXP and also using a private cross-connect?
>> I was thinking considering the cost of cross-connects (my understanding is
>> that the colocation provider charges the customers for each cross-connect
>> in addition to the rent of the rack or cage or whatever), it would not be
>> economically reasonable to have both. Although, if the cross-connect is the
>> primary method of interconnection, and the IXP provides a router-server the
>> public-peering over IXP would essentially be free. So it might makes sense
>> to assume that for the private cross-connect, there exists a back-up
>> connection though the IXP. Anyway, I guess some discussion may give more
>> insight about which one is more reasonable to assume and do.
>> Now my last question is that if the two connections exist (one private
>> cross-connect and another back-up through the IXP), what are the chances
>> that periodically launched traceroutes that pass the inter-AS connection in
>> that colo see both types of connection in a week. I guess what I'm asking
>> is how often back-up routes are taken? Can the networks do load balancing
>> on the two connection and essentially use them as primary routes?
>> Best Regards
>> Reza Motamedi (R.M)
>> Graduate Research Fellow
>> Oregon Network Research Group
>> Computer and Information Science
>> University of Oregon

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