Peering - Benefits?

Tomas L. Byrnes tomb at
Fri Oct 31 02:34:00 UTC 2008

As with all things, this isn't so cut and dried as everyone makes it
seem. The OP was asking for an easy answer to a complex question, which
usually shows a lack of understanding of the issues, or is an attempt to
provoke controversy.

So far, most of the discussion has focused on peering as a substitute
for transit.

The idea behind peering is not that the peer takes your traffic destined
for other networks, but that you each deliver the traffic destined for
each other directly, without the need to transit. 

This should save BOTH of you $ on transit, reduce routing complexity for
the peered networks, make troubleshooting traffic issues between the
networks easier, and improve user experience.

Common examples of where peering makes a lot of sense are:

Major hosting providers to major national end-user networks.

CDNs to end-user networks.

Local data centers and DR facilities to metropolitan Ethernet providers.

Hosting facilities to networks that service certain specific user
communities, such as local realty MLS systems to the local cable and DSL

If you're using peering for transit, you're kind of missing the point,
and introducing a lot of potential network (route leakage or excessive
route prepends) and business (at what point does a transit imbalance
become unfair) problems.

IMO, peer for direct delivery, use transit for all else.


>-----Original Message-----
>From: vijay gill [mailto:vgill at]
>Sent: Thursday, October 30, 2008 7:20 PM
>To: Paul Stewart
>Cc: nanog at
>Subject: Re: Peering - Benefits?
>This is probably going to be a somewhat unpopular opinion, mostly
>because people cannot figure out their COGS. If you can get transit
>for cheaper than your COGS, you are better off buying transit and not
>peering.  There are some small arguments to be made for latency and
>'cheap/free' peering if you are already buying transit at an exchange
>and your port/xconn fee is cheaper than your capital/opex for the
>amount of traffic you peer off.
>To be completely realistic, at current transit pricing, you are almost
>always better off just buying transit from two upstreams and calling
>it done, especially if you are posting to nanog asking about peering.
>On Wed, Oct 29, 2008 at 12:17 PM, Paul Stewart
><pstewart at> wrote:
>> Hi there...
>> I'm in a meeting next week to discuss settlement-free peering
>> always an interesting time.  A push is on (by myself) to get into
>> physical locations and participate on the peering exchanges.
>> Besides costs, what other factors are benefits to peering?
>> I can think of some but looking to develop a concrete list of
>> reasons etc. such as:
>> -control over routing between networks
>> -security aspect (being able to filter/verify routes to some degree)
>> -latency/performance
>> Just looking for other positive ideas etc...;)
>> Cheers!
>> Paul
>> "The information transmitted is intended only for the person or
>to which it is addressed and contains confidential and/or privileged
>material. If you received this in error, please contact the sender
>immediately and then destroy this transmission, including all
>attachments, without copying, distributing or disclosing same. Thank

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