Why don't ISPs peer with everyone?

Joel Jaeggli joelja at bogus.com
Tue Jun 7 12:12:01 UTC 2011

On Jun 6, 2011, at 12:53 PM, Justin M. Streiner wrote:

> On Mon, 6 Jun 2011, rucasbrown at hushmail.com wrote:
>> All the whole "don't peer with this guy" only makes your customers
>> have worse latencies and paths to other people, making the Internet
>> less healthy.
> Not necessarily.  Peering with an ISP who wants to take the traffic between your network and theirs through a saturated pipe, an overloaded router, or across an MPLS pipe with 13 underlying hops (each of which could be a choke point themselves) will not make your end-to-end latencies any better.
> As others have mentioned, some ISPs do have friendly peering policies. This is particularly true for ISPs that are co-located at the same IXP, because much of the opex is already baked into the ISP's relationship with the IXP.
> The reason most of the larger ISPs, particularly those who live in the DFZ, have peering policies (especially for settlement-free peering) that could be construed as less friendly to smaller networks is because those guys want to sell you transit, rather than let you peer for free, or for less than a the full transit rate.  It doesn't make financial sense for them to exchange bits with you for free, when they can make money off of those same bits if you buy transit instead.

carrying packets long distances cost more than carrying them short distances... large networks have an incentive to have the cost of that conveyance be reflected in peering relationship figuring out what if relationship makes sense in the marginal sense implies  both parties see mutual benifit.

> jms

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