Sending vs requesting. Was: Re: Sprint / Cogent

Scott Berkman scott.berkman at
Sun Nov 2 03:00:56 UTC 2008

I really doubt Sprint's purpose here is to "hurt the Internet" or to harm
Cogent either in terms of costs or reputation.

Here are my views on the topic:

	Every time Cogent gets de-peered (at least 5 times now since
2003), this discussion comes up again and it seems that some people forget
(or don't know) how many times it's happened to them before.  There must
be a reason it keeps happening, right?  Are there any other large ISPs
that have had this type of problem 5 times?

	As someone was saying earlier, in the PSTN world carriers
generally pay for every call terminated to another carrier's network and
pay each other back and forth.  In IP peering, these types of costs are
"eliminated" by settlement-free peering relationships where carriers feel
there is a benefit to do so.

	These are relationships or contracts between the two carriers, and
most of us have no idea how these are written or what clauses are included
about how and when one carrier can end that contract.  Regardless of the
exact terms, there will certainly be actions or other situations that
would be viewed as a breach of contract, resulting in ending or changing
the relationship.

	In the case of Cogent, they seem to want to be a Tier 1 carrier
(usually loosely defined as an carrier that does not pay for transit or
access from/to any other carrier), but they are not usually considered one
by many in the industry.  Technically at this point they are not since
they are believed to pay Level 3 and Sprint.

	Now I really can't speak to exactly why each carrier that has
de-peered Cogent in the past has done so, but based on conversations I've
had with higher-ups at one of these ISPs, their major issue with Cogent
was a huge discrepancy in the volume of inbound vs. outbound traffic.  To
that carrier, based on the traffic patterns, they believed that Cogent
should be paying for their connections and was not keeping to the spirit
of their relationship or breaking the contract if there was one.  They
supposedly attempted for some time to resolve the issue amicably, but when
that failed they chose to take action as a last chance to resolve the
dispute to their liking.

	Now as to the "harmful" effect to Cogent's customers, that effect
would be easily mitigated if Cogent would choose to buy transit from any
other ISP.  Instead, they try to avoid that by offering affected customers
free circuits for some period of time, which hopefully turn into paying
customers at a later date.  Also, anyone running any important site or
network knows never to be single-homed, and therefore should not be
effected in the long run.  Anyone single homed accepts the risks
associated with that by not having redundant connections, especially if
that single home is Cogent based on their history of peering arguments.

	So based on that the only "difference" I'd expect this to make is
in the relationship between Sprint and Cogent in the future.  I doubt this
will change Sprint's, Cogent's, or any other ISP's corporate
views/policies on peering in the long term.

	Just my 2 cents,


-----Original Message-----
From: Matthew Moyle-Croft [mailto:mmc at] 
Sent: Saturday, November 01, 2008 10:07 PM
To: bas
Cc: nanog at
Subject: Re: Sending vs requesting. Was: Re: Sprint / Cogent

bas wrote:
> Why does everyone keep referring to traffic flows as sendng?
> In this case it's not as if Cogent just randomly sends data to Sprint.
I think it's a really odd reinterpretation of telephony concepts.   In 
telephony interconnects are typically settlement based, sender pays 
receiver, in the settlement based world it seems to have gotten confused.

I'm still trying to come to terms with what Sprint is trying to achieve 
here.  I can only assume it's (and I'm stealing from Vijay here) to 
raise Cogent's cost of doing business by forcing them to do settlement 
based or paid peering and thus trying to force the cost of their transit 
to rise.  Maybe it's to damage Cogent's reputation as well?  The cost of 
doing this seems to be high (ie. upsetting high paying (single homed) 
transit and mobile customers) and getting negative media coverage. 

Is this really going to make a substantial kind of difference?


Matthew Moyle-Croft - Internode/Agile - Networks

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