New peering criteria [ and Enron ]

Geoff Huston gih at telstra.net
Thu Jun 7 11:05:07 UTC 2001


At 6/7/01 07:21 AM, James Thomason wrote:

> > I agree, but how do you decide who is hurt more?
> >
> > And therefore who should be the vendor and who is the customer?
> >
> > Is the "bigger" network always the vendor, or is the network with more
> > content the vendor, or the network with more eyeballs the vendor?  That's
> > what I don't understand about the "balance" requirement.  Ok, so you know
> > the traffic is imbalanced, but whose fault/hurt is it when traffic is
> > imbalanced?  And who is responsible for "fixing" the imbalance in traffic?
>
>In the telecommunications industry the role of "vendor" is played mutually
>depending on the initiation of the transaction.  The finite start and
>stop point (or "call minute" as Geoff Huston referes to it) allows
>exchanging parties to assign cost for a specific transaction and a
>specific time.

Since I've been quoted in this stream, maybe I should humbly offer a few 
opinions masquerading as observations ( :-) )

The peering game has no real objective rules - its a game that is played 
out in the jungle every night - you see a pair of eyes a few inches in 
front of you - should you try to eat it or try to get away? Unfortunately 
there's not enough information to make a rational choice, so you would 
normally run away, but if you are also hungry at the same time.....

The interactions in the inter-Provider space tend to work out to one of 
three outcomes:

   1 Either A pays B unconditionally (and becomes a customer of B)
      (and, yes, this includes 'paid peering')

   2 A and B do not interconnect directly, and resolve connectivity through 
third party interactions

   3 A and B interconnect and agree not to pay each other - i.e. peering

There's simply not enough information at the packet header level (the 20 
bytes of IP header) to calculate a 'true' value transfer per packet passed 
between the two providers, so the call minute arrangement calculation used 
in the PSTN is simply not an option here. Instead, you inevitably arrive at 
one of the three outcomes above.

Peering is a game of working out that there is perceived equity in the 
benefits of the arrangement. Sometimes this is established as equity of 
denial - i.e. if both parties are equally disadvantaged by NOT 
interconnecting directly, then peering is a logical outcome. If one party 
is perceived as being more disadvantaged by such an outcome, and both 
parties can privately admit to themselves that this is the outcome, then 
that party becomes the customer of the other, if they interconnect.

The issue is one of figuring out equity of perceived benefit. If A works 
out that the benefit to A is $10 and its calculation of the benefit to B is 
$10, and _at the same time_ B undertakes a similar calculation and works 
out that the benefits to A is $20 and the benefit to B is $20, peering is 
still a stable outcome. Even if A works out that it is better off than B 
AND at the same time B works out that it is better off than A as a result, 
then peering is still a stable outcome.

Over time A and B change their perception of their own value and their 
perception of the value to the other party. If A and B are peering, then A 
naturally wants to create a situation where if can force B to become a 
customer, and B has precisely the same motivation. The forcing function 
used is sometimes one of disconnection.

Sometimes its a three or more party game - to demonstrate that A no longer 
relies on B's transit services, A may become a customer of C and then 
approach B for peering. If A can negotiate a peering relationship with B on 
this basis, A can subsequently renegotiate its arrangement with C. And so 
on and so on...

Its not a bad trading market, as trading markets go. Open information of 
trade outcomes is available in the BGP table, so that the market can be 
considered to be a well informed market even though individual negotiations 
and outcomes are private. Its an interesting outcome to consider the BGP 
table as the stock exchange listing service of the inter-provider trading 
market.


Geoff




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