North American Network Operators Group

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Re: Level 3's side of the story

  • From: Stephen J. Wilcox
  • Date: Sat Oct 08 16:19:47 2005

On Sat, 8 Oct 2005, Eric Louie wrote:

> DISCLAIMER:  From one of the clueless
i'm not picking on you as theres a huge amount of misinformation being posted on 
this thread but perhaps a private email to someone with questions might be 
better. having said that, perhaps this will serve to educate..

> During this entire debaucle, I never saw any mention of:
> 1)  Cogent sending "transit" traffic to Level3, which leads me to believe that
> all the traffic from Cogent through the peering points was actually *destined*
> for Level3 customers.  Does the routing support this idea?  Is it safe to
> assume the opposite, also... that only traffic destined for Cogent customers
> came through the Level3 peering points?  And that Level3 had one and only one
> path to Cogent (no one else providing transit for them to Cogent AS'es?)

peering is all about exchanging bgp on your customers with the peer, it excludes
sending routes from another peer which is usually called transit

> 2)  Level3 making any contingency for their own customers to reach Cogent
> networks (any announcements to their own customers)

understand the inability to reach cogent was the desired result for level3, had 
a contingency been put in place level3 would have been heading in the opposite 
direction to which they are moving (they are moving to force cogent to buy 
transit, not moving to pay for their connectivity to cogent nor to keep the 
current settlement free arrangement)

> 3)  Possible traffic issues.  Was Cogent guilty of not transporting the 
> Level3-bound packets within the Cogent network to the closest point-of-entry 
> peer to the host in the Level3 network, therefore "costing" Level3 transit 
> of their own packets?  In other words is it also a traffic engineering 
> issue?

cogent has not got a transit provider giving them level3 routes (as far as we 
understand) and they have not gone and setup any such transit arrangement whilst 
waiting for the depeering.

it is not allowed for you to send traffic to another network via a peering. so
eg if you peer with me we will send you only our customer routes, if you
forcibly get cogents routes and route them over us without our permission you
are stealing bandwidth and we will either depeer, sue, or both. to obtain this 
'permission' would mean us acting as a transit for you and we'd probably want 
some money to do that. (consider i do not exchange money with my peers, if one 
peer uses me to reach another peer nobody is paying me for the use of my 

> Are some of the business issues solvable by proper engineering and filtering
> (or statistics-jockeying)?

short answer: no, this is a political and business problem not one of 

longer answer: level3 may be claiming that either cogent has insufficient 
traffic, that it has too much outbound or that it isnt in enough geographic 
locations. cogent could invest money to comply with level3s peering requirement. 
but this ultimately results in cogent spending money either to meet a new 
peering requirement or paying level3 direct to maintain a settlement peering.


> ----- Original Message ----- 
> From: "Jon Lewis" <[email protected]>
> To: <[email protected]>
> Sent: Friday, October 07, 2005 9:45 PM
> Subject: RE: Level 3's side of the story
> >
> > On Fri, 7 Oct 2005, David Hubbard wrote:
> >
> >>> I don't remember seeing this public notice from Level(3) posted....
> >>> Wouldn't that be "without notice from Level(3)"?
> >>
> >> They notified Cogent, not the public.  Cogent chose to
> >
> > I think it's also interesting, that AFAIK, Level3 didn't give their own 
> > customers any advance notice.  We're a customer.  I saw nothing about this 
> > until it hit nanog.  We're multi homed, so the impact on us was unnoticed.
> >
> > Suppose you're a single homed L3 or Cogent customer doing regular business 
> > with a single homed Cogent or L3 customer.  If your provider gave you 
> > several weeks notice, and if you realized the coming problem, you might 
> > take some steps to work around the issue, depending on how important your 
> > internet communications are.  Do the typical peering NDAs forbid giving 
> > customers this sort of notice?  Is it better to surprise them with a 
> > multi-day outage and then give them 30 days notice that it's going to 
> > happen again??
> >
> >>> Splendid, that gives the world sufficient time to accept
> >>> Cogent's offer of 1 year free service.
> >>
> >> This is not the first time Cogent has used their customers
> >> as pawns in peering disputes, I don't know if I'd jump on
> >> the bandwagon so quickly (spoken as a customer of both
> >> companies).
> >
> > If you're multihomed and using Cogent as a cheap bandwidth whore, does it 
> > matter if their cheap bandwidth gives you 155k routes instead of 168k 
> > routes?  After all, if its cheap and off-loads enough traffic from your 
> > more expensive 168k route circuits, isn't it doing what you bought it for?
> >
> > Also, is 30 days really enough time for anyone to get a free connection to 
> > Cogent?  I mean if you're in a building they're already in, and its just a 
> > cross connect, sure that can be done quickly...but at least around here, 
> > getting any sort of high bandwidth circuit (>T1) can take months.  IIRC, 
> > the UNE DS3 connecting our office to the rest of our network was several 
> > months late.
> >
> > ----------------------------------------------------------------------
> >  Jon Lewis                   |  I route
> >  Senior Network Engineer     |  therefore you are
> >  Atlantic Net                | _________ 
> > for PGP public key_________
> >
> >
> > -- 
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> >