Arbitrary de-peering

Jon Lewis jlewis at
Mon Jul 28 16:27:18 UTC 2008

On Mon, 28 Jul 2008, William Waites wrote:

>> Neither network has transit.  What other path is there to take?

Bit bucket path.

> "Then Cogent de-peered Telia and suddenly Verizon and others started 
> providing a path
> between the two and their respective customers."
> Which is as it should be. Then somebody (not clear who) apparently took 
> explicit steps to stop the traffic from taking these other paths. 
> Surprising. Severing a peering relationship is one thing, purposely 
> filtering large swathes of the Internet over other all links is quite 
> another.
> As I said, this is surprising behaviour, but not simple de-peering. And I'm

Why is it surprising?  Sounds more like a repeat performance to me.

Back when Level3 depeered Cogent, it was said that Cogent was already 
buying transit from Verio to reach at least some networks they weren't 
peering with.  After the depeering, why didn't Cogent get to Level3 (and 
vice versa) via Verio?

Was the reason ever made public?

> Tier 1 has enough peering relationships with enough other Tier 1 
> networks that they can always buy temporary transit privileges over an 
> existing link.

Tier 1 means you don't buy transit, no?

  Jon Lewis                   |  I route
  Senior Network Engineer     |  therefore you are
  Atlantic Net                |
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