North American Network Operators Group

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Re: Cogent/Level 3 depeering

  • From: Pete Templin
  • Date: Wed Oct 05 17:25:04 2005

Justin M. Streiner wrote:

Remember that when backbones peer with each other, they typically (and as normally dictated by peering policies on both sides) only announce their own routes and the routes of their downstream customers and agree not to announce a default route to each other. They do not announce a full routing table to each other. Upshot: When provider X de-peers provider Y, single-homed customers of either provider will likely have problems reaching single-homed sites of the other.
That assumes that both are transit-free networks. We've already heard that Cogent buys some form of fill-in transit from Verio, perhaps for a subset of {AOL/ATDN, Sprint, others}. Assuming such, why aren't routes appearing in L3's routers with paths matching _2914_174_? L3 might be filtering them out (automatically or manually; perhaps filters haven't auto-generated yet), or Cogent might be requesting that they be filtered (Verio's community structure allows this quite easily). Conversely, why aren't routes appearing in Cogent's routers with paths matching _2914_3356_? If Cogent is buying transit from Verio, they should be receiving a full table.

Anyone have any inside connections to expose the truth(s) here?