North American Network Operators Group

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Re: Cogent/Level 3 depeering

  • From: Joe Abley
  • Date: Wed Oct 05 15:27:39 2005

On 5-Oct-2005, at 13:43, Jeff Shultz wrote:

And why isn't this apparently happening automatically? Pardon the density of my brain matter here, but I thought that was what BGP was all about?

I welcome any education the group wishes to drop on me in this matter.
For most ISPs, normal practice is to advertise your own routes and those of your customers to your peers, and to your transit providers. To your customers, you advertise everything. If someone decides to stop peering with you, you reach them through one or more of your transit providers.

A relatively small number of providers are transit-free -- that is, they rely solely on customer and peering connections to reach the entire Internet.

When a transit-free ISP loses a peer, there is no transit path to fall back on.

While it's undoubtedly true that there are third parties who interconnect and peer with both cogent and layer(3), the fact that those are peering connections and not customer/transit connections means that the third parties are unlikely to advertise cogent routes to layer(3), and vice versa.

This is a money issue. ISPs don't generally give away transit for free.