Abstract: D(3)peered: Just the Facts Ma'am

Alin Popescu and Todd Underwood, Renesys

Recent depeerings by Level (3) (AS3356) of XO (AS2828) and Cogent (AS174) have captured the attention of the network operations community, due to the resulting partitioning of major Internet backbones. The depeerings have also captured the attention of the mainstream press and politicians. Very little of the public commentary, however, has been based on facts regarding the routing. Using a large, globally distributed peerset, we look specifically at the Cogent depeering. We characterize the weight of the 3356_174 edge (in both directions) in terms of prefixes announced and prefixes commonly selected, the single-homed downstreams of each, and try to describe the actual impact of the depeering on Internet accessibility for customers of both networks.

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