Tag Archives : Add new tag October 2008

Trick or Treat: A Halloween Peering Surprise

By: Craig Labovitz -

Yesterday, tens of thousands of Sprint and Cogent customers got an early Halloween surprise. At 4pm EDT, Sprint and Cogent terminated their direct peering relationship.

The below graph shows traffic from the perspective of 25 tier2 ISPs around the world. All of these ISPs are direct customers of either Sprint or Cogent. And all lost transit connectivity from Cogent to Sprint (or vice versa). The graph shows all ASPaths matching “174 1239″ and “174 1239″ across these 25 providers. One minute several Gbps of traffic and then, well, poof.

Sprint - Cogent Traffic

For all but a couple of these ISPs, traffic quickly moved to alternative paths. Other ISPs like Verizon, Qwest, BT, and Level3 (who had their own peering dispute with Cogent last year) provided transit paths between the now partitioned two ISPs. Though, at least one ISP anonymously participating in the Internet Observatory lost connectivity to Sprint customers (and continues to drop traffic as of this blog posting). It pays to be multi-homed.

Why did Cogent and Sprint pull the plug on their peering relationship? I have no direct information, but money, traffic ratios, and maybe even egos are always a good guess. Cogent sent out a press releasing blaming Sprint for the termination.

The Internet has always had holes and strange partitions (e.g. see Dark and Murky Internet Address Space). The Sprint – Cogent dispute is just one more in a decade long line of business and policy issues disrupting Internet connectivity.

In the unregulated ISP interconnect industry, peering is a lot like trick or treating. Sometimes the competitive industry drives down prices and gives customers a treat. But today some Sprint and Cogent customers definitely got tricked.

P2P, Transparency and Fingerpointing…

By: Danny McPherson -

A few months back when I was reading a sample of the feedback [enter 07-52] to the FCC regarding their “Comment Sought On Petition For Rulemaking To Establish Rules Governing Network Management Practices By Broadband Network Operators” solicitation it quickly became obvious that most of the folks that were complaining had little clue what they were talking about, and that every network performance and reachability issue ever experienced by the 35k+ respondents seemed to hastily be attributed to providers unjustly mucking with P2P and other Internet traffic. Of course, this generated more negative PR for the providers involved, and certainly increased call center volumes, which isn’t a desirable thing, but that’s not my point.

A couple weeks back a well-respected security and network researcher, Steven Bellovin, quickly made accusations that problems he was experiencing were likely the result of his provider attempting to manage P2P traffic. Today he redacted his comments when his broadband provider supplied a reason for outage (RFO), as provided in the pointer above. It turns out that the problems he was experiencing were the result of other issues in the network, and had nothing to do with the management of P2P traffic. If Bellovin can make such a misplaced presumption, anyone can.

One of the reasons the Internet has been so successful is because of open, any-to-any connectivity it provides. However, more and more, The End-to-End Principle is violated, either in network architectures, or within the network protocols themselves. Firewalls, NATs, middleboxes, things that synthesize DNS responses, etc.., all compromise end-to-end transparency and add complexity to the network. Application of Occam’s razor tends to immediately cast blame towards these shiny new boxes, at least from an end-user perspective, where little other information is available.

However, practically speaking, given the array of interests contending for Internet resources today (e.g., political, security, individual, commercial, etc..), much of the openness that traditionally existed simply no longer can, and this molestation of transparency is a necessary evil, that with ever-evolving security threats, IPv6 emergence, and more critical services convergence onto Internet infrastructure, is only going to get worse.