April 2008
Buggy Voting Systems in New Jersey (4 April 2008)
An Outage from Managing P2P Traffic? (6 April 2008)
Ships Impounded in Cable Cut (8 April 2008)
Comcast Outage: Not P2P-Related (18 April 2008)
PayPal is Wrong About Unsafe Browsers (19 April 2008)
New Jersey Supreme Court Protects Internet Users' Privacy (22 April 2008)
The Fate of Old Hardcopy Journals (27 April 2008)

Comcast Outage: Not P2P-Related

18 April 2008

A couple of weeks ago, I posted a note speculating that the outage I experienced was due to a problem in the gear Comcast was using to manage peer-to-peer traffic. After correspondence with some of their network engineers, I’m happy to say that I was wrong. Here’s the short form of the explanation:

We encountered a memory limitation on a handful of our core routers in the PA-NJ area triggered by an external routing event. The switching mode of the routers changed in that situation. In this new mode, subscriber traffic was subjected to an internal infrastructure security policy that permitted ping and traceroute but denied TCP traffic. This caused the discrepancy of website reachability based on subscriber location and the idiosyncratic ping and traceroute behavior.
So — I apologize to Comcast, and I’m quite happy with their willingness to discuss this with me further.