Slightly old news, but it looks like Cogent depeered ESnet last week:
http://www.es.net/news-and-publications/esnet-news/2011/important-status-announcement-regarding-cogent-connectivity/
Current traceroutes indicate that ESnet is reaching Cogent via 6939_1299.In other news, automatically dropping interconnects at around the time of your HQ's close of business while your peering co-ordinator is on vacation seems to be the new gold standard.
Nick
