Cogent Communications is a multinational internet service provider based in the United States. Cogent's primary services consist of Internet access and data transport, offered on fiber optic, IP data-only network, along with colocation in data centers.
Cogent was founded in 1999 at the peak of the industry's growth. In three years, Cogent acquired 13 other carriers, purchasing $14 billion in capital for $60 million, including $4 billion worth of Property, Plant and Equipment.
- September 2001 - Acquires the assets of NetRail
- February 2002 - Acquires Allied Riser
- April 2002 - Acquires Building Access Agreements from OnSite Access
- April 2002 - Acquires Major US Assets of PSINet
- September 2002 - Acquires Major Assets of FiberCity Networks
- February 2003 - Acquires Fiber Network Solutions
- May 2003 - Acquires Assets of Applied Theory
- January 2004 - Acquires LambdaNet France & Spain
- March 2004 - Acquires Fiber Network and Equipment in Germany Out of Former Carrier1 Assets
- September 2004 - Acquires Global Access
- October 2004 - Acquires Aleron Broadband
- December 2004 - Acquires NTT/Verio Dedicated Access Business in U.S.
Cogent has been the subject of numerous peering disputes. On April 28, 2011, Communications Network Services engineer Phil Benchoff noticed that Cogent, Virginia Tech's commodity Internet provider, had depeered with both Google and Hurricane Electric, a major provider of IPv6 transit, causing some IPv6 routes to become available only over Internet2.  On a NANOG mailing list, a HE employee blamed Cogent for refusing to peer.