WASHINGTON, D.C., July 6, 2005 - Cogent Communications Group, Inc. (AMEX: COI), a leading Tier 1 Internet service provider, announced today that Ovum-RHK has reported Cogent as the largest provider of Ethernet services in United States based on the number of ports in service. According to RHK's research, Cogent ranked as the third largest revenue producer from Ethernet services as well.

Furthermore, Ovum-RHK's Brian Van Steen stated in the report, "In the United States, Cogent is the leading service provider from a port perspective, but its focus on price leadership for 100 Mbps Ethernet-based Internet access ($1,000 per month [for corporate customers]) means that it is not the revenue leader."

"Cogent's network design and focus on IP services enable Cogent to operate at substantially less cost than traditional networks that carry a combination of voice and data. Rather than advertise a discount to the market, Cogent passes a majority of the savings onto customers in the form of our very affordable everyday pricing," said Dave Schaeffer, CEO Cogent Communications. "Cogent recently conducted a survey of 4,000 U.S. customers, and we found the number one thing our customers value most is our pricing, followed very closely by the quality of service we provide. "

In terms of ports in service, Cogent was listed ahead of other Ethernet providers including AT&T, BellSouth, MCI, SBC, Time Warner Telecom, Verizon, and XO.

About Cogent Communications

Cogent Communications (AMEX: COI) is a next generation, multinational, Tier 1 ISP. Its facilities based, all-optical network delivers ultra-high speed Internet access and transport services to businesses and service providers in major metropolitan areas. Cogent offers services across its 30,600-mile IP network spanning 12 countries in North America and Europe.

Cogent is one of the fastest growing ISPs in the industry due to the combination of technology, IP network architecture and a unique business model that provides customers with unprecedented value.

In addition to On-Net Internet access service, Cogent also offers dedicated Off-Net (T1, T3) Internet service, collocation services in 30 data centers in North America and Europe, and Layer 2 Point-to-Point services in every On-Net market.

Cogent Communications is headquartered at 1015 31st Street, NW, Washington, D.C. 20007. For more information, visit www.cogentco.com. Cogent Communications can be reached in the United States at (202) 295-4200 or via email at Diese E-Mail-Adresse ist vor Spambots geschützt! Zur Anzeige muss JavaScript eingeschaltet sein!.

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Information in this release may involve expectations, beliefs, plans, intentions or strategies regarding the future. These forward-looking statements involve risks and uncertainties. All forward-looking statements included in this release are based upon information available to Cogent Communications Group, Inc. as of the date of the release, and we assume no obligation to update any such forward-looking statement. The statements in this release are not guarantees of future performance and actual results could differ materially from our current expectations. Numerous factors could cause or contribute to such differences. Some of the factors and risks associated with our business are discussed in Cogent's registration statements filed with the Securities and Exchange Commission and in its other reports filed from time to time with the SEC.

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