Backbone Directory: XO Communications

Born of the former Nextlink Communications and Concentric Networks, XO's network now includes over a million miles of fiber nationwide.

by Jeff Goldman [June 8, 2005]

XO Communications was formed in September of 2000 when broadband provider Nextlink Communications acquired Concentric Networks, and was re-branded to reflect a new focus on simple but comprehensive services. Later acquisitions, including the purchase of Allegiance Telecom in April of 2004, have added significantly to XO's portfolio.

The company's backbone network is built around a mesh of OC-192 (10 Gbps) circuits, which connect XO's POPs and data centers. The backbone itself runs completely across XO's own intercity facilities. The company also offers enhanced connectivity by connecting each market to the backbone with dual OC-12c SONET-protected circuits.

XO maintains private peering arrangements in many U.S. metropolitan areas at speeds of up to OC-12, as well as multiple and geographically redundant dedicated connections to other leading Internet backbones. These arrangements are designed to improve efficiency and reduce packet loss by ensuring that customer traffic crosses the XO backbone and the peering partner's backbone only.

Dedicated Internet access is available via POPs in more than 60 markets, as well as DSL connections in 42 markets—all of which are connected to the closest OC-192 IP core node. Dual uplinks are provided from each metro market to the closest intercity core node at speeds from OC-3c (155 Mbps) to OC-48c (2.4 Gbps). XO's metro area networks include 1.16 million metro fiber miles in 40 major U.S. cities.

XO also offers fixed wireless access at a frequency of 27 GHz - 32 GHz, which covers 95 percent of the population in the top 30 cities across the U.S.

Key network info:

• 2,300+ on-network buildings
• Five data centers as well as a 24/7 network operations center
• 300-plus DSL access points
• 100+ Tier One peering POPs offering direct access to 85 percent of Internet traffic
• OC-192 backbone
• Total fiber: approximately 1,158,000 miles
• 34 Nortel DMS-500 switches for local and long distance voice
• Sonus Networks softswitches for handling next-generation traffic
• Fixed wireless licenses covering 95 percent of top U.S. business markets