XO COMMUNICATIONS TO INCREASE CORE NETWORK CAPACITY.

In a continuing effort to meet increased demand for network bandwidth from enterprises, service providers and telecommunications companies, XO Communications, Reston, Va., has announced a significant increase in the capacity of its core network by 200 percent. XO will deploy an additional 800 Gigbits (Gbps) of capacity on major coast-to- coast routes across its nationwide 18,000 route-mile optical network, augmenting a capacity expansion XO completed last year which delivered 400 Gbps of capacity across its network.

In a separate announcement today, XO Communications has also extended the availability of its successful 3 Guarantee Program, which was initiated earlier this year to offer carriers, cable companies, content providers, large enterprises and wireless companies increased incentives to leverage XO's suite of inter-city and metro network transport solutions, including Ethernet, IP Transit, and Wavelength services. The XO program offers large enterprise and carrier customers the industry's most competitive rates and guarantees for high-capacity network services delivered over XO's extensive nationwide inter-city and metro networks.

As a result of the explosion in customer driven demand for bandwidth- hungry applications and services such as online video streaming, rich multi- media content, HD video, VoIP, and higher-speed broadband offerings, service providers such as cable companies, content providers and telecommunications companies are facing increased demands on their networks for more capacity. The new capacity XO will deploy is part of the company's aggressive multi- million dollar network investment and marketing initiatives begun last year to stay ahead of the growing demand for XO's inter-city network transport services and position the company as the new, more agile provider of network services for large enterprise and service provider customers.

For the new capacity upgrade, XO will light two new fiber strands on its nationwide fiber network, adding 800 Gbps of capacity in core XO network nodes which will deliver an additional 80 10-Gbps channels on major coast-to-coast XO network routes. XO Communications has contracted with Infinera Corporation (NASDAQ:INFN) to implement the new capacity upgrade using the Infinera DTN system, which XO implemented last year with the initial expansion of its network.

"Because of continuing customer demand and the success we have had in the market to date, XO is taking additional actions to stay ahead of demand for high-capacity long haul services from enterprise and carrier customers," said Ernie Ortega, president of XO Carrier Services. "Our network investments, industry-leading optical technology and sales initiatives have enabled XO to become the new, more agile provider of long haul and high-capacity network services for large enterprises and carrier customers."

A New, More Agile Provider of High-Capacity Network Services

Following the expansion of the XO network last year and continuing with the new capacity upgrade announced today, XO is establishing itself as the new, more agile provider of high-capacity network services for large enterprises and service providers, including major cable companies, content providers, telecommunications carriers and wireless companies. Through the flexibility, scalability and advanced optical technology deployed in the XO network, XO is able to provision services faster and provide a broad range of higher-speed network transport services. As a result of its network investments and initiatives, XO has been able to achieve:

-- A 514% increase in sales orders for high-capacity inter-city network transport services from Q1 2006 to Q1 2007; -- New wins with major domestic and international telecommunications carriers, online gaming, content and Internet-centric companies including China Netcom USA, GameRail, NTT America and PCCW Global; and -- Industry recognition for XO's advanced optical network by winning the 2007 NXTcomm Eos award for Best Backbone/Core Network, two U.S. Wholesale Excellence Awards from ATLANTIC-ACM for the quality and value of its data services and quality of its sales representatives, and the 2006 Metro Carrier Excellence Award from ATLANTIC-ACM for best wholesale voice over IP (VoIP) service provider.

The XO nationwide inter-city network connects 75 major metropolitan markets across the United States. In addition to its extensive inter-city network, XO owns 9,100 route miles, consisting of nearly 1 million fiber miles of metro fiber networks in major markets across the United States. With its extensive nationwide and metro network assets, XO is uniquely positioned to offer network transport services that provide door-to-door delivery of customer network traffic. In addition, the deployment of industry-leading digital optical technology across its nationwide inter-city network enables XO to provision services faster and provide a broad range of higher-speed network transport services, including:

-- Ethernet services from GigE to 10 Gbps speeds -- IP Transit services from OC-3 to OC-192 speeds -- Private Line services from OC-3 to OC-192 speeds -- Wavelength services at 2.5 Gbps and 10 Gbps speeds

For more information about the XO network, go to http://www.xo.com/about/network. For more information about the campaign or to contact an XO sales representative, call 800/474-1763.

About XO Communications

XO Communications, a subsidiary of XO Holdings, Inc. (BULLETIN BOARD: XOHO.OB) , is a leading provider of 21st century communications services for businesses and communications services providers, including 40 percent of the Fortune 1000 and leading cable companies, carriers, content providers, and mobile operators. Utilizing its unique and powerful nationwide IP network and extensive local metro networks and broadband wireless facilities, XO offers customers a broad range of managed voice, data and IP services in 75 metropolitan markets across the United States.

For more information, visit http://www.xo.com or call 703/547-2746.