HERNDON, VA and SUNNYVALE, CA--(Marketwire - June 12, 2008) - XO Communications (OTCBB: XOHO) and Infinera (NASDAQ: INFN) will team up to deliver the first demonstration of 100 Gigabit Ethernet traffic in production-ready form over a live network. The demonstration, at Infinera's booth number SU5607 at NXTcomm08 from June 17th through the 19th in Las Vegas, will show how 100 GbE services can be delivered today over existing network infrastructures.

The demonstration will consist of an Ixia proof-of-concept 100 GbE test set generating and handing off a pre-standard IEEE 802.3ba 100 GbE signal to a 100 GbE interface on the Infinera DTN DWDM transport system. The 100 GbE signal will then be switched and transported by the Infinera DTN system from the show floor through XO Communications' long-haul DWDM network to Los Angeles. The 100GbE signal will then be looped and transported back to the Infinera booth in Las Vegas, where performance metrics will be monitored and viewable on the Ixia XM2 chassis.

100 GbE Next Major Step for Telecom Networks

Ethernet has emerged as the protocol of choice for many next-generation telecom networks for its superior economics and widespread use in local area networks. With aggressive growth in Internet traffic worldwide, networks and networking equipment need to scale beyond 10 Gigabit Ethernet and the IEEE 802.3ba Task Force is working to develop 100 Gigabit Ethernet as the next important standard for telecom networks. Many industry participants believe that 100 Gigabit Ethernet interfaces and services will enable simplified, cost-effective connectivity for telecom customers, including Internet content providers, Internet service providers, telecom companies, enterprises, and other large users of bandwidth. This demonstration shows that progress has been made on several important fronts and the technology exists today to deliver 100 GbE services on existing networks.

XO Communications supports customers on its nationwide network today with services including 10 Gigabit/second (Gb/s) wavelengths and 10 GbE. Demonstrating the power and scalability of XO's advanced optical network, XO Communications has pioneered a new rapid service delivery model with its "10 Gigs in 10 Days" guarantee, offering customers the ability to have 10 Gb network services provisioned in 10 business days. XO Communications is committed to bringing 100 GbE services to market as soon as the technology reaches a state where it is deployable and economic. This demonstration shows that XO is focused on playing an active role in the development of this important technology.

"Not everything that happens in Vegas stays in Vegas. This pioneering demonstration of 100 GbE traffic will leave Vegas and visit Los Angeles over the XO network, for just a fraction of a second, before returning to Vegas, for the enjoyment and education of NXTcomm visitors," said Randy Nicklas, chief technology officer at XO Communications. "XO is determined to be a leader in developing new capabilities and optical services to meet our customers' growing need for bandwidth."

Infinera's Bandwidth Virtualization Enables 100 GbE Today

In the NXTcomm08 demonstration, the 100 GbE signal is received from the Ixia test set and striped across ten 10 Gb/s wavelengths using Infinera's Digital Virtual Concatenation protocol, and then transmitted over the long-haul network by Infinera's Photonic Integrated Circuit (PIC)-enabled DTN platform, before being reassembled by the Infinera system at the other end. The Tributary Adapter Module (TAM) in this demonstration, which fits into today's Infinera 100 Gb/s Digital Line Module (DLM), is in a commercially suitable form-factor and ready for development into a commercial product.

100 GbE services will be supported by Infinera's new 160-channel ILS2 line system unveiled last week, which delivers 1.6 Tb/s of optical capacity with Infinera's market-leading 100 Gb/s DTN line cards. With the future introduction of Infinera's next-generation line cards, the ILS2 line system will be scalable up to 8 Tb/s of capacity. In all cases, Infinera's Bandwidth Virtualization™ ensures that 100 GbE services will be delivered seamlessly, independent of whether the underlying optical infrastructure is based on 10G, 40G, or 100G channels, or a mix-and-match combination thereof.

Bandwidth Virtualization facilitates the decoupling of bandwidth services such as 100GbE from the underlying optical transport infrastructure, enabling improved flexibility, improved wavelength utilization, and rapid service activation without optical re-engineering of the line system. The optical capacity is available to be deployed in any rate from 1 Gb/s to 100 Gb/s and in a variety of protocols including Ethernet, SONET/SDH, or wavelengths. An Infinera network helps customers consolidate any mix of 1 Gb/s, 2.5 Gb/s, 10 Gb/s, 40 Gb/s, and future 100 Gb/s services simultaneously over the same network infrastructure -- with no additional investment or upgrade necessary for the line system.

"Infinera is a leader in the introduction of 100 GbE technology and services," said Infinera Chief Technology Officer Drew Perkins. "Our Bandwidth Virtualization architecture makes it possible to deliver 100 GbE services over today's networks and the scalability and intelligence of the Infinera platform makes it the best suited to deliver these new high-capacity services. We are also actively involved in the standards bodies and working to reach agreement on standards that can foster the development of practical, cost-effective, and widely deployable 100 GbE solutions."

NXTcomm08 takes place at the Las Vegas Convention Center in Las Vegas, Nevada. Visitors to the show are invited to stop by the Infinera booth to see this demonstration or contact their representatives to arrange an appointment. Press and analysts can arrange a meeting via the contacts listed below.

About XO Communications

XO Communications, a subsidiary of XO Holdings, Inc. (OTCBB: XOHO), is a leading provider of 21st century communications services for businesses and communications services providers, including 50 percent of the Fortune 500 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 www.xo.com.

About Infinera

Infinera provides Digital Optical Networking systems to telecommunications carriers worldwide. Infinera's systems are unique in their use of a breakthrough semiconductor technology: the photonic integrated circuit (PIC). Infinera's systems and PIC technology are designed to provide optical networks with simpler and more flexible engineering and operations, faster time-to-service, and the ability to rapidly deliver differentiated services without reengineering their optical infrastructure. For more information, please visit www.infinera.com.

This press release contains certain forward-looking statements based on current expectations, forecasts and assumptions that involve risks and uncertainties. These statements are based on information available to Infinera as of the date hereof; and actual results could differ materially from those stated or implied, due to risks and uncertainties. Forward-looking statements include statements regarding Infinera's expectations, beliefs, intentions or strategies regarding the future, such as the benefits and capabilities of our products and the Digital Optical Network's architecture, that Infinera networks help customers consolidate any mix of 1 Gb/s, 2.5 Gb/s, 10 Gb/s, 40 Gb/s, and future 100 Gb/s services simultaneously over the same network infrastructure -- with no additional investment or upgrade necessary for the line system, that the scalability and intelligence of the Infinera platform makes it the best suited to deliver these new high-capacity services, that the ILS2 line system will deliver 8 Tb/s of capacity, that Bandwidth Virtualization ensures that 100 GbE services will be delivered seamlesslyand that we will work to reach agreement on standards that can foster the development of practical, cost-effective, and widely deployable 100 GbE solutions. Such forward-looking statements can be identified by forward-looking words such as "anticipated," "believed," "could," "estimate," "expect," "intend," "may," "should," "will," and "would" or similar words. The risks and uncertainties that could cause our results to differ materially from those expressed or implied by such forward-looking statements include aggressive business tactics by our competitors, our dependence on a single product, our ability to protect our intellectual property, claims by others that we infringe their intellectual property, our manufacturing process is very complex, product performance problems we may encounter, our dependence on sole or limited source suppliers, our ability to respond to rapid technological changes, our ability to maintain effective internal controls, the ability of our contract manufacturers to perform as we expect, a new technology being developed that replaces the PIC as the dominant technology in optical networks, general political, economic and market conditions and events, including war, conflict or acts of terrorism; and other risks and uncertainties described more fully in our annual report on Form 10-K filed with the Securities and Exchange Commission on February 19, 2008, our public announcements and other documents filed with or furnished to the Securities and Exchange Commission. These statements are based on information available to us as of the date hereof and we disclaim any obligation to update the forward-looking statements included in this press release, whether as a result of new information, future events or otherwise.

Contact Information: For further information: XO Communications: Media: Chad Couser XO Communications Tel: +1-703-547-2746 chad.couser@xo.com Infinera: Media: Jeff Ferry Tel. +1-408-572-5213 jferry@infinera.com Infinera: Investors: Bob Blair Tel. +1-408-716-4879 bblair@infinera.com