For release: May 6, 2005

Avtec Systems SCPS Communications Gateway Improves Bandwidth and Data Throughput Over Lossy, High-Latency Links

CHANTILLY, VA -- May 6, 2005 -- Avtec Systems, Inc. announced today the release of an enhanced SCPS (Space Communications Protocol Standards) Communications Gateway. The Gateway extends TCP/IP to maximize network throughput and link utilization, successfully addressing the challenges of non-optimal data links (such as lossy, high-latency, asymmetric bandwidth environments typical of space and terrestrial/tactical RF communications). The SCPS Gateway also provides a reliable, standards based Performance Enhancing Proxy (PEP) to improve TCP performance.  By dramatically improving link bandwidth utilization and data throughput over high bandwidth delay, high bit error links, the SCPS Communications Gateway assures reliable network applications over diverse networks.

PROBLEMS WITH DATA TRANSMISSION VIA "CHALLENGED" LINKS
While standard TCP/IP implementations perform extremely well in terrestrial networks, the protocol still has performance limitations in noisy, high latency environments. In a standard TCP session, whenever a packet is lost, it is assumed an indication of network congestion.  The proper response for a terrestrial TCP session is to cut the rate of transmission of segments into the network.  However, in a wireless environment, packet loss is not automatically an indication of congestion and so the sender is needlessly reducing its transmission rate.  Making matters worse, when a packet loss occurs and the TCP session re-invokes slow-start, it takes much longer to recover from this phase due to the high latency of ACK (Acknowledgement Code) packets (i.e., high round trip times).

HOW DOES SCPS MAKE THINGS BETTER?
Based on the CCSDS (Consultative Committee for Space Data Systems) protocols, Avtec?s SCPS Communications Gateway helps overcome these performance limitations of TCP/IP over satellite and terrestrial RF links.  It lets users easily achieve better bandwidth utilization, faster retransmission, and dramatically higher throughput with a turnkey solution, completely transparent to IP applications and end users.

EASE OF USE
To protect customers' legacy systems investments, Avtec's SCPS Communications Gateway is a turnkey, standards-based network device that integrates seamlessly into the network.  The Gateway can be inserted into the network in "transparent" operating mode, or can function as a router.  In "transparent" mode, it acts as a bridge between TCP and SCPS-TP network segments at the Ethernet level and is essentially invisible to the local IP network.  As a "router", the Gateway performs this bridging function while operating on the local network as an IP router implementing the BGP (Border Gateway Protocol).

BREAKTHROUGH PERFORMANCE
The Avtec SCPS Gateway supports link data rates up to 155 Mbps. Over a typical satellite link, the SCPS Gateway increases throughput by 2 1/2 to 3 times, while performance gains of up to 100 times standard TCP rates are not uncommon over low-quality links.

To download a complimentary copy of Avtec?s SCPS Communications Gateway background and overview article, please visit http://www.avtec.com/scps.

ABOUT AVTEC SYSTEMS
Data, unbounded: Avtec is a leading provider of advanced systems for satellite data communications. Our products power fast, reliable data flow across boundaries and through the most challenging environments. Off-the-shelf solutions include high-speed satellite receivers, communications gateways, protocol processors and translators, network-edge devices and test systems.

Engineering for tomorrow: Avtec's services organization provides innovative custom hardware, software, algorithms, simulations and analyses in order to solve our customers' toughest real-world engineering problems. For the past two decades, Avtec has supported military, intelligence, government and private-sector aerospace programs through the entire engineering lifecycle, beginning at concept development and extending through mission flyout.

PRESS CONTACT
Carol Conrad
Avtec Systems, Inc.
14432 Albemarle Point Place
Chantilly, VA 20151
Toll Free US:  877-AVTEC-05
Tel:  703-488-2500   
Fax:  703-488-2555
Email: press@avtec.com