Latency, In order to perform properly in conjunction with traditional terrestrial land based and wired networks satellite data networks must employ specialized hardware to deal with the increased latency caused by the 96,000 mile round-trip over the space segment of the connection. The 96,000 mile round-trip adds extra milliseconds (600 miliseconds) to the transmission of a packet of data. Eliminating latency is done through several TCP acceleration techniques (TCP spoofing).

TCP works by starting a TCP/IP session slowly. Speed builds as the network's capacity to carry traffic is verified by the rate of the acknowledgments. This effect is known as slow-start. Commercial satellite providers overcome the slow start by utilizing TCP spoofing. This technique is done through specialized hardware and software that acknowledges packet transmissions on the ground at the network hub before they are transmitted over the satellite connection. The land based hardware then buffers the packets and transmitts them in an accelerated manner over the satellite link rather than waiting for the initial packet to completly traverse the ground to satellite path.

VPN, Virtual Private Networks have become increasingly important to businesses large and small as they strive to connect remote users with their internal intranets. Because of terrestrial delay, or latency, commercial satellite providers provide VPN services in a modified manner. Since their own internal network and satellite transmissions are DES encoded they are considered secure. With encrypted transmissions the VSAT terminal netwrok termination interface (NTI or satellite modem) must have the processing power to encrypt and decrypt packets while still maintaing broadband throughput. This processing adds cost to the NTIs but it also makes responsive, secure VPNs possible.

Commercial satellite carriers maintain a VPN connection to a customer from their land based network node to the customer's land based network node. This secure VPN traffic is then transported in an encrypted packet over the satellite link to the remote office where the customer's traditional VPN software is used to establish the final connection. In this manner latency is minimized.

Offerings, At CPE Labs we offer commercial solutions from two vendors. The first is our own internal offering backed by SkyVista communications. The second is from VSAT Systems. SkyVista offers an entry level commercial offering to the small business market. They have systems priced at under $1,000 and monthly access charges starting at $69.99 per month. VSAT Systems market to small businesses and entrprise corporations with product plans designed to meet the needs of the client as either a primary access provider or as a backup service provider. VSAT Systems start at $1,500 and monthly access charges around $100.