Satellite Internet how broadband satellite Internet acceleration works 

Satellite Internet:
How Acceleration Works

In order to perform properly in conjunction with traditional terrestrial networks (Internet, intranet), satellite data networks must employ special techniques to deal with the increased latency caused by the 96,000 mile round-trip over the space segment of the connection.

The increased latency is caused by the extra milliseconds required for data to travel this distance. While not related directly to speed, latency can cause a severe performance problem over satellite links if not handled properly. VSAT Systems deasl with latency through the use of the most advanced TCP/IP acceleration technology available.

Some Background
TCP/IP is the “language” of the Internet. It works by sending packets of data, and then waiting for acknowledgments of receipt. These acknowledgments signal the sender to transmit more data. When acknowledgments return slowly, TCP then slows the speed at which data is being sent in order to avoid overloading a network that it assumes is already congested.

TCP works by starting a TCP/IP session slowly. Speed builds as the networks capacity to carry traffic is verified by the rate of the acknowledgments. This effect is known as slow-start.

Since TCP was designed for terrestrial networks that have less latency than a satellite network, the longer satellite latency (600ms range) will cause TCP to expect an acknowledgment before the round trip to the remote site can be completed.

Because TCP was originally designed for low-latency terrestrial networks, it does not understand that a satellite is involved and operates as if the satellite latency was caused by congestion. If uncorrected, this effect causes all packets over a satellite network to be sent at the slow-start rate.

In all current-generation satellite data networks TCP/IP acceleration (TCP spoofing) compensates for the space-link transit time. TCP spoofing is accomplished by special equipment at the carrier’s main satellite hub site.

This equipment appears to TCP as if it were the remote location, while acting as a relay or forwarder for data packets going to and from the remote satellite location. When the spoofing equipment receives Internet traffic destined for a remote satellite location, it acknowledges receipt of the packet immediately on behalf of the remote site so that more data packets will follow immediately.

In this manner, the latency is “hidden” because the acknowledgments are returned rapidly. As a result, TCP moves out of slow-start mode quickly and builds to the highest possible speed.

The VSAT Systems acceleration equipment also watches for real acknowledgements coming back from the remote site and suppresses them. If the acknowledgement is not received from the remote site, the system automatically re-sends the packet from its buffer. Thus, satellite-connected sites communicate seamlessly with servers on the terrestrial Internet.

The Satellite VPN Issue
VSAT Systems satellite Internet platforms are friendly with most VPN solutions. Customers can use their current VPN solution with our equipment but if you are looking for a 100% compatible VPN solution we can offer our lab and field tested solutions. 

The VSAT Systems Accelerated VPN Option
This solution is not truly a VPN, but a hybrid VPN and PN (Private Network). It does not have the VPN-over-satellite performance limitations of it’s competitors. This is because VSAT Systems creates for you, a 3DES encrypted private satellite network and then securely connects your 3DES private satellite network directly to your headquarters network eliminating the need to use additional VPN across the space segment.

In the VSAT Systems private network model, all data is secured across the space link by 3DES encryption and is therefore secure with or without added VPN technology.

VSAT Systems connects the secure traffic between your private satellite network and your companies headquarters network across a variety of customer-selected options including point-to-point T-1, Frame Relay PVC or VPN across the Internet. Since the Internet method is by far the least costly, it is the most popular.

This technology approach completely avoids the performance problems of VPN-over-satellite because there is no traditional VPN being used across the satellite portion of the connection.