Start-up FastSoft is shipping an appliance for speeding up IP WAN links that requires customers to install just one box per connection rather than two, which is the more standard approach.

With its newly announced Aria appliances, the company says it can reduce file transfer times significantly through its use of FastTCP technology. For instance, the company says a 6MB file that took 16 minutes to transfer over a standard TCP connection took only 30 seconds using FastTCP.

FastTCP is technology developed at California Institute of Technology about four years ago to deal with a fundamental problem with the TCP protocol, which requires an acknowledgement that each packet sent has been received before sending the next. If the acknowledgement arrives too slowly, the sending machine significantly throttles back its transmission rate, often resulting in data transfers that are sent more slowly than the link can actually support.

Click to see: FastSoft profile

FastTCP uses algorithms that measure the round-trip time it takes from when a packet is sent until its acknowledgement is received. It uses that information to deduce the maximum sending rate that the link can support. It then adjusts the sending rate accordingly. FastTCP interoperates with normal TCP.

Other vendors, including Blue Coat Systems, Expand Networks, Juniper Networks and Riverbed Technology place a box at both ends of WAN connections and use multiple methods to speed up traffic. They include TCP optimization, which similarly addresses the same problems that FastTCP deals with.

But they also include optimized handling of specific application protocols and various forms of caching so that less data is sent across the WAN. These techniques require matched pairs of appliances, one at each end of the connection.

These vendors also claim similar or greater overall performance improvements compared with FastSoft. Performance of all their products, as well as FastSoft’s, depends on the quality of the connection, delay, packet loss and the mix of traffic crossing the connection. As a result, individual performance varies greatly.

FastSoft’s Aria devices are suited for sites where many scattered devices connect to a single server or set of servers at a central location to download large files. There is no opportunity in these cases for a second device at the other end to support caching and protocol optimization.