PORTLAND, Ore. Network congestion, like vehicular traffic jams, is getting worse. No matter how fat the pipe, the antiquated Transmission Control Protocol (TCP) never fully utilizes the available bandwidth.
Developers have tried for several years to improve TCP performance and its Layer 4 counterpart, the User Datagram Protocol, using revised protocols and hardware accelerators. Members of the Internet Engineering Task Force have promoted experimental TCP alternatives. None have gained wide acceptance.
Likewise, silicon vendors have devised in-line accelerators, collectively known as TCP Offload Engines, or TOEs, but the standalone TOE chip is being replaced by a TOE accelerator block that resides in an Ethernet switch or network processor.
Another solution would be to redesign TCP to take advantage of smart network routers, but that would make obsolete existing hardware and require users at both ends of a data transmission to buy new equipment.
Now FastSoft Inc. (Monrovia , Calif.) claims to have redesigned network protocolsdubbed Fast TCPso networks make maximum use of available bandwidth with existing routers and without new equipment.
"TCP was designed over 30 years ago, and it makes implicit assumptions about how networks behave which were true when back then but are increasingly causing performance problems today," said Cheng Jin, FastSoft's founder and vice president for engineering. "What we have done is redesign TCP to fit today's larger networks."
TCP works by breaking up data files into packets that are reassembled by a receiving computer into the original file. As each packet is received, an acknowledgment is sent to the sender. If no acknowledgment is sent for a packet, the sender resends it until an acknowledgment is received for all packets. That approach forces repeated retransmission of many packets.
"There are a lot of packet losses in the network, which gets worse the further your data transmission has to travel," said Jin. "With our algorithm, you get to utilize all the bandwidth available to you, which you can never achieve using ordinary TCP."
FastSoft's patented technology tracks the delay between packet transmission times and the time it takes to receive acknowledgment. It then fine tunes packet transmission rates to match network congestion, avoiding a technique called packet oscillation. While maintaining a steady data transmission pace, which increases throughput, packets need not be retransmitted, thereby doubling throughput, FastSoft claims.
"One of our beta sites, Honda, used to take 16 minutes to transmit a large CAD file, but now it only takes them 30 seconds," said FastSoft vice president Dan Henderson.
Fast TCP uses two time scales to optimize data transmission speeds: A slow time scale meters transmission speeds to match the delay between packet transmission and acknowledgment; a second "burstiness" control algorithm works at a shorter time scale to adjust the number of packets sent in response to network congestion.
FastSoft said it will begin shipping its Aria 1000 Fast TCP appliance in June, a single-board server that, when installed between a LAN switch and a firewall, accelerates date transmission by as many as 32 times, FastSoft claims.
Loring Wirbel contributed to this report.