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Executive Editor

Peribit aims to reduce network latency with PFA

Sep 15, 20033 mins

Peribit Networks is adding technology to its compression platform that enables it to cram even more data over expensive WAN links – reducing the time to send a block of data by an additional half.

Called Packet Flow Acceleration (PFA), the technology helps reduce delay caused by the normal functioning of TCP, thereby increasing the rate at which applications can send data. This acceleration is piled on top of Peribit’s existing technology that reduces the number of bytes in a data transfer.

The company claims its compression technology reduces certain types of traffic by as much as 75% or 80%. Peribit also supports quality-of-service settings that enable customers to give key applications priority, making them perform better.

Adding PFA to the mix reduces TCP-induced delay and can further improve throughput by more than 100%. In an example, the company claims a compressed body of data that takes 9 minutes to cross a WAN connection can cross the same connection in 4 minutes with PFA.

PFA reduces delay by adjusting the TCP receive window to the maximum that the available bandwidth can support. If left on its own, TCP would interpret latency on the WAN link as slow acknowledgements and keep the window smaller than it needs to be.

Over links with significant delay because of distance, TCP stretches out the delay even more as it waits for ACK packets. “If you can get that ACK accelerated, it can feel like you are on a LAN,” says Chip Greel, network architect for optical equipment maker Finisar in Sunnyvale, Calif.

At least that’s what he hopes. Finisar already uses Peribit gear and is going to beta test the new software. Greel hopes it will reduce delay enough that Finisar can support Oracle applications to four Pacific Rim branch offices from Sunnyvale over the company WAN. “It makes you reconsider placing a second instance of Oracle across the pond,” he says.

PFA is a feature that Peribit’s primary competitor, Expand Networks, does not have. PFA will be available next month.

Peribit is also introducing a new appliance called Sequence Reducer (SR) 80 that has both copper and fiber Gigabit Ethernet ports and can process packets for the WAN at up to 45M bit/sec. The device ranges in price from $22,500 to $73,500 depending on the type of ports and the throughput of the box. SR 80 also supports up to 320 separate endpoints for large networks. It will be available in November.