The main problem with the TCP protocol, which was designed before wireless connections to the Internet were commonplace, is that it doesn't know the difference between packets of data that are lost because of network congestion and those that are lost because of a weak wireless signal. TCP automatically throttles the speed of data transfer when it sees dropped packets, so that congestion doesn't overwhelm the network. That's fine when packets are lost because of congestion, but when the problem is a weak signal, it causes an unnecessary drop in transfer speeds that can bring downloads and uploads to a crawl.
Fasp-AIR achieves faster speeds than TCP but doesn't result in any dropped packets, making it suitable for transferring data that must arrive complete and intact. "The drop-off in performance we see with fasp-AIR is almost linear," says Aspera CEO Michelle Munson. "So a 10 percent loss in the available bandwidth means we're still getting transfer rates that are 90 percent of what's specified."
Fasp-AIR requires that both the client and the server are running software developed by Aspera. In the future, Aspera hopes that developers will incorporate fasp-AIR into their applications directly. Aspera licensees currently include Amazon and several other large Internet companies.
Other New Approaches
Crowcroft's own solution to this problem, first implemented with Vodafone almost a decade ago, involved configuring the proxies that connected the wireless network to the wired data and voice backbones so that they could monitor all TCP traffic. This allowed the proxy to tell individual devices when they were in a "lossy" part of the wireless coverage area. "It's not a general solution," says Crowcroft. "If [Aspera] has a general solution, good luck to them."
Another wireless network company, the San Francisco-based Meraki, takes a similar approach, mapping a network's usage and lossiness and then using that information to optimize it at the level of individual wireless routers