Transporter sends equations in place of data
By Craig Matsumoto
EE Times
December 13, 2001 (9:19 a.m. EST)
SAN MATEO, Calif. — Startup Digital Fountain Inc. released technology on Monday (Dec. 10) that it says will speed up file transfers significantly, particularly for applications such as data backup.
By translating a packet stream into mathematical elements, the company eliminates the back-and-forth transactions that confirm whether data has reached its destination. In the Digital Fountain approach, the receiving end waits until it has received a certain number of packets, then signals the transmitting side to stop sending. The operation doesn't require a network processor, but relies instead on the computational power of standard PC processors.
The quirk is that none of the data is ever transmitted; the receiving end creates its own copy of a file based on a complete set of mathematical equations. The box announced by Digital Fountain this week is named the Transporter Fountain after the person-moving transporter in the Star Trek television series, which operated on a similar principle, according to some episodes of the series.
"We send recipes, not pieces of content," said Clifford Meltzer, chief executive of Digital Fountain. "Once you get enough [of the packets] coming in, Spock appears. If you get 98 percent of the packets, you get nothing."
Transporter Fountain was created to handle large, long-distance file transfers that are normally conducted via the File Transfer Protocol (FTP), using the Transport Control Protocol (TCP) to manage the session. But FTP requires packets to arrive in sequence, and TCP requires a receiving end to acknowledge every packet that arrives, so that dropped packets can be resent.
The result is a dialogue that can slow down a session, particularly if files are sent across the Internet. Meltzer recalled a job where the client had a 32-Mbit/second connection available but was getting a throughput of 0.5 Mbits/s. "It wasn't a question of mere bandwidth. They had too much turnaround," he said.
Among the possible applications for Transporter Fountain is the delivery of taped-out semiconductor designs between a foundry and a chip vendor. These files routinely are mailed on tape rather than transmitted electronically. "FedEx is a hell of a lot more reliable than FTP when you're running 20 Mbytes," said Charlie Oppenheimer, vice president of marketing at Digital Fountain.
Go Speed Racer
Digital Fountain proposes to speed up FTP transfer by eliminating most of the back-and-forth communication between sender and receiver. The intent is to alter the data transfer so that the receiving end only cares how many packets it has received, regardless of their sequence.
The Transporter Fountain uses proprietary algorithms to create a mathematical model of the data being sent. Meltzer likened it to a set of linear equations, where a problem involving "n" variables can be described by solving a combination of "n" equations of the right type.
In this case, the Transporter Fountain creates not equations but hundreds of millions of "symbols" which can be used to reconstruct the data. The sending side transmits these symbols until the box on the receiving end confirms that it's collected enough symbols. The receiving box then performs an XOR operation on the symbols to derive the original data. The translation is straightforward enough to be handled by a Pentium III processor, Oppenheimer said.
The arrangement saves time because neither side cares if a packet gets dropped, thus eliminating the dialogue required by TCP and FTP.
The Transporter Fountain sits alongside a switch or router, and one Transporter Fountain is needed at the sending and receiving ends of a connection. Prices will range between $70,000 and $150,000.
Two versions of the system are due to ship later this month. The Transporter Fountain 1000 box measures one rack unit high and can handle connections as fast as 10 Mbits/s. The Transporter Fountain 3000 box handles three rack units and data rates up to 70 Mbits/s.
planetanalog.com |
