Network coding: Networking's next revolution?

Network World - Some of high tech's biggest names -- Microsoft Corp., Hewlett-Packard Co. and Intel Corp. among them -- are starting to embrace a technology called network coding in an effort to boost throughput, scalability and efficiency of everything from content distribution to wireless networks.

Network coding, largely shrouded in university and vendor labs since it was proposed seven years ago by a handful of researchers, is essentially an algorithm that proponents say can potentially more than double network throughput while also improving reliability and resistance to attacks. According to network coding's most ardent supporters, the technology could spark networking's next revolution, while others said network coding is more likely to quietly infiltrate network architectures based on existing routing schemes.

Network coding works by separating messages into smaller bits of "evidence" that can then be deduced by the destination node without transmitting, retransmitting or replicating the entire message. It enables this evidence to traverse multiple paths to and from intermediary nodes that then send it on to the endstation. It does not require additional capacity or routes -- it simply mixes evidence of messages into bit streams already supported by an existing network infrastructure.

"It's like eavesdropping. You listen to what's going on around you, you form an opinion and then you improve the overall throughput and capacity by actually remembering and using the information you have," said Sumeet Sandhu, principal investigator for cooperative wireless communication at Intel Research.

Network coding could work its way into any number of products from routers to wireless systems or take the form of entirely new devices dubbed network coders. Intel sees the potential for the technology to extend the range of wireless base stations. Microsoft is already trialing network coding to make its content distribution system more efficient (read "Microsoft's network coding plan"). Other big network players, such as Cisco Systems Inc., are keeping their plans hush hush for now and declined to say more than this, through a spokesman: "We are investigating network coding as the theory helps distinguish a variety of different types of traffic, then prioritizes them to help increase the capacity of the network. Right now, we do not offer any specific network coding products."

Decoding network coding

To give you a better feel for what network coding is all about, here's a further technical explanation.

Network coding manipulates the data inside the packet itself through what's called a "bitwise exclusive or" (xor) operation to combine the information with that of another packet. A bitwise xor takes two bit patterns and performs the logical operation on each pair of corresponding bits, assigning a number "1" if the two bits are different and "0" if they are the same.