Network coding for the Internet and wireless networks

Network coding is a promising routing generalization as it allows each node in a network to do some computation. Specifically, it is the transmission, encoding and reencoding of sent messages arriving at nodes inside the network, such that the transmitted messages can be decoded at their final destinations. In contrast to routing, network coding can improve throughput by pushing streams of information through the bottleneck link at the same time. The two streams are mixed together by taking their exclusive-OR bit-by-bit and sending the mixed stream through the link using network coding. In addition, network coding reduces the amount of energy required per packet of information multicast in a wireless network, not to mention the amount of delay as measured by the maximum number of hops for a packet to reach a receiver, for instance. The practicality of network coding relies on the concept of random coding, packet tagging and buffering. However, adopting network coding given the current capability of the Internet is still unlikely, as there is still a need to keep computation and per-flow state out of the core, a need for backward compatibility with a massive deployed base and a need for multipath routing to make network coding effective.