Capillary multi-path routing with FEC for real-time multimedia

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Abstract - Application of forward error correction (FEC) in off-line streaming with large buffering time dramatically improves the quality and performance of communications in challenging network conditions. However real-time streaming puts hard restrictions on the buffer size leaving FEC helpless for combating long link failures on a single path route. Multi-path routing is another method, orthogonal to buffering, which can make FEC effective also for real-time streaming. In this paper we introduce a capillary routing algorithm offering layer by layer a wide range of multi-path routing topologies starting from a simple multi-path solution toward more reliable and secure schemes obtained by recursively spreading individual sub-flows. The friendliness of a particular multi-path routing scheme is rated by a measure called Failure Recovery Redundancy Overall Requirement (FRROR), which is proportional to the total amount of FEC codes required for combating the individual failures of all links in the multi-path route. A dozen of capillary routing layers, built on several hundreds of network samples obtained from a random walk wireless Mobile Ad-Hoc Network (MANET), are rated with FRROR. We show that the overall requirement in FEC decreases substantially as the spreading of the routing grows.