Network Coding in a Multicast Switch

— We consider the problem of serving multicast flows in a crossbar switch. We show that linear network coding across packets of a flow can sustain traffic patterns that cannot be served if network coding were not allowed. Thus, network coding leads to a larger rate region in a multicast crossbar switch. We demonstrate a traffic pattern which requires a switch speedup if coding is not allowed, whereas, with coding the speedup requirement is eliminated completely. In addition to throughput benefits, coding simplifies the characterization of the rate region. We give a graph-theoretic characterization of the rate region with fanout splitting and intra-flow coding, in terms of the stable set polytope of the “enhanced conflict graph” of the traffic pattern. Such a formulation is not known in the case of fanout splitting without coding. We show that computing the offline schedule (i.e. using prior knowledge of the flow arrival rates) can be reduced to certain graph coloring p...

• Type: Conference
• Year: 2007
• Where: INFOCOM
• Authors: Jay Kumar Sundararajan, Muriel Médard, MinJi Kim, Atilla Eryilmaz, Devavrat Shah, Ralf Koetter
• Keywords: Communications, INFOCOM 2007, Network Coding, Rate Region, Traffic Pattern