We consider multi-source multicast communication

scenarios in which each node has an aggregate outbound traffic

capacity and can directly communicate with any other node. This

is motivated by peer-to-peer (P2P) information dissemination

applications on the Internet in which the uplink capacity of nodes

is usually the bottleneck, being several times smaller than the

downlink capacity. We also allow the communication in a group

to be helped by non-receiver nodes (with respect to that group)

as relays. Extending an earlier result for the single source case,

we show that when coding is not allowed across sources, routing

is optimal. Also, as a rather surprising discovery, we show that

when all groups have pairwise identical or disjoint receivers,

routing is optimal even when coding across sources is allowed.

Moreover, routing along a linear number of trees per source is

sufficient to achieve this. The latter scenario is common in multiparty

conferencing systems, hence our results have interesting

practical applications in the design of infrastructure-less P2P

multiparty conferencing systems.

PDF file

In  Int'l Symp. on Information Theory

Publisher  Institute of Electrical and Electronics Engineers, Inc.
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