  We study and compare the Shannon capacity region and the stable throughput
region for a random access system in which source nodes multicast their
messages to multiple destination nodes. Under an erasure channel model which
accounts for interference and allows for multipacket reception, we first
characterize the Shannon capacity region. We then consider a queueing-theoretic
formulation and characterize the stable throughput region for two different
transmission policies: a retransmission policy and random linear coding. Our
results indicate that for large blocklengths, the random linear coding policy
provides a higher stable throughput than the retransmission policy.
Furthermore, our results provide an example of a transmission policy for which
the Shannon capacity region strictly outer bounds the stable throughput region,
which contradicts an unproven conjecture that the Shannon capacity and stable
throughput coincide for random access systems.
