  An interesting distributed adaptive CSMA MAC protocol, called adaptive CSMA,
was proposed recently to schedule any strictly feasible achievable rates inside
the capacity region. Of particular interest is the fact that the adaptive CSMA
can achieve a system utility arbitrarily close to that is achievable under a
central scheduler. However, a specially designed transport-layer rate
controller is needed for this result. An outstanding question is whether the
widely-installed TCP Reno is compatible with adaptive CSMA and can achieve the
same result. The answer to this question will determine how close to practical
deployment adaptive CSMA is. Our answer is yes and no. First, we observe that
running TCP Reno directly over adaptive CSMA results in severe starvation
problems. Effectively, its performance is no better than that of TCP Reno over
legacy CSMA (IEEE 802.11), and the potentials of adaptive CSMA cannot be
realized. Fortunately, we find that multi-connection TCP Reno over adaptive
CSMA with active queue management can materialize the advantages of adaptive
CSMA. NS-2 simulations demonstrate that our solution can alleviate starvation
and achieve fair and efficient rate allocation. Multi-connection TCP can be
implemented at either application or transport layer. Application-layer
implementation requires no kernel modification, making the solution readily
deployable in networks running adaptive CSMA.
