This work investigates the effect of finite buffer sizes on the throughput
capacity and packet delay of line networks with packet erasure links that have
perfect feedback. These performance measures are shown to be linked to the
stationary distribution of an underlying irreducible Markov chain that models
the system exactly. Using simple strategies, bounds on the throughput capacity
are derived. The work then presents two iterative schemes to approximate the
steady-state distribution of node occupancies by decoupling the chain to
smaller queueing blocks. These approximate solutions are used to understand the
effect of buffer sizes on throughput capacity and the distribution of packet
delay. Using the exact modeling for line networks, it is shown that the
throughput capacity is unaltered in the absence of hop-by-hop feedback provided
packet-level network coding is allowed. Finally, using simulations, it is
confirmed that the proposed framework yields accurate estimates of the
throughput capacity and delay distribution and captures the vital trends and
tradeoffs in these networks.Comment: 19 pages, 14 figures, accepted in IEEE Transactions on Information
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