The equilibrium behaviour of store-and-forward packet-switched networks is studied under realistic conditions via a network of queues. A network with a general mesh topology is considered. Switching nodes have a finite number of store-and-forward buffers, and communication channels are not perfect. A node-node protocol with positive acknowledgment and retransmission is modelled, and consumes part of the channel buffers. A new approach is employed to obtain buffer overflow probabilities using a truncated multiserver queue with channel buffers being both the servers and the storage places. The developed model accounts explicitly for the acknowledgment delays and interactions among adjacent queues. The principal results are mean buffer size and overflow probability, retransmission probability and the mean delays as functions of the number of buffers, traffic levels and the error rate of data transfer. The developed model is validated by comparison with simulation results.