SMART retransmission: performance with overload and random losses
Srinivasan Keshav, S.P. Morgan · 2002
Feedback flow control, in conjunction with limited buffering in the network, inevitably leads to packet loss. Effective congestion control requires not only effective flow control but also a good retransmission strategy. We present a new retransmission strategy called SMART that combines the best features of the traditional go-back-n and selective-retransmit strategies. We show, first, that go-back-n retransmission with static window flow control leads to congestion collapse when the nominal load exceeds the link capacity. Second, we can avert congestion collapse by replacing go-back-n with SMART retransmission, even with static window flow control. Third, SMART retransmission, when combined with packet-pair rate-based flow control, performs extremely well, both when losses are due to buffer overflows and when losses are random.