Deadlock-Free TCP Over High- Speed Internet

In this paper, we consider TCP throughput deadlock problems caused by an interplay between the Nagle algorithm, delayed acknowledgment algorithm, and several implementation details. For some combinations of send and receive buffers, a TCP sender cannot send more segments due to the Nagle algorithm and, at the same time, a TCP receiver cannot acknowledge more segments received due to the delayed acknowledgment algorithm. The outcome is a deadlock, which can only be resolved by the receiver's timer. Although the deadlock can take place in any types of networks, it is generally more difficult to ensure deadlock-free connections on high-speed networks. Moreover, the impact is much more significant on high-speed networks, and the deadlock renders the connection practically unusable. Several straightforward solutions, such as turning off the Nagle algorithm and acknowledging every segment, have been proposed; however, they reintroduce the same problems that they were initially designed for. In this paper we propose an adaptive acknowledgment algorithm (A 3) to eliminate throughput deadlocks on the receiver side while preserving the original intent of employing the Nagle algorithm and delayed acknowledgment. An A 3-receiver uses the same delayed acknowledgment as before, but with an additional component to adaptively