Head-to-Tail: Managing Network Load through Random Delay Increase

Window-based congestion control is typically based on exhausting bandwidth capacity, which occasionally leads to transient congestion. Moreover, flow synchronization may deteriorate conditions further, leading to persistent or more severe congestion, which is experienced by flows through increasing queuing delays and packet retransmission. Head-to-Tail is a new approach to queue scheduling that aspires to alleviate this problem. When conditions at the router´s buffer indicate high risk for congestion, Head-to-Tail delays packets intentionally to fabricate the senders´ impression about the network load. This implicit signal to reduce the transmission rate allows for a responsive behavior prior to congestion. In this paper, we evaluated Head-to-Tail with TCP Vegas and compared it with RED and other TCP variants. The initial results indicate that congestion events and retransmissions can be significantly eliminated.