Smart AQM (SA): Pro-Active and Fair Queue Management for Internet Congestion Control

Active queue management (AQM) is a group of FIFO based queue management mechanisms in a router to support end-to-end congestion control in the Internet. Until random early detection (RED) was proposed by the internet engineering task force (IETF) for deploying[1], FIFO based tail drop (TD) was the only AQM mechanism used in the network. Two main functions are used in AQM: one is the congestion indicator (i.e., how to detect congestion) and the other is the congestion control function (i.e., how to avoid and control congestion). TD mechanism uses the instantaneous queue length as a congestion indicator, and drops packets when the buffer becomes full. However, it has been shown that TD has two well-known drawbacks, the lock-out and full queue phenomena [1], even though it is simple and easy to implement.