Fuzzy Explicit Marking for Congestion Control in Differentiated Services Networks

This paper presents a new active queue management scheme, Fuzzy Explicit Marking (FEM), implemented within the differentiated services (Diff-Serv) framework to provide congestion control using a fuzzy logic control approach. Network congestion control remains a critical and high priority issue. The rapid growth of the Internet and increased demand to use the Internet for timesensitive voice and video applications necessitate the design and utilization of effective congestion control algorithms, especially for new architectures, such as DiffServ. As a result, a number of researchers are now looking at alternative schemes to TCP congestion control. RED (Random Early Detection) and its variants are one of these alternatives to provide quality of service (QoS) in TCP/IP Diff-Serv networks. The proposed fuzzy logic approach for congestion control allows the use of linguistic knowledge to capture the dynamics of nonlinear probability marking functions and offer effective implementation, use multiple inputs to capture the (dynamic) state of the network more accurately, enable finer tuning for packet marking behaviors (either dropping a packet or setting its ECN –Explicit Congestion Notificationbit) for aggregated flows, and thus provide better QoS to different types of data streams, such as TCP/FTP traffic or TCP/Web-like traffic, whilst maintaining high utilization.