الفهرس 
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Abstract
Today, most of the Internet applications are based on the Transmission Control
Protocol (TCP). However, with the increasing number and variety of Internet
applications, congestion becomes a key issue. Generally, congestion problem
occurs when the traffic load increases. This problem decreases network utilization
and increases traffic delay. Therefore, the stability of the internet depends on the
TCP congestion control.
Due to the serious effectiveness of congestion problem in the Internet
performance, congestion control has the most concern in the network community.
Several End-to-End mechanisms were developed to overcome this problem.
However, most of the existing mechanisms adapt the sending rate at the sender,
when detecting congestion, without considering the network status. This behavior
degrades the Internet performance because congestion is happen. Hence, an
intelligent congestion control is required to avoid the mentioned problem.
This thesis presents a new intelligent control technique, called fuzzy controller or
Fuzzy logic, to adjust the sending rate at the sender dynamically based on the
network load. The intended controller is employed to enhance the existing TCPvarients and TCP-Vegas in order to avoid congestion. Nevertheless, the main
challenge in utilizing fuzzy controller is how to choice the number of membership
functions. Two different cases as considered: the first case employs 3-
memberships while the second case employs 5-memberships.
The performance of the proposed controller is evaluated by using the well-known
Network Simulator NS-2 considering a simple network and the AT&T real network.
The results are compared with the most recent protocols. The results indicate that
the proposed controller increases the throughput and decreases both the packet
loss and packet delay. Fathur, a greater performance is achieved with a large
number of membership functions.
Keywords: Congestion Control, Congestion avoidance,