Review Analysis and Simulation of a Fair Queuing Algorithm

   
   
  Analysis and Simulation of a Fair Queuing Algorithm
   
  This paper presents a fair queuing algorithm and its role in controlling congestion in datagram networks.
   
  FQ algorithm proposes to maintain separate buffers for packets from each conversation.The paper describes an accurate definition of fairness, and tries to design the protocol for fairness in allocating throughput, buffer memory and promptness for all conversations. Instead of pure round robin algorithm, which is not fair because of the different sizes of packets, the transmission method is close to bit-to-bit round robin. In this algorithm, whenever the transmission of a packet finishes, the next packet with the smallest value of Fi(a)(number of bits sent by the conversation is transmitted. For fairness in buffer allocations, when the queue is full and a new packet arrives, the last packet from a source currently using the most buffer space is dropped.
   
  Authors compare proposed FQ algorithm with FCFS in networks with three different congestion control algorithms (generic fixed window size, JK flow control with dynamic window size, and DECbit with congestion bit feedback from gateways to hosts) running in hosts. FTP and Telnet sources over several topologies (different number of sources and gateways) are used in simulations to compare performance of two queuing algorithm regarding throughput, RTT, retransmitted packets and dropped packets. The overall evaluation shows a great improve in fairness when we use FQ especially under overload conditions.
   
  The proposed FQ algorithm has several advantages over FCFS queuing algorithm including fair allocation of bandwidth, lower delay for sources using less than their full share of bandwidth, and protection of ill-behaved sources. For future work, investigating the performance of FQ under more realistic load conditions, on larger networks, and interacting with routing algorithms will be suitable.
   
   
     
   

                 
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Received on Wed Sep 27 2006 - 19:54:12 EDT