Figure 45-8 Diagram for WRR queuingch port. WRR configures a weight value forueue, for example: w7, w6, w5, w4, w3, w2, w1, and w0 respectively for queue 7 through queue0. A weight value indicates the proportion of resources available for a queue. On a 100-Mbps port,Mbps × 1/(5+5+3+3+1+1+1+1)) bandwidth at least, and the disadvantager a long timevscheCongestion Avoidancethe memory) reaches certaindegree.et dropping policyTCP connection synchronization. If a queue drops packets of multiple, the TCP connections will turn to the state of congestion avoidanceraffics to be regulated. The traffic peak will then occur in a certain future time.e.WREDY rly detection (WRE id global TCP session synchronization.WRR queue-scheduling algorithm schedules all the queues in turn and every queue can be assured ofa certain service time.In a typical 3Com switch there are eight output queues on eaeach qconfigure the weight value of WRR queue-scheduling algorithm to 5, 5, 3, 3, 1, 1, 1, and 1(corresponding to w7, w6, w5, w4, w3, w2, w1, and w0 in order). In this way, the queue with the lowestpriority can get 5 Mbps (100of SP queue-scheduling that the packets in queues with lower priority may not get service fois avoided. Another advantage of WRR queue is that: though the queues are scheduled in order, theser ice time for each queue is not fixed; that is to say, if a queue is empty, the next queue will beduled. In this way, the bandwidth resources are made full use.Congestion may cause network resource unavailable and thus need to be prevented. As a type of flowcontrol mechanism, congestion avoidance aims to relieve network load through traffic adjusting. Withcongestion avoidance configuration performed, packets are dropped in advance when the utilization ofcertain network resources (such as output queues or buffer created inTraditional packTail drop is adopted in traditional packet drop policies. It drops all the newly arrived packets when thecurrent queue length reaches a specific value.Such a policy will result in globalTCP connections simultaneouslyand slow startup for the tConsequently, the network traffic jitters all the timou can use weighted random ea D) to avo45-12
