3Com 10014299 manual Configuring Congestion Management, Configuring Fifo Queuing

686CHAPTER 49: CONGESTION MANAGEMENT

occupied by each traffic is (each priority + 1)/ the sum of each priority plus 1, that is, 1/15, 2/15, 3/15, 4/15 and 5/15.

For example, there are total 4 flows currently, and the priority levels of three of them are 4, and that of one of them is 5, and then the total number of the allocated bandwidth is:

(4 + 1) x 3 + (5 + 1) = 21

Then, the bandwidths of the three flows with the priority levels of 4 are 5/21, and the bandwidth of the flows with the priority level of 5 is 6/21.

Configuring

Congestion

Management

Configuring FIFO

Queuing

This section describes the following types of congestion management:

■Configuring FIFO Queuing

■Configuring Priority Queuing

■Configuring Custom Queuing (CQ)

■Configuring WFQ

To configure FIFO queuing, perform the following configurations in the interface view.

Table 720 Configure the First In First Out Queuing

Operation	Command
Configure the length of FIFO queue	qos fifo queue-length queue-length
Recover the default value of the FIFO	undo qos	fifo queue-length
queue length

Configuring Priority Queuing

By default, the length of the FIFO queue is 75, with the value ranging 1 to 1024.

Priority queuing configuration includes:

■Configuring priority queuing

■Applying the priority-list queuing group to the interface

■Specifying the queue length of the priority-list queuing

Configuring priority queuing

The priority queuing classifies the packets according to a given policy, and all the packets are divided into 4 classifications, each of which corresponds to one of the 4 queues of PQ respectively. Then the packet is input to the corresponding queue according to its classification. The 4 PQ queues are: high priority queue (top), medium priority queue (middle), normal priority queue (normal) and low priority queue (bottom) with priority levels decreased sequentially. Upon the transmission of packets, they are sequentially transmitted according to their priority orders, that is, the packets in the top queue are first transmitted, then the packets in the middle queue are transmitted, and then the packets in the normal queue are transmitted, and finally the packets in the bottom queue are transmitted.

The priority queuing includes up to 16 groups (the value range of pql-indexis 1 to 16), each of which specifies which types of data packets input which queue, the