686 CHAPTER 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
This section describes the following types of congestion management:
■Configuring FIFO Queuing
■Configuring Priority Queuing
■Configuring Custom Queuing (CQ)
■Configuring WFQ
Configuring FIFO
Queuing To configure FIFO queuing, perform the following configurations in the interface
view.
Tabl e 720 Configure the First In First Out Queuing
By default, the length of the FIFO queue is 75, with the value ranging 1 to 1024.
Configuring Priority
Queuing 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-index is 1 to
16), each of which specifies which types of data packets input which queue, the
Operation Command
Configure the length of FIFO queue qos fifo queue-length queue-length
Recover the default value of the FIFO
queue length undo qos fifo queue-length