Huawei Quidway S6500 Series User Manual

Operation Manual - QoS/ACL
Quidway S6500 Series Ethernet Switches Chapter 2 QoS Configuration
Huawei Technologies Proprietary
2-3
2.1.8 Traffic Priority
The Ethernet Switch can deliver priority tag service for some special packets. The tags
include TOS, DSCP and 802.1p, etc., which can be used and defined in different QoS
modules.
2.1.9 Queue Scheduling
When congestion occurs, several packets will compete for the resources. The queue
scheduling algorithms are used to overcome the problem. Here introduce Strict-Priority
Queue (SP) queue scheduling algorithm.
1) SP
Packets sent via this
interface
high priority
Low priority
Classify
Packets sent
Sending queueDequeue
queue 7
queue 6
queue 5
queue 4
queue 3
queue 2
queue 1
queue 0
Figure 2-1 SP
The SP is specially designed for the key service application. A significant feature of the
key service is requiring for priority to enjoy the service to reduce the responding delay
when congestion occurs. Take 8 egress queues for each port as example, SP divides
the queue of port into up to 8 kinds, from high-priority queue to low-priority queue
(which are shown as the Queue 7, 6, 5, 4, 3, 2, 1 and 0 in turn) with sequentially
reduced priority.
During the progress of queue dispatching, strictly following the priority order from high
to low, the SP gives preference to and sends the packets in the higher-priority queue
first. When the higher-priority queue is empty it will send the packets in the
lower-priority group. In this way, put the packets of higher priority service in the
higher-priority queue and put the packets of lower priority, like e-mail, in the
lower-priority queue, can guarantee the key service packets of higher priority are

Huawei Quidway S6500 Series Specifications

General

Brand	Huawei
Model	Quidway S6500 Series
Category	Network Router
Language	English