87
Step Operation
Description
2
Configure
the
mapping
relation between the 802.1P
priority and TC
Required. On
QoS→DiffServ→802.1P Priority
page,
configure the mapping relation between the 802.1P
priority and TC.
3
Select a schedule mode
Required. On
QoS→DiffServ→Schedule Mode
page, select a schedule mode.
9.1.2 Schedule Mode
On this page you can select a schedule mode for the switch. When the network is congested, the
problem that many packets compete for resources must be solved, usually in the way of queue
scheduling. The switch will control the forwarding sequence of the packets according to the priority
queues and scheduling algorithms you set. On this switch, the priority levels are labeled as TC0,
TC1… TC3.
Choose the menu
QoS
→DiffServ→Schedule Mode
to load the following page.
Figure 9-7 Schedule Mode
The following entries are displayed on this screen:
Schedule Mode Config
SP-Mode:
Strict-Priority Mode. In this mode, the queue with higher priority will
occupy the whole bandwidth. Packets in the queue with lower
priority are sent only when the queue with higher priority is empty.
WRR-Mode:
Weight Round Robin Mode. In this mode, packets in all the queues
are sent in order based on the weight value for each queue. The
weight value ratio of TC0, TC1, TC2 and TC3 is 1:2:4:8.
SP+WRR-Mode:
Strict-Pr Weight Round Robin Mode. In this mode, this switch
provides two scheduling groups, SP group and WRR group. Queues
in SP group and WRR group are scheduled strictly based on
strict-priority mode while the queues inside WRR group follow the
WRR mode. In SP+WRR mode, TC3 is in the SP group; TC0, TC1
and TC2 belong to the WRR group and the weight value ratio of
TC0, TC1 and TC2 is 1:2:4. In this way, when scheduling queues,
the switch allows TC3 to occupy the whole bandwidth following the
SP mode and the TC0, TC1 and TC2 in the WRR group will take up
the bandwidth according to their ratio 1:2:4.
Equ-Mode:
Equal-Mode. In this mode, all the queues occupy the bandwidth
equally. The weight value ratio of all the queues is 1:1:1:1.
9.1.3 802.1P Priority
On this page you can configure 802.1P priority. 802.1P gives the Pri field in 802.1Q tag a
recommended definition. This field is used to divide packets into 8 priorities. When 802.1P Priority is
