Quality of Service
Configuring QoS - General
Cisco Small Business 200 Series Smart Switch Administration Guide
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20
•
Output Queue
—Select the egress queue to which the 802.1p priority is
mapped. Either four or eight egress queues are supported, where Queue 4
or Queue 8 is the highest priority egress queue and Queue1 is the lowest
priority.
STEP 3
For each 802.1p priority, select the Output Queue to which it is mapped.
STEP 4
Click
Apply
. 801.1p priority values to queues are mapped, and the Running
Configuration file is updated.
Mapping DSCP to Queue
The DSCP (IP Differentiated Services Code Point) to Queue page maps DSCP
values to egress queues. The DSCP to Queue Table determines the egress
queues of the incoming IP packets based on their DSCP values. The original VPT
(VLAN Priority Tag) of the packet is unchanged.
By simply changing the DSCP to Queue mapping and the Queue schedule method
and bandwidth allocation, it is possible to achieve the desired quality of services
in a network.
DSCP to Queue mapping is applicable to IP packets if DSCP is the trusted mode.
Non-IP packets are always classified to the best-effort queue.
The following tables describe the default DSCP to queue mapping for a 4 and 8
queue systems:
Table 4 DSCP to Queue Default Mapping – 4 Queues System
DSCP
63
55
47
39
31
23
15
7
Queue
3
3
4
3
3
2
1
1
DSCP
62
54
46
38
30
22
14
6
Queue
3
3
4
3
3
2
1
1
DSCP
61
53
45
37
29
21
13
5
Queue
3
3
4
3
3
2
1
1
DSCP
60
52
44
36
28
20
12
4
Queue
3
3
4
3
3
2
1
1
