Quality of Service
Configuring QoS - General
Cisco Small Business 200 Series Smart Switch Administration Guide 312
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• 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
3343 3 2 1 1
DSCP
62 54 46 38 30 22 14 6
Queue
3343 3 2 1 1
DSCP
61 53 45 37 29 21 13 5
Queue
3343 3 2 1 1
DSCP
60 52 44 36 28 20 12 4
Queue
3343 3 2 1 1
