Cisco 500 series Administration Manual page 420

Configuring Quality of Service
Configuring QoS - General
STEP 1
STEP 2
STEP 3
Cisco 500 Series Stackable Managed Switch Administration Guide
Mapping DSCP to Queue
The DSCP (IP Differentiated Services Code Point) to Queue page maps DSCP 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.
The DSCP to Queue mapping is applicable to IP packets if:
• The switch is in QoS Basic mode and DSCP is the trusted mode, or
• The switch is in QoS Advanced mode and the packets belongs to flows that
is DSCP trusted
Non-IP packets are always classified to the best-effort queue
To map DSCP to queues:
Click Quality of Service > General > DSCP to Queue. The DSCP to Queue page
is displayed.
The DSCP to Queue page contains Ingress DSCP. It displays the DSCP value in
the incoming packet and its associated class.
Select the Output Queue (traffic forwarding queue) to which the DSCP value is
mapped.
Click Apply. The Running Configuration file is updated.
Configuring Bandwidth
The Bandwidth page enables users to define two values, Ingress Rate Limit and
Egress Shaping Rate, which determine how much traffic the system can receive
and send.
The ingress rate limit is the number of bits per second that can be received from
the ingress interface. Excess bandwidth above this limit is discarded.
The following values are entered for egress shaping:
25
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