Filter
Top Products
Quality of Service (QoS): Managing Bandwidth More Effectively
Using QoS Classifiers To Configure Quality of Service for Outbound Traffic
Steps for Creating a DSCP Policy Based on TCP/UDP Port Number
Classifiers. This procedure creates a DSCP policy for IP packets carrying
the selected UDP or TCP port-number classifier.
1. Identify the TCP or UDP port-number classifier you want to use for
assigning a DSCP policy.
2. Determine the DSCP policy for packets carrying the selected TCP or UDP
port number.
a. Determine the DSCP you want to assign to the selected packets. (This
codepoint will be used to overwrite the DSCP carried in packets
received from upstream devices.)
b. Determine the 802.1p priority you want to assign to the DSCP.
3. Configure the DSCP policy by using qos dscp-map to configure the priority
to the codepoint you selected in step 2a. (For details, refer to the example
later in this section, and to “Differentiated Services Codepoint (DSCP)
Mapping” on page 15-51.)
No t e A codepoint must have an 802.1p priority assignment (0 - 7) before you can
configure a policy for prioritizing packets by TCP or UDP port numbers. If a
codepoint you want to use shows No-override in the Priority column of the
DSCP map (show qos dscp-map), then you must assign a 0 - 7 priority before
proceeding.
4. Configure the switch to assign the DSCP policy to packets with the
specified TCP or UDP port number.
Syntax: qos dscp-map < codepoint > priority < 0 - 7 >
This command is optional if a priority has already
been assigned to the < codepoint >. The command creates
a DSCP policy by assigning an 802.1p priority to a
specific DSCP. When the switch applies this policy to a
packet, the priority determines the packet’s queue in
the outbound port to which it is sent. If the packet leaves
the switch in a tagged VLAN, it carries the 802.1p
priority with it to the next downstream device. If the
packet is IPv4, the packet’s DSCP will be replaced by the
codepoint specified in this command. (Default: For
most codepoints,
No-override. See figure 15-8 on page
15-52.)
15-17