Assigning DSCP policies to packets matching specified TCP and UDP port applications (Example)

Port Applications	DSCP Policies
	DSCP	Priority
23-UDP	000111	7
80-TCP	000101	5
914-TCP	000010	1
1001-UDP	000010	1

Procedure

Determine whether the DSCP codepoints that you want to use to mark matching packets already have an 802.1p priority assigned, which could indicate use by existing applications (show qos dscp-map command).

NOTE:

A DSCP codepoint must also have a priority configured before you can use it to mark matching packets.

Viewing the current DSCP-map configuration

switch(config)# show qos dscp-map

  DSCP -> 802.p priority mappings
  NOTE: ‘qos type-of-service diff-services’ must be configured 
         before DSCP is honored on inbound traffic.

  DSCP CodePoint DSCP Value 802.1p tag   DSCP Policy name
  -------------- ---------- -----------  ---------------------------
  000000         0          0            cs0
  000001         1          No-override
  000010         2          No-override
  000011         3          No-override
  000100         4          No-override
  000101         5          No-override
  000110         6          No-override
  000111         7          No-override
  001000         8          1            cs1
  001001         9          No-override

Configure the DSCP policies for the codepoints you want to use.
Assigning priorities to the selected DSCPs
Assign the DSCP policies to the selected TCP/UDP port applications and display the result.
Configuring a DSCP policy for global TCP/UDP port classifiers
The switch applies the DSCP policies as shown in the preceding image to IP packets with the specified source and destination TCP/UDP port applications that are received in the switch. The switch manages the packets as follows:
1. Overwrites the original DSCPs in the selected packets with the new DSCPs specified in the above policies.
2. Assigns the 802.1p priorities in the above policies to the selected packets.