Using Differentiated Services Codepoint (DSCP) mapping

The DSCP Policy Table associates an 802.1p priority with a DSCP codepoint in an IPv4/IPv6 packet. Using DSCP codepoints in your network allows you to set a LAN policy that operates independently of 802.1Q VLAN-tagging.

In the default state, most of the 64 codepoints do not assign an 802.1p priority, as indicated by No-override in the following Default DSCP policy table. However, some codepoints, such as Assured Forwarding and Expedited Forwarding, have a default 802.1p priority setting.

Use the following commands to display the DSCP Policy table, configure the codepoint-priority assignments, and assign optional names to the codepoints.

Syntax:


show qos dscp-map

Displays the DSCP Policy table.


qos dscp-map codepoint priority0 - 7 [name ascii-string]

Configures an 802.1p priority for the specified codepoint and an optional (DSCP policy) name.


no qos dscp-map codepoint

Removes the currently configured 802.1p priority that is associated with the specified codepoint and displays the No-override setting. The codepoint policy name, if configured, is also removed.


no qos dscp-map codepointname

Deletes only the policy name, if configured, for the specified codepoint.

Table 27: The default DSCP policy table

DSCP Policy

802.1p Priority

DSCP Policy

802.1p Priority

DSCP Policy

802.1p Priority

000000

No-override

010110

31

101011

No-override

000001

No-override 0 10111 No-override 101100 No-override

000010

No-override 011000 No-override 101101 No-override

000011

No-override 011001 No-override 101110

71No-override

000100

No-override 011010 41 101111 No-override

000101

No-override 011011 No-override 110000 No-override

000110

No-override 011100 41 110001 No-override
000111 No-override 011101 No-override 110010 No-override
001000 No-override 011110 51 110011 No-override
001001 No-override 011111 No-override 110100 No-override
001010 No-override 100000 No-override 110101 No-override
001011

11

100001 No-override 110110 No-override
001100 No-override 100010 61 110111 No-override
001101 21 100011 No-override 111000 No-override
001110 No-override 100100 61 111001 No-override
001111 No-override 100101 No-override 111010 No-override
010000 No-override 100110 71 111011 No-override
010001 01 100111 No-override 111100 No-override
010010 No-override 101000 No-override 111101 No-override
010011 01 101001 No-override 111110 No-override
010100 No-override 101010 No-override 111111  
010101          
1

Expedited Forwarding codepoint configured by default.