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.

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.