Differentiated Services Codepoint (DSCP) mapping
A codepoint must have an 802.1p priority assignment (0 - 7) before you can configure a policy for prioritizing packets. 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 (qos dscp-map priority command).
The DSCP Policy Table associates an 802.1p priority with a specific ToS byte codepoint in an IPv4 packet. This enables 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 table below.
Syntax:
show qos dscp-map
Displays the DSCP Policy Table.
DSCP policy |
802.1p priority |
DSCP policy |
802.1p priority |
DSCP policy |
802.1p priority |
|---|---|---|---|---|---|
000000 |
No-override |
010110 |
3* |
101011 |
No-override |
000001 |
No-override |
010111 |
No-override |
101100 |
No-override |
000010 |
No-override |
011000 |
No-override |
101101 |
No-override |
000011 |
No-override |
011001 |
No-override |
101110 |
7** |
000100 |
No-override |
011010 |
4* |
101111 |
No-override |
000101 |
No-override |
011011 |
No-override |
110000 |
No-override |
000110 |
No-override |
011100 |
4* |
110001 |
No-override |
000111 |
No-override |
011101 |
No-override |
110010 |
No-override |
001000 |
No-override |
011110 |
5* |
110011 |
No-override |
001001 |
No-override |
011111 |
No-override |
110100 |
No-override |
001010 |
1* |
100000 |
No-override |
110101 |
No-override |
001011 |
No-override |
100001 |
No-override |
110110 |
No-override |
001100 |
1* |
100010 |
6* |
110111 |
No-override |
001101 |
No-override |
100011 |
No-override |
111000 |
No-override |
001110 |
2* |
100100 |
6* |
111001 |
No-override |
001111 |
No-override |
100101 |
No-override |
111010 |
No-override |
010000 |
No-override |
100110 |
7* |
111011 |
No-override |
010001 |
No-override |
100111 |
No-override |
111100 |
No-override |
010010 |
0* |
101000 |
No-override |
111101 |
No-override |
010011 |
No-override |
101001 |
No-override |
111110 |
No-override |
010100 |
0* |
101010 |
No-override |
111111 |
No-override |
010101 |
No-override |
||||
*Assured Forwarding codepoints; configured by default on the switches covered in this guide. **Expedited Forwarding codepoint configured by default. |
|||||