Class of Service Configuration

3-197

3
CLI – The following example globally enables IP Precedence service on the switch,
maps IP Precedence value 1 to CoS value 0 (on port 1), and then displays the IP
Precedence settings.
Note: Mapping specific values for IP Precedence is implemented as an interface
configuration command, but any changes will apply to the all interfaces on the
switch.

Mapping DSCP Priority

The DSCP is six bits wide, allowing coding for up to 64 different forwarding
behaviors. The DSCP retains backward compatibility with the three precedence bits
so that non-DSCP compliant devices will not conflict with the DSCP mapping. Based
on network policies, different kinds of traffic can be marked for different kinds of
forwarding. The DSCP default values are defined in the following table. Note that all
the DSCP values that are not specified are mapped to CoS value 0.
Console(config)#map ip precedence 4-251
Console(config)#interface ethernet 1/1 4-155
Console(config-if)#map ip precedence 1 cos 0 4-252
Console(config-if)#end
Console#show map ip precedence ethernet 1/1 4-255
Precedence mapping status: enabled
Port Precedence COS
--------- ---------- ---
Eth 1/ 1 0 0
Eth 1/ 1 1 0
Eth 1/ 1 2 2
Eth 1/ 1 3 3
Eth 1/ 1 4 4
Eth 1/ 1 5 5
Eth 1/ 1 6 6
Eth 1/ 1 7 7
Console#
Table 3-18 Mapping DSCP Priority Values
IP DSCP Value CoS Value
00
81
10, 12, 14, 16 2
18, 20, 22, 24 3
26, 28, 30, 32, 34, 36 4
38, 40, 42 5
48 6
46, 56 7