C
ONFIGURING
THE
S
WITCH
3-174
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 replaces the ToS bits, but it retains
backward compatibility with the three precedence bits so that non-DSCP
compliant, ToS-enabled 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 4-230
Console(config)#interface ethernet 1/1 4-144
Console(config-if)#map ip precedence 1 cos 0 4-232
Console(config-if)#end
Console#show map ip precedence ethernet 1/1 4-236
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 3-13 Mapping DSCP Priority Values
IP DSCP Value CoS Value
00
81
10, 12, 14, 16 2