Cisco Catalyst 2000 Configuration Handbook page 252

e. (Optional) Trust the inbound DSCP value by default:
(interface) mls qos trust dscp
You can choose to trust only the inbound DSCP value, keeping the ToS and
DSCP values intact. No other mapping derives the internal DSCP values.
f. (Optional) Map DSCP values between QoS domains.
Create a DSCP mutation map:
■
(global) mls qos map dscp-mutation dscp-mutation-name in-dscp to
out-dscp
When a switch port is at the boundary of a QoS domain, the inbound DSCP
values can be mapped to a set of different DSCP values. The mutation map
named dscp-mutation-name (text string) contains the inbound values in-
dscp (up to 8 values 0 to 63 separated by spaces) that are mapped to corre-
sponding new values out-dscp (up to 8 values 0 to 63 separated by spaces).
The command can be repeated if more than eight DSCP values need to be
mapped.
■ Apply a mutation map to an interface:
(interface) mls qos dscp-mutation dscp-mutation-name
By default, no DSCP mutation occurs on an interface. Otherwise, the muta-
tion map named dscp-mutation-name (text string) is used. Each Gigabit
Ethernet interface can have a different mutation map, whereas only one map
can be used on each group of 12 10/100 Ethernet interfaces.
(Optional) Tune the ingress port queues.
4.
Tip By default, the ingress ports use the congestion avoidance and scheduling in Table
13-2.
Table 13-2 Congestion Avoidance/Scheduling for Ingress Ports
Queue Threshold Number (Standard Queue)
Type
CoS: Percentage Tail-Drop or Low%/High% WRED
T1 T2
1q4t 0,1: 50% 2,3: 60%
1p1q4t 0,1: 50% 2,3: 0%
1p1q8t 0: 1:
40%/70% 40%/70%
T3 T4 T5
4,5: 80% 6,7: 100% —
4: 80% 6,7:100% —
2: 3: 4:
50%/80% 50%/80% 60%/90%
Chapter 13: Quality of Service 231
T6 T7
— —
— —
6: 7:
60%/90% 70%/100%
T8
—
—
—