Cisco Catalyst 2000 Configuration Handbook page 254

Tip On an IOS switch, the 1q4t queue is serviced by a weighted round-robin (WRR)
algorithm. Therefore, the thresholds must be set with the wrr-queue threshold command.
(Optional) Use weighted random early detection (WRED) receive queues:
■
(interface) rcv-queue random-detect min-threshold queue-id thr1-min
thr2-min ...
(interface) rcv-queue random-detect max-threshold queue-id thr1-max
thr2-max ...
For 1p1q8t port types, WRED is used. The queue-id is 1 (standard queue) or
2 (priority queue). Two limits are used for each of the eight queue thresh-
olds: a minimum thr1-min (1 to 100 percent) and a maximum thr1-max (1 to
100 percent).
When the buffer is below the minimum level, no frames are dropped. As the
buffer rises above the minimum but below the maximum, the chances that
frames will be dropped increases. Above the maximum level, all frames are
dropped.
Tip The IOS 1p1q8t receive queues also require the wrr-queue random-detect queue-id
command to enable the WRED drop thresholds.
c. (Optional) Tune ingress scheduling and congestion avoidance:
(interface) rcv-queue cos-map queue-id threshold-id cos-list
OR
(interface) wrr-queue cos-map queue-id threshold-id cos-list
If the inbound CoS values are trusted from Step 3c or a QoS policy, frames with
certain CoS values can be mapped and sent to specific ingress queues and
thresholds. The cos-list can be a single value (0 to 7), multiple values separated
by commas, or a hyphenated range of values. This mapping is set for all switch
ports (COS switch) or per-interface (IOS switch).
The port-type is the type of queuing available, as seen by the show queueing
interface command. The queue-id (1 for standard or 2 for strict priority) and the
threshold-id (1 to 4) identify the specific queue and threshold where inbound
frames will be queued. The range of values is dependent upon the switch port
hardware.
By default when QoS is enabled, CoS 0 through 7 are mapped to the standard
ingress queue (queue 1). If a strict-priority queue (queue 2) is supported (queue
type begins with 1p...), CoS 5 is mapped there.
Chapter 13: Quality of Service 233