Allocating Bandwidth Between Standard Transmit Queues - Cisco WS-SUP32-GE-3B - Supervisor Engine 32 Software Configuration Manual

Configuring PFC QoS
To map CoS values to tail-drop thresholds, perform this task:
Command
Step 1
Router(config)# interface type
Step 2
Router(config-if)# wrr-queue cos-map
transmit_queue_# threshold_# cos1 [cos2 [cos3
[cos4 [cos5 [cos6 [cos7 [cos8]]]]]]]
Step 3
Router(config-if)# no wrr-queue cos-map
Step 4
Router(config-if)# end
Step 5
Router# show queueing interface type
1. type = ethernet, fastethernet, gigabitethernet, or tengigabitethernet
When mapping CoS values to a tail-drop threshold, note the following information:
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This example shows how to map the CoS values 0 and 1 to standard transmit queue 1/threshold 1 for Fast
Ethernet port 5/36:
Router# configure terminal
Enter configuration commands, one per line.
Router(config)# interface fastethernet 5/36
Router(config-if)# wrr-queue cos-map 1 1 0 1
Router(config-if)# end
Router#
This example shows how to verify the configuration:
Router# show queueing interface fastethernet 5/36 | begin queue thresh cos-map
<...Output Truncated...>
Router#

Allocating Bandwidth Between Standard Transmit Queues

The switch transmits frames from one standard queue at a time using one of these dequeuing algorithms,
which use percentages or weights to allocate relative bandwidth to each queue as it is serviced in a
round-robin fashion:
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Catalyst Supervisor Engine 32 PISA Cisco IOS Software Configuration Guide, Release 12.2ZY
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1
slot/port
1
slot/port
Use the transmit queue and threshold numbers.
Queue 1 is the low-priority standard transmit queue.
Queue 2 is the high-priority standard transmit queue.
There are two thresholds in each queue.
Enter up to 8 CoS values to map to the threshold.
queue thresh cos-map
---------------------------------------
1 1 0 1
1 2 2 3
2 1 4 5
2 2 6 7
Shaped round robin (SRR)—SRR allows a queue to use only the allocated bandwidth. Supported as
an option on Supervisor Engine 32 SFP 1p3q8t ports.
Deficit weighted round robin (DWRR)—DWRR keeps track of any lower-priority queue
under-transmission caused by traffic in a higher-priority queue and compensates in the next round.
DWRR is the dequeuing algorithm on 1p3q1t, 1p2q1t, 1p3q8t and 1p7q8t ports.
Purpose
Selects the interface to configure.
Maps CoS values to a tail-drop threshold.
Reverts to the default mapping.
Exits configuration mode.
Verifies the configuration.
End with CNTL/Z.
Chapter 38 Configuring PFC QoS
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