Enterprise QoS Solution Reference Network Design Guide

Chapter 2 Campus QoS Design
Version 3.3
Figure 2-12 Catalyst 2950 1P3Q1T Queuing Model
Catalyst 2950—QoS Considerations and Design
The configuration of the priority queue (Q4) and the bandwidth allocations for the remaining queues
(Q1, Q2 & Q3) are shown below.
Example 2-10 Catalyst 2950 Scheduling Configuration—1P3Q1T Example
CAT2950(config)#wrr-queue bandwidth 5 25 70 0 ! Q1-5%, Q2-25%, Q3-70%, Q4=PQ
CAT2950(config)#
Catalyst MLS QoS Verification Commands
show wrr-queue bandwidth
Application
Voice
Interactive-Video
Streaming-Video
Call-Signaling
Transactional Data
Network-Management
Bulk Data
This section includes the following commands:
show wrr-queue bandwidth
show wrr-queue cos-map
DSCP
Network Control -
Internetwork Control CS6
EF
AF41
CS4
Mission-Critical Data DSCP 25
AF31/CS3
AF21
CS2
AF11
Scavenger CS1
Best-Effort 0
The show wrr-queue bandwidth verification command displays the weights that have been assigned to
the queues. If the command returns a value of 0 for the weight of the fourth queue, this indicates that the
scheduler is operating in 1P3Q1T mode, with Q4 being the strict-priority queue.
In the following example, the scheduler has been configured for 1P3Q1T queuing: Q1 gets 5% of the
remaining bandwidth (after the priority queue has been fully-serviced), Q2 gets 25% and Q3 gets 70%.
Example 2-11 Show WRR-Queue Bandwidth Verification for a Catalyst 2950 Switch
CAT2950#show wrr-queue bandwidth
WRR Queue : 1 2 3 4
Bandwidth : 5 25 70 0 ! Q1 gets 5%, Q2 gets 25%, Q3 gets 70%, Q4 is PQ
CAT2950#
The CoS-to-Queue mapping configuration for the Catalyst 2950 is shown below.
CoS
CoS 7
CoS 6
CoS 5
CoS 4
CoS 4
CoS 3
CoS 3
CoS 2
CoS 2
CoS 1
CoS 1
0
CoS 5
CoS 7
CoS 6
CoS 4
CoS 3
CoS 2
CoS 0
1P3Q1T
Q4
Priority Queue
Queue 3
(70%)
Queue 2
(25%)
Queue 1 (5%)
CoS 1 Queue 1 (5%)
Enterprise QoS Solution Reference Network Design Guide
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