Enterprise QoS Solution Reference Network Design Guide

Chapter 2 Campus QoS Design
Version 3.3
Catalyst 2970/3560/3750—QoS Considerations and Design
Example 2-25 Show MLS QoS Interface Verification for a Catalyst 3550 Switch
CAT3550#show mls qos interface GigabitEthernet0/1 queueing
GigabitEthernet0/1
Egress expedite queue: ena ! Q4 is enabled as a PQ
wrr bandwidth weights:
qid-weights
1 – 5 ! Q1 is allocated 5%
2 – 25 ! Q2 is allocated 25%
3 – 70 ! Q3 is allocated 70&
4 - 1 when expedite queue is disabled
Dscp-threshold map:
d1 : d2 0 1 2 3 4 5 6 7 8 9
---------------------------------------
0 : 01 01 01 01 01 01 01 01 01 01
1 : 02 01 01 01 01 01 01 01 01 01 ! DSCP 10 is mapped to WRED T2
2 : 01 01 01 01 01 01 01 01 01 01
3 : 01 01 01 01 01 01 01 01 01 01
4 : 01 01 01 01 01 01 01 01 02 01 ! DSCP 48 is mapped to WRED T2
5 : 01 01 01 01 01 01 02 01 01 01 ! DSCP 56 is mapped to WRED T2
6 : 01 01 01 01
Cos-queue map:
cos-qid
0 – 2 ! Best-Effort is assigned to Q2
1 – 1 ! Scavenger and Bulk are assigned to Q1
2 – 3 ! Transactional Data and Network Management are assigned to Q3
3 – 3 ! Mission-Critical Data and call signaling are assigned to Q3
4 – 3 ! Interactive- and Streaming-Video are assigned to Q3
5 – 4 ! Voice is assigned to the priority queue: Q4
6 – 3 ! Internetwork Control (Routing) is assigned to Q3
7 – 3 ! Network Control (Spanning Tree) is assigned to Q3
CAT3550#
Catalyst 2970/3560/3750—QoS Considerations and Design
This section includes the following topics:
Catalyst 2970/3560/3750—Trusted Endpoint Model
Catalyst 2970/3560/3750—Auto QoS VoIP Model
Catalyst 2970/3560/3750—Untrusted PC + SoftPhone with Scavenger-Class QoS Model
Catalyst 2970/3560/3750—Untrusted Server with Scavenger-Class QoS Model
Catalyst 2970/3560/3750—Conditionally-Trusted IP Phone + PC with Scavenger-Class QoS (Basic)
Model
Catalyst 2970/3560/3750—Conditionally-Trusted IP Phone + PC with Scavenger-Class QoS
(Advanced) Model
Catalyst 2970/3560/3750—Queuing and Dropping
The Catalyst 2970 does not support Layer 3 routing and, as such, is restricted to the role of an
access-layer switch. The 3560 does support Layer 3 routing as well as inline power— a feature that is
rarely, if ever, required at the distribution layer—and so is only considered in an access-layer context.
The Catalyst 3750 also supports Layer 3 routing and may be found in either the access layer or the
distribution layer.
Figure 2-16 shows the QoS design options for access-layer Catalyst 2970s, 3560s, or 3750s, and
Figure 2-17 shows the QoS design recommendations for a distribution-layer Catalyst 3750.
Enterprise QoS Solution Reference Network Design Guide
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