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Walkthrough Wednesdays

Help setup QoS on C2950 SI

Hello, I´m on a network witha  lot of switches, I configured auto QoS on non C2950 SI, but now I need to configure

Queueing and Scheduling on those, because they do not support auto QoS. Witch command can I use to to this, and

how I can check if is working later?

Jason Masker

What version of IOS are you running?  Have you taken a look at Configuring QoS on page 553 of this guide?

Cisco Internetwork Operating System Software

IOS (tm) C2950 Software (C2950-I6Q4L2-M), Version 12.1(22)EA4, RELEASE SOFTWARE                                                              (fc1)

I read, but it´s telling me about Auto QoS, but does not support this command.

Do I need to uplink ports in trust state? The others switch is configured as dscp, but this version on my switch also does not support that, do i need to use de command: mls qos trust cos pass-t dscp

or I just use: mls qos co ?


Here is config from one of my 2960 switches with Autoqos enabled.


mls qos map cos-dscp 0 8 16 26 32 46 48 56
mls qos min-reserve 5 170
mls qos min-reserve 6 85
mls qos min-reserve 7 51
mls qos min-reserve 8 34
mls qos

On switchport:

mls qos trust cos
auto qos voip trust
wrr-queue bandwidth 10 20 70 1
wrr-queue min-reserve 1 5
wrr-queue min-reserve 2 6
wrr-queue min-reserve 3 7
wrr-queue min-reserve 4 8
wrr-queue cos-map 1 0 1
wrr-queue cos-map 2 2 4
wrr-queue cos-map 3 3 6 7
wrr-queue cos-map 4 5
priority-queue out
spanning-tree portfast

See if you can run through the global commands and then the commands on the switchport.  These are the commands that AutoQoS adds.  It might not work due to different model and IOS but its worth a try.

Good luck!

paolo bevilacqua
Hall of Fame Master

You should not need to configure any QoS on a switched LAN.

The is no congestion on LAN,so QoS is not necessary.

Especialy the scheduling and queing commands only generate confusing configuration, while the defaults are perfectly adeguate.

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