graemeporter Tue, 02/05/2008 - 06:06
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Hi Andrei,

If you're using a modern switch (such as the 2960, 3560, or 3750), you should be able to use the AutoQoS feature to automatically define port configuration.

Go into the switchport that you're having problems with:

switch(config)# interface FastEthernet 0/1


Then you need to tell the switch you want to apply automatic QoS to this port, optimising it for connection to a Cisco IP Communicator client:

switch(config-if)# auto qos voip cisco-softphone

After a pause while AutoQoS is applied to the switch (globally), the command prompt will return. If you show the running config on the switch you will find that AutoQoS has applied a number of commands at the global level, and on the interface you entered the commands on, you should see something like this (I have marked the new commands with ***):

interface FastEthernet0/1

switchport access vlan 10

switchport mode access

switchport voice vlan 20

no logging event link-status

srr-queue bandwidth share 10 10 60 20 ***

srr-queue bandwidth shape 10 0 0 0 ***

mls qos trust device cisco-phone ***

mls qos trust cos ***

no snmp trap link-status

auto qos voip cisco-softphone

spanning-tree portfast

If your switch doesn't support the AutoQoS command, then I don't know if you can really do much else on the switching level. I've not encountered anything personally.

If you can set this up, you may find it improves things for you. Let me know if it makes things better.

Kind regards,


a.cruea1980 Mon, 02/25/2008 - 10:28
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There's at least one other thing you can do without AutoQoS, and that is set up CBWFQ with access-lists to match VoIP traffic.

iraban Mon, 02/25/2008 - 08:54
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Not that I know off.

but then again you can always do some QoS,CoS in the switch, do some policing, depends on the enviroment, type of problem and situation.

please rate if this is helpful


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