Qos and Auto Qos

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Dec 2nd, 2007
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i have 2 3750 core switchen with routing and a couple of 3560 connected to it. We are going to connect some ip phones on the network. Now i turned Qos on, on the 3560 with mls qos and the fastethernet interfaces Auto Qos VoIP trust (as it aren't Cisco ip phones).

The ip server will be connected to the 3750. Do i need to turn on the qos and autoqos command on the 3750? What command do I need on my uplinks on the 3560 and on the downlinks to the 3560 on the 3750 switches?



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royalblues Sun, 12/02/2007 - 10:24
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you should configure to trust the uplink ports of the 3750 and the 3560.

mls qos trust dscp/cos

I would also enable SRR and put the voice traffic(DSCP 46/cos5) in the priority queue. This can be achieved either manually which gives greater control or either via Auto QoS.

Since thes earen't Cisco voip phones, i would like you to check the vendor documentation to find the QoS tagging done by these phones as it is quite possible that Auto qos might not place the required traffic in the right queues



bvsnarayana03 Sun, 12/02/2007 - 20:08
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You need to add the command "mls qos trust" on the trunks & accessports connected to IP phones to make the switch trust the markings done by the IP phone, otherwise switch rewrites the marking & those tagged by phone are lost.


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