cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
8223
Views
0
Helpful
1
Replies
Highlighted

Auto QoS on 2960, 3560 and 3750

Hi All

Our access layer consists of c2950, c2960 and c3560 switches, which uplink to c3750 switches, and we have Mitel phones attached at the access layer. We have various software versions ranging from 12.1(11) to 12.2(50). I need to setup qos just for the phones, so I think auto qos is the simplest way.

From reading the config guides for the 2960 and 3560 it seems to me I can enable auto qos with two commands: "auto qos voip cisco-phone" on the access ports with phones directly attached, and "auto qos voip trust" on any L2 or L3 port that connects to another switch. As I understand it, these commands will enable qos, setup all default queues, and trust the cos markings of any traffic received from an IP phone. All traffic sent from an IP phone automatically has a cos value of 5, so when it reaches the switch it should get placed in queue 2 for ingress traffic and queue 1 for egress traffic. Once these commands are entered on all switches across the network all voip traffic should be prioritised when interfaces are congested.

When I entered "auto qos voip cisco-phone" and "auto qos voip trust" on our 2960's eveything seemed to be fine [qos enabled, queues automatically setup, etc]. "show mls qos interface" showed that all ports with Mitel phones directly attached had a trust state of "trust cos", all ports with no phone attached had a trust state of "not trusted", and all ports had the following attached policy map for ingress "AutoQoS-Police-CiscoPhone". All ports also had the command "priority queue out" automatically configured.

However, when I entered "auto qos voip cisco-phone" and "auto qos voip trust" on one of our access layer 3560's we got a different result. All queues seemed to be enabled, but none of the ports were trusting the cos of attached phones. "show mls qos interface" showed that all ports with a Mitel phone directly attached had a trust state of "not trusted", none of the ports had a policy map for ingress [and there were no class maps or policy maps autoconfigured] and none of the ports had the command "priority queue out" automatically configured. The only way I could get the 3560 to trust the incoming cos of the phones was to use the command "auto qos voip trust" instead of "auto qos voip cisco-phone" and manually add the policy map, class maps and "priority queue out" commands.

I'm concerned that qos may not be operating correctly on the 3560's [just because all the automatic commands that were configured on the 2960 were not configured on the 3560].

Can anyone confirm if:

1) My understanding of how to enable autoqos is correct [e.g. just use commands "auto qos voip cisco-phone" and "auto qos voip trust"]

2) Does auto qos need to be enabled differently on a 3560/3750 from a 2960 [the config guide seems the same for all].

Thanks in advance.

1 REPLY 1
Highlighted
Beginner

Don't know if you got through, but to answer your question, you can use the "auto qos viop trust" command to use AutoQoS with the Mitel IP Phones.

The "cisco-phone" parameter limits the QoS scope to the cisco phone, but because you are using a Mitel phone, the switch will not recognise it and thus not trust the CoS or DSCP headers being sent.

And the command is the same regardless of switch. The AutoQoS command will generate different commands as the queues are different for each switch.

Content for Community-Ad