non-CDP IP Phone & CoS

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Jun 25th, 2007
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I have a non-CDP ip phone connected to a dot1q trunk port on a cisco 2960 switch. The IP phone has eth2 port connected to a PC.

The phone has a menu setting for CoS whereby I can set the CoS to 5 for voice calls.

Will the Cisco switch give priority to the voice communication and understand the setting of CoS=5 ?


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thisisshanky Mon, 06/25/2007 - 11:11
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You can configure the switch port to trust cos. Depending on the type of switch being used you can trust the cos coming from the phone or even write an acl policy to remark packets from phone subnet to cos 5 or dscp ef.

paolo bevilacqua Mon, 07/02/2007 - 11:07
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Lots of experts here. For example, shanky and the answer he gave you. Do you understand it ?

rsabapathee Fri, 07/06/2007 - 02:30
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Sorry thisisshanky, I missed your response.

But isnt ACL affect layer 3 protocols only??

You said the switch can be set to trust the Cos from the IP phone. Lets say I have a 2960 switch. The problem is that since it is a non-CDP enabled phone, I will have to assume the switch will not recognise that an IP phone is connected, hence will not trust the phone packets.


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