06-11-2007 11:21 AM - edited 03-14-2019 10:00 PM
hi
i have a 7960 Ip phone and a pc connected on its access port. All i want to use QoS in order to give priority to voice traffic, so i made this configuration for one interface and i would like to know if it has a meaning(3500XL switch) ...
switchport access vlan 10
switchport voice vlan 20
switchport mode trunk
switchport trunk encapsulation dot1q
switchport trunk native vlan 10
mls qos trust cos
thanks
06-11-2007 01:35 PM
friend,
You do not require to configure a trunk between the switch and a cisco IP phone.
All you need is
switchport access vlan 10
switchport voice vlan 20
switchport trunk native vlan 10
mls qos trust cos or DSCP
A specialized trunk will be negotiated between the switch and the phone capable of carrying only 2 vlans,one for data and one for voice and this is recommended by cisco.
Also make sure you trust the QoS settings on the upstream switch trunks.
Configuration provided by you is mostly used when connecting an avaya ip phone to a cisco switch
HTH, rate if it does
Narayan
06-11-2007 09:14 PM
thanks for the replay
i found an opportunity to give a try with one phone (7911 ) without the trunking port command and the phone confiuration seems not to procced . stays at registering situation without a responce.
is there anything else i have to look?
thanks
06-11-2007 09:38 PM
Trunk configs are definitely not required.
you can check the status of the port by issuing show interface fastEthernet x/y switchport
you should see the voice vlan and the trunk options
can you try connecting a working phone i.e the one which is already registered to CCM
HTH, rate if it does
Narayan
06-11-2007 11:13 PM
thats the output .....
YPP-SW-3#sh int fa 0/37 switchport
Name: Fa0/37
Switchport: Enabled
Administrative mode: static access
Operational Mode: static access
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: dot1q
Negotiation of Trunking: Disabled
Access Mode VLAN: 113 (VLAN0113)
Trunking Native Mode VLAN: 113 (VLAN0113)
Trunking VLANs Enabled: NONE
Pruning VLANs Enabled: NONE
Priority for untagged frames: 0
Override vlan tag priority: FALSE
Voice VLAN: 10
Appliance trust: none
shows trunking disable. is it possible the old IOS ver to cause this?
06-11-2007 11:29 PM
Have you disabled CDP by any chnace on the interface?
Be aware that the special-case 802.1Q trunk automatically is enabled through a CDP information exchange between the switch and the IP Phone.
Regarding QoS for voice traffic, all you have to do is enable QoS globally and make sure you trust the DSCP at the trunks and uplinks
HTH, rate if it does
Narayan
12-11-2007 04:48 PM
I had a similar problem, I disabled CDP on an interface and it the iptel couldn't register anymore.
As this discussion is about trunk and uplinks I would like to know what to do if the links between the access switches and the core is L3.
Currently we use stacks of Cat3750's which have 4 fiber uplinks to a Cat6500.
We would like to enable L3 uplinks (and use EIGRP) instead of trunks uplinks. Is this possible and how ?
My understanding is that dot1Q is L2 or am I wrong ?
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