Problem with Nortel i2004 phones and cisco 3560 switches

[kaylo]

I do not know much about VOIP, VOIP phones or PBXs.  I recently encountered an issue where I could not connect to the PBX with a Nortel i2004 phone after I migrated the phones from a Cisco 6509 to a Cisco 3560 series switch. 
When the phones were connected to the 6509 switch they used Access VLAN 9 and they all worked fine.  There was NOT an auxillary VLAN configured on the switch.  The phones were not connected to PCs either.  When I migrated to the Cisco 3560 I configured the ports the same way the 6509 was configured, without a Voice VLAN  That was the way the 6509 was configured so i thought it would work.  The phones got IP addresses form the DHCP server and talked to the PBX through the firewall but they got stuck trying to connect to the S1 server.  I finally got the phones to work by configuring a random Voice VLAN.  The phone did not use the Voice VLAN.  They still used the original access VLAN but they were able to connected and make calls.  My question is why does a Voice VLAN have to be configured on a 3560 switchport for the phones to work even though it was not being used?  I am stumped and all of the googleing and sarching online has yielded no definative answer. 
Thanks
 

[Flintstone]

Hi kaylo and welcome to the forum,

I think you can enter the following command on both switches to see if there is any difference on the port configuration:

show interface <port> switchport

CheerZ and good luck

[kaylo]

Flintstone

The main difference between the 2 switches is the 6509 runs on CatOS while the 3560 runs on IOS.  I looked at the configs and there are not any huge differences.

3560 port config                                                             
 description 
 switchport access vlan 7
 switchport mode access
 switchport port-security
 switchport port-security aging time 1
 switchport port-security aging type inactivity
 no snmp trap link-status
 no cdp enable
 spanning-tree portfast
end
 
6509 port config
set vlan 7   
set port name
set port security 8/24 enable age 0 maximum 1 shutdown 10 unicast-flood enable violation shutdown
set port security 8/24 00-0a-e4-08-6b-39
set trunk 8/24 off negotiate 1-1005,1025-4094
set spantree portfast    8/1-48 disable

Access VLAN 9 is the VLAN the phone uses.  The phone works on the 6509 using access VLAN 9 and no voice(auxillary) VLAN but it does not work on the 3560 unless i define a voice VLAN, and that Voice VLAN is not the VLAN the phone uses.  Why does a Voice VLAN have to be defined on a 3560 for the phone to work?

Thanks for the feedback

kaylo

[Flintstone]

Hi kaylo,

I agree you shouldn't need to configure a voice Vlan?

If you have time to troubleshoot, try 'Sniffing' the connectivity between the VoIP Phone and the switch and see what is happening?

CheerZ

[Michael McNamara]

3560 port config                                                             
...
 switchport mode access
...

6509 port config
...
set trunk 8/24 off negotiate 1-1005,1025-4094

You have one switch configured at access and one configured at trunk... that's the difference.

Cheers

[kaylo]

I appreciate the feedback.  The port on the 6509 switch that has the configuration "set trunk 8/24 off negotiate 1-1005,1025-4094" is not configured to trunk.  That command turns trunking off on that port.

I did some research over the weekend and I found an obscure command configured on the 6509 that might be tagging all packets  in and out of the interfaces.  The command "set port dot1q-all-tagged" is enabled on the port.  I think this command makes the switch tag every port on the switchport.  I think tagging is the reason fo the different actions taken by the different network devices.  If anyone can verify this I would be very grateful.

Thanks