02-21-2013 01:16 PM - edited 03-07-2019 11:52 AM
Hello All,
I have an issue on the Cat 3750 on the voice vlan; IP Phone not registering with PBX & Signaling Server. The ip phone hits dhcp and gets an ip address
from a data scope. Data scope does have dhcp options for voice, same as voice scope so it should work but it doesnt.
We removed the switchport access vlan 50 command, and left the switchport access voice vlan 51, and now the phone registers.
Anything I can check on the switch to make sure voice vlan is working? Any debug voice vlan commands?
The switch doesnt seem to distinguish voice and data traffic.
I check dhcp and both scopes vlan 50 and vlan 51 have the same configuration. Defautl GW is different of course
Catalyst 3750 is running 12.2(25)SEE2
Here is sample config
interface FastEthernet4/0/12
switchport access vlan 50
switchport mode access
switchport voice vlan 51
switchport port-security maximum 5
switchport port-security aging time 5
switchport port-security violation restrict
switchport port-security aging type inactivity
speed 100
duplex full
snmp trap mac-notification added
snmp trap mac-notification removed
spanning-tree portfast
spanning-tree guard root
ip dhcp snooping limit rate 10
02-21-2013 01:51 PM
What kind of IP phone are you using? If it doesn't support CDP you will need to enalbe LLDP on your switch for the phone to discover the voice vlan.
02-22-2013 09:56 AM
The ip phones are nortel 1120E, but there are others Nortel IP Phones (IP 2007) that have this issue.
I am focusing on the 1120Es.
The switches dont support lldp command, but the phones do. LLDP is enabled on the phone but that doesnt do any good
because the switch doesnt support. Not unless I upgrade the code
The ip phones were working without lldp up until now, why all of a sudden does it need it? (I agree with using lldp, going forward but not the root cause of the problem)
02-21-2013 03:24 PM
I think I've seen phones like this before. You need to enable dot1q trunking (allow data and voice VLAN) and leave the voice VLAN configuration.
02-22-2013 10:01 AM
dot1q trunking is enabled on the ip phone. As with the previous reply, not a bad suggestion but why did all 100+ ip phones work without dot1q trunking configured on the switch up until now.
Update
We moved one of the bad ip phones to a different stack of 3750s, and the problem didnt appear.
IP Phone registered, and got an ip from voice scope/subnet/vlan vlan 51. Moving the phone back to original stack, didnt bring back the problem either. ip phone still registered, came up and had ip from voice scope/subnet/vlan vlan 51.
In addition,
On original stack of 3750s I reconfigured the ip phone and its 8021q trunking (enabled by default), and I specified
the voice vlan id (51), and the data vlan id (50), and disabled LLDP.
I tested each individual command separately, and each didnt work by themselves, However, all 3 (configure concurrently) worked.
Rolled back each command to see if the problem reappeared, and it didnt.
02-22-2013 10:02 AM
Also,
both 3750 stacks are runningn same ios code 12.2 (25)SEE2.
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