Cisco 7931 phones not getting IP

[Vignesh Ekanathan]

Hello all,

I am currently having issue with Cisco 7931 phones not getting any IP which is located in their workshop (It's a donga and located 20 meters from main office). 

Here is the scenario:

VLAN 1 - 192.168.28.x/24

VLAN 100 - 10.2.1.x/24

In the main office, where the main UC520, core switch are located, all the phones are working okay and it's getting IP.

However, the phones that are located in the workshop are not getting any IP and the phone status is stuck at "Configuring IP".

But, the PC's that are connected to the phones are getting VLAN 1 IP and internet is working okay. 

Upon checking the switch in both offices, the trunk mode is set to allow both VLAN 1 and VLAN 100. 

I have factory reset both switches, but nothing has worked so far. 

If I take the phone from the Donga back to the main office, the phone gets IP and works without any issues. 

I definitely think it's something to do with trunking on the switch. 

The switch located in the workshop is ESW520-24P-PoE.

What other options do I have?

[Leo Laohoo]

Put a PC port into a Voice VLAN and reboot the PC. See if the PC gets an IP address for the phones.

[Julio E. Moisa]

Hi,

Have you verified if CDP is enabled on the switch?, try to configure a PC over the voice VLAN as Leo suggested, also verify the IP Helper address for that VLAN.

[Richard Burts]

I wonder if there is a helper address at the remote site. It looks to me that the voice vlan at remote is the same as at the main office and is trunked. So they are depending on trunking to forward the broadcast frames. Are we sure that the remote switch has the same configuration for voice vlan that the office has?

HTH

Rick

[Vignesh Ekanathan]

Thanks for the reply everyone. 

I found out the issue. It was with the switch configuration. 

Switch had both VLAN 1 and VLAN 100 configured. I had to remove VLAN 100 from the switch.

Once removed, the phones got IP address and started working okay. 

[Richard Burts]

Vignesh

Thank you for posting back to the forum and letting us know that you have solved the problem. It is interesting to know that the problem was having vlan 100 on the switch and that removing that vlan allowed the phones to get addresses and to work.

HTH

Rick