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IP Phones not working on new switch

Hello everyone!  I have just installed a new 3560x on our network to replace an old C3560.  We have a UC520 here as well for our IP phone system (which I am totally new to).  Ok, I have setup the new switch with the same config as the old switch with the exception of the IP address of VLAN 1 interface.  I gave it a new address which is on the same subnet as everything else on vlan 1 of course.  VLAN 100 is my voice VLAN.  IF I plug a 7960 IP phone into a port on the new switch that has no config for that port, the phone works, but it picks up an IP address from my VLAN 1.  IF I configure the swichport with the correct config, the IP phone just hangs on Configuring IP.  I'm new to VoIP, so I'm probably not aware of some setting, but when I do a show run on both switches new and old one, the configs are just about line for line identical.  I will say that the old switch is IOS 12.1 and the new switch is IOS 12.2.  Also, the new switch does see all the vlans on the network.  Below is the switchport config on the new switch:

interface GigabitEthernet0/1

switchport mode access

switchport voice vlan 100

spanning-tree portfast

This is exactly what is on each port of the old switch with the exception that they are FastEthernet ports instead of GigabitEthernet ports.  Can anyone shed some light on this or point me in the right direction?

Thank You,


Everyone's tags (4)

IP Phones not working on new switch

Can you post the entire config, include of the GW.


Community Member

IP Phones not working on new switch

Ok, I figured it out.  I thought I had made the port on the 3560x that goes to the UC520 a trunk port, but evidently I was wrong.  After making it a trunk port, it started working correctly.  Thanks Leonard for your help!

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