I am currently investigating an issue between our 3750 switches running version 12.2.(50)SE and 12.2(44)SE and Nortel 1110 phones running firmware version:0623C6J
Our issue is that certain sites need to have their IP addresses statically configured, as on boot up, the phones find a data vlan ip address. We are not running port security.
We have 2 types of sites in our enterprise:
1/ larger sites, where the 3750 switches are used as access, and other devices such as cat 6500 are providing the routing. thus the switches the phones plug into are L2 only
2/ smaller sites where the 3750 switches are both access and L3. These sites have the stack connect directly to the WAN router, and have an IP helper address on the voice SVI in the stack.
It is on the second type of site our issue is happening, and I am not sure if the problem is an LLDP-MED one where the voice vlan is passed across properly, or an issue with passing the DHCP request through the helper address correctly?
Packet traces of the LLDP-MED interaction show the L3 switches have 2 Network Policy TLVs sent from the switch (as compared to one for the L2 switches). The first is for a voice application (with a vlan id attached), and the second a Voice Signalling application, with no voice vlan.