Is device id header in CDP is mandatory field for device to accept VoIP VLAN?

[Yaron Moshkovitz]

Hi,

My IPP fail to get VoIP VLAN out of CDP when using (cat4500es8-UNIVERSALK9-M), Version 03.08.01.E RELEASE SOFTWARE (fc2), ROM: 15.1(1r)SG6.

CDP is configured correctly, i know that since other IPP vendors get VoIP VLAN from CDP on the same switch.

when connecting the IPP to switch running (cat4500e-UNIVERSALK9-M), Version 03.04.04.SG RELEASE SOFTWARE (fc2), ROM: 15.0(1r)SG3.

it succeed to get the VoIP VLAN.

Comparing the CDP headers between the IPP vendors, i noticed that the IPP doesn't advertise any info in the 'device id' CDP header.

Modifying the IPP FW to one that supports CDP device id header, and the IPP got the VoIP VLAN.

the question is why did the IPP with the non-exist device id header succeed to get correct VoIP VLAN on older switch?

Is there any modifications on what cisco expects in the CDP headers? is the device id header is mandatory?

Why Cisco are not backward compatible?

Thanks!

[Thomas Johnston]

Cisco switches also support LLDP. If you phone supports it, make sure its enabled.

[Yaron Moshkovitz]

Thanks Thomas!

We want to keep one standard + both (phone & switch) supports the CDP.

The question is whether 'device id' header in CDP protocol is mandatory field?

In case answer is yes- why on previous versions it worked?

In case answer is no- why does phone fail to get VoIP vlan? is it cisco bug?

Thanks,

Yaron.