IP Phone ERROR 7960

[Charlie Mayes]

My IP phone will not download the software from the TFTP on the CME Router.

This is the error it has now. Protocol Application Invalid

Everything was working fine before. Does any one know how I can fix this issue?

[paolo bevilacqua]

You should use the the voice vlan, but if everything fails, connect directly to a PC and no VLANs.

[Charlie Mayes]

Do you have any information on how to properly setup a voice vlan so that the phones get their ip address different from the data vlan?

[paolo bevilacqua]

On a cisco switch:

interface x/y

switchport mode access

switchport access vlan ZZ

switchport voice vlan XX

[Charlie Mayes]

I mean if I have 2 DHCP pools how does the ip phone now what pool to get the ip address from? I am confused about how the layer 3 device would know how to route everything. I understand the config above but, am missing what needs to be configured on my 3550 layer 3 switch.

[paolo bevilacqua]

When the phones initially sends CDP, the switch understand there is a phone and they agree to use a tagged voice vlan for all phone activities. No configuration is necessary beside the one I gave you before. If you want inter-vlan routing done by the switch (recomended), just configure its vlan address as default gw in dhcp.

It is recommended that you keep the dhcp server for phones on the cme router, this way you don't have any dependency to a server and can easily configure, and monitor the entire boot process of a phone in a single place.

[Charlie Mayes]

Thanks so much Nick I think this finally makes sense to me. I guess I would have to setup subinterfaces on my router in order to run route data traffic and voice traffic right.

[paolo bevilacqua · Accepted solution]

Yes. More exactly, since the layer 3 switch will actually route traffic between data and voice vlan, the ccme router will use subinterfaces only to communicate with devices in said vlans.

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[Charlie Mayes]

Thanks for everything you have done to help me. I surely will leave you a rating. Thanks Again Nick.

[paolo bevilacqua]

You're welcome, thanks for the nice rating and good luck!