VoIP phone amusements

[John Gray]

We have:

• Configuration server, connected to
• HP Procurve PoE switch with two VLANs: Voice and Data, connected to
• VoIP PoE phones

The configuration server downloads a phone's configuration, and provides IP addresses on the Voice LAN, when the phone is connected to the network.

Now the unusual bit.
In some instances (well, four) an unmanaged TP-Link PoE switch is interspersed between one of the Procurve ports and three of the VoIP phones.

For two of the four instances of TP-Link switches, this works without incident, and the phones get their config and IP addresses happily.
In the other two instances, it doesn't work and the phones crash with IP addresses from the Data LAN - NBG...

My question is: would you expect things to work correctly with the TP-Link PoE switches connected, and should all the "data" just go straight through - or not?

[Rudi]

Sorry John, I have no idea about this one?

[StuartR]

I would br very reluctant to use switches that don't understand VLANs on a network like that.

[John Gray]

It is a case of 'needs must' - too many desks, phones and PCs, and insufficient ethernet wall sockets.

Each VoIP phone has an ethernet output for a PC, and everything works nicely provided that you program the phones with fixed IP addresses rather than using DHCP from the 'phone server'.
The PCs (being VLAN unaware) work happily with DHCP addresses being handed out by the Cisco router.

The TP-Link PoE switches are unintelligent unmanaged boxes, and I was expecting/hoping that all the TAG and any other VLAN data would be passed through them from the Procurve switch to the connected phones. And in two of the four instances this seems to be the case!

A theory currently being worked on is that the level of phone firmware might be implicated...