Adding a new PoE Switch to an existing network

[debsawyer]

This is what I need to do. I ran one Cat 6 line to an office room. This room needs 5 phone lines. I purchased a PoE switch with 8 connections. There is an existing network. When I cabled the new PoE switch to the network, and plugged in the Cat 6 line to one of the PoE lines the phones did not work. When I place the PoE switch in the office room, and added lines to each phone, and ran a ethernet cable in each PoE jack it worked. What am I doing wrong? How to I get the PoE switch to work in the server room, and not run so much cable?

[deanwebb]

I don't think I follow you entirely... were you saying that you had one line for the phones in the first case? Would that mean that you had the phones connected to a smaller switch connected to the PoE switch?

[Dieselboy]

Hi OP - there's not really enough information to diagnose but I'll try and help.

Switches are not usually "just switches". If the existing network was set up extensively, the network might be blocking the new switch, it could be bpdu guard. This blocks layer 2 spanning tree messages, to protect the network from rogue switches causing network instability due to these spanning tree messages advertising the new switch with a better priority.

Another possibility is that if the network is set up properly for voip - there might be data and voice vlans configured. This could mean that the phones on the new switch might be in the data vlan, hence they're not working.

Have you configured the new switch at all?

When the phones are connected how you need them, do they:
- come up on the right VLAN / subnet? - go into the settings on the phone and check their IP address
- do the phones pick up a TFTP server? you can check this in the settings on the phone. The phones need to contact the TFTP server to download their config and register to the phone server.

What switches are they? Make / model etc

What phones are they? Make / model etc

Do the phones reside on a "voip" vlan?

Another "test" you can do is, if the phones come up with an ip addres but do not register, check the TFP server in the phone iteself. if it has not received a TFTP server, then you can manually configure the TFPT IP in the phone. If the network routes between the VLANs then the phones should work after that. this test wont "fix" your problem but will confirm a few things. Your network may only be set up properly to run phones on the voice vlan, and so leaving it this way might make the phones register but voice quality could be very poor or unusable.

A lot of assumptions we made by myself in this post to help you.

[debsawyer]

The new switch is:  TRENDnet® Unmanaged GREENnet PoE+ Ethernet Switch, 8-Ports (TPE-TG80G)

[Dieselboy]

Cannot help you any further without the other info I mentioned

[deanwebb]

Cannot help you any further without the other info I mentioned

This is true. If you don't know about the information requested, you could also give details on the other switches in the environment. If they are unmanaged switches or semi-managed switches, that may be why your original configuration didn't work. The one you are trying to use is unmanaged, so it will not carry any configuration information with it.