I work with a charity and, by default - not qualification, am responsible for the network.
We have a Vigor 2800 adsl router which allows the broadband (ADSL) connection to be 'shared' among the other computers on the network.

A while ago I needed to expand the network and decided to change the main hubs for switches. So now we have 2 x 8 ports stitches connected into the Vigor and then branching out into various offices.

I have had a few other problems, but will keep things easy by concentrating on one in partic.

In one office I am trying to connect an IP phone (Grandstream gxp2000) into the wall socket. If I connect it direct, the phone reports that it is unable to get an IP address. However, if I connect the phone to a simple 5 port hub (via the uplink port), then connect the phone into the hub - Bingo Ip address in seconds.

I have tried using a crossover cable to connect the phone direct to the office wall socket, but no success, still can't get an IP address.

Why do I need the hub ????


You shouldn't Hubs are dumb devices they do nothing except share bandwidth i think you are probeblt on the right tracks with the cabling.

i hate hubs, use switches instead.

Think of a switch as the post office. You send a message and they know exactly where to send it becuase of the address you put on the message. This is alot more effective as opposed to them going door to door knocking and asking until they find the right house (what a hub does).

Just to confirm, you are saying that if you plug your phone directly into the network it doesn't recieve an ip, but if you go through a hub and then into the network it does?

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