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 ????