How to setup my 3Com ADSL Mos/Router as Sw.?

[OCdragon]

This issue may have been discussed a few times but I still don't know exactly how to set up my currently equipment: I would like to share my existing Broadband enabled Ethernet connection between a Xbox 360 and a PC using Ethernets, not wirelessly. I have the current Broadband Equipment:
Broadband access through O2 Box, and only 1 of its 4 Ethernet Ports is available because the remaining 3 LAN ports for the O2 Box have already been used up. Therefore I would like to:
1) Set up my spare 3Com ADSL Modem/Router (i.e. with 4 LAN Ports) as an Ethernet Sw. only, such that I can connect 1 of its 4 LAN ports to the only available LAN port of the O2 Box for Broardband access.
2) then connect 2 of the available 3 LAN Ports from the 3Com to my Xbox 360 and the PC respectively for Internet access.

As such I would like to know what:
a) How to set up my 3Com WAN and LAN ports respectively so that it will be functioning as an Ethernet Sw only.
b) I would like to maintain the O2 Box LANs as HDCP enabled, can I?

Thanks

[bLack0ut]

The first question is very easy; the difference between a router and a switch is that a router has a DHCP server. Just go into the settings of the router and disable the DHCP server. Then all the ports on your router will become ports for your switch.

I don't know much about O2, but I'm pretty certain that attaching the 3COM router won't affect your current setup at all.

[OCdragon]

Thank you for your reply! That means I should "disable" the DHCP Server for the LAN ports of my 3Com ADSL Modem/Router and only allocate "Static IP Addresses" for the 4 3Com LAN ports?
Thanks

[gangaskan]

The first question is very easy; the difference between a router and a switch is that a router has a DHCP server.

little misleading ;)


a router is a layer 3 device and it also does routing so you can get your internet access. not because its "just a switch with a dhcp server" it may appear like that, but there are alot more that goes behind the scenes.

[ppe1700]

basically what we're trying to say is that you just want to use the switch part of the 3com to extend your network. but the 3com may have a dhcp server set up, which would be bad for you if it gave out addresses since it would issue wrong ones, or possibly duplicates. (wrong because the 3com will probably issue the default gateway as itself - the 3com, so traffic for the internet will get to the 3com and not go anywhere else)
your 02 box also has a dhcp server which is good, and you are currently using it.

so, going forward, if you can disable the dhcp in the 3com, this is all you will need to do to connect it up to your existing network. only connect network devices to the lan ports. and a single connection between the 3com and 02 box is all you will need to extend the network.