Cable Modem and DSL Router
Introduction
When there is a single cable modem and if you want to share the modem connection between up to 4 computers, this can be achieved in two ways. One is with a software running on a PC. The other way is with a small stand-alone box, called router. All the standard requirements like DHCP client for the WAN side, DHCP server for the LAN side, NAT (Network Address Translation) are handled by this box and so there is no need for any special computer settings to make this to work. One can also save any extra charges for additional IP addresses, if required to be paid to the ISP by way of using this box..
How to connect ?
The above diagram illustrates the cabling set up for one Modem with two computers through a router box.The WAN connection is limited to 10 Mbps Ethernet. Normally, as most broadband connections never gets over about 1.5 Mbps for any periods of time, it is considered that the connection will operate satisfactorily.
Configuration
The configuration can be done through a set of built in web pages. You can connect to using any standard web browser like Internet Explorer or Netscape. The first page will hold all configuration required by most of the users.
Configuration of WAN side
Router Name – This is equivalent to the computer name in Windows networking set-up as used by some ISP’s.
Domain Name – equivalent to the workgroup name in Windows networking set-up as used by some ISP’s.
Obtain IP address automatically – get the IP address from the ISP through DHCP.
Or Specify an IP Address, Subnet Mask, Default Gateway Address and DNS (Domain Name Server) Address – this is required if the ISP uses static IP addresses and not DHCP.
Configuration of LAN side
LAN IP Address and Subnet Mask – sets the range of addresses that are used on the home LAN. Any private LAN should use non-routable addresses in the 10.0.0.0, 172.16.0.0 or 192.168.0.0 blocks.
There is a built-in DHCP server on the LAN side of the computer, hence the computer can get the IP address and set-up automatically through DHCP. This makes it very easy to set up the client computers. Also. Since a laptop computer is being used both at work and at home, it will be able to just plug in, if the workplace is also using DHCP. Reconfiguration of the laptop may not be required .
An example of a link system router is given below (This type of configuration would work with other type of routers also):
