The simplest device you can use to create a local area network is a hub.  It is the equivalent of a terminal block.  It will send data to all ports.  A more intelligent device is a network switch.  A switch queries data packets on a basic level and only sends data to the required ports.  A router is the smartest and most complicated of the bunch.  Routers come in all shapes and sizes – from the small, four-port broadband routers that are very popular to the large industrial strength devices that drive the internet itself.

A simple way to think of a router is as a computer that can be programmed to understand, possibly manipulate, and route the data that it’s being asked to handle. Many routers today are, in fact, little computers dedicated to the task of routing network traffic.  As far as simple traffic routing is concerned, a router operates exactly as a switch, learning the location of the computers on its connections and routing traffic only to those computers.  Consumer grade routers perform at minimum two additional and important tasks: DHCP and NAT.

In the ADSL era, you would typically use a single all-in-one device; a 4 port wireless broadband modem/router.  These days, with fiber optic connections to the node or premises, the modem component is no longer required.  Instead, the 4 port wireless broadband router (no modem) simply comes with a single WAN copper ethernet port to connect to an upsteam device/network.

If you already have a wireless router that you’d like to use only as a Wireless Access Point you can do as follows:

1. Change the IP of the wireless router to be in the same subnet as the main router.
   You may have to plug the device into a computer configured with a static IP address to do that.
2. Disable the wireless router’s DHCP server, so it wont conflict with the main router.
   Example:
   main router IP – 192.168.1.1 base IP, DHCP server range 192.168.1.100 to 192.168.1.200
   wireless AP IP – 192.168.1.201 to 253 base IP, DHCP disabled.
3. Connect the Wireless router to the main router using LAN ports on both routers using a crossover cable.
   Alternatively use the uplink port on one of the routers and a straight-through network cable.
4. Do not use the WAN port on the wireless router as this is not to be used for LAN connections.

Notes

• Wireless routers can only be used as an AP in Gateway mode (as opposed to repeater or bridge mode).
• All LAN clients should get their internal IPs from one router only.
• The WAN port on the Wireless Access Point router should not be connected to anything.
• You might want to turn off NAT on the Wireless Access Point router.

As soon as you disable DHCP on the wireless router, the web interface may no longer be available on some models(!)  A factory reset may be required if you need to make further changes to the settings at that point.  There should never be a need to configure a static IP address on your laptop – either connect with a cord to configure or connect to the wi-fi to test.