Extend Your Wireless Network with a Second Wireless Router

July 26, 2011 -- Scenario: In your office (or home) your router wireless signal doesn't reach all of the space effectively. You may have electrical interference from other equipment or multiple walls that wireless signals don't penetrate. With your wired network this wasn't an issue, but now with laptops, netbooks, tablets, and smartphones so common, it has become an issue.

Situation 1: A business owner acquires a new laptop and finds that the wireless signal in the light-industrial plant is too weak in the office attached to the plant. There is already wired network access to the office computers. The solution is to add a second wireless router in the office wired to the local network.

Situation 2: The ISP provided ADSL modem/router supported WPA-PSK TKIP wireless security. A new mobile phone supports WiFi but only with WPA2 security. The fix may be to have the ISP provide an updated modem/router but this isn't always easy. The immediate solution is to add a second inexpensive wireless router to the local network that supports the higher security method.

I will describe an effective and inexpensive solution that will help some readers with similar situations that I have encountered. That said, there are other technical ways to accomplish this including the installation of dedicated Wireless Access Point (WAP) devices which tend to be more expensive devices.

A typical configuration that many of you will encounter is shown below. I'll walk through the basic steps to add the second router to extend your wireless network by configuring the router as a Wireless Access Point. The solution described here presumes you have wired network access close to the point where you need extended WiFi access, or you are able to run a network cable to the distant point. The inclusion of network switches may not be necessary in your situation as most retail routers include up to four LAN ports. If you have cable/broadband internet service with your ISP, your modem will likely be separate from your primary router -- no difference here, just an extra box. One cable will run from the modem to the WAN port on your router.

1. Generally, no changes are required on your primary router. The illustration below is with a Siemens modem/router but is typical of many ADSL/DSL modem/routers found in the home and office. Again, if your are on cable/broadband service, your modem and router will be separate devices. You only need to be aware of the IP address of the router (usually your Default Gateway) and the DCHP server range (to avoid conflicts). It will help to know the Wireless Channel also. In this example, the router address is 192.168.1.254.

2. The wireless router we added in our illustration is a D-Link model but just about any wireless router should work.

You will need to connect a network cable from the primary modem/router (any available LAN port) to the second router. This may be routed through another switch or directly connected. The network cable into the back of the second router should be plugged into any LAN port (typically 1-4) and not the special WAN (or UpLink) port. This last point is important.

3. The second router will need to be configued with an IP address within the valid address range of the primary router. The default for most D-Link routers is 192.168.0.1. I changed this to 192.168.1.1 so as not to conflict with other IP addresses on the network. You will also need to disable (not enable) the built-in DHCP Server, so that the second router is not assigning IP addresses to connecting devices. Select a different broadcast channel and SSID from the primary router; and select your Wireless Security Mode and wireless key or pass phrase. In the configuration illustrated, the second router acts as a Wireless Access Point and as a network switch (with the spare ports available for other wired devices).

4. I recommend running a free WiFi scanning program called inSSIDer on your laptop. You should be able to see all WiFi networks in range including both routers broadcasting their SSID. The full display will graphically show the relative signal strength for each. This can help you diagnose or confirm wireless issues in the first place as you move to different places within your office or home.

5. Proper configuration of your network can optimize traffic. For instance, your older router may only be supportting 10-100Mbps throughput, while a new router or network switch might offer 1000Mbps (1 Gbps) throughput. If much of your network traffic is between computers within your office (or home) then it makes sense to connect those devices to one Gigabit switch, and then connect the switch to the router for internet access. Routers and switches are relatively inexpensive these days, so upgrading an old box or network card might give your network a nice performance boost.

Referencing the network illustration above, a laptop in the distant office will be able to connect to the second wireless router and be part of the entire office network with access to the internet also. The IP address will be supplied by the DHCP server running on the primary modem/router. Depending on the network settings in Windows 7, the laptop might connect automatically to the strongest network signal when near either the primary router or the office router. Alternatively, a specific network can be manually selected.

--MLJ