Shawn (my brother) and I are busy implementing a Wireless network for a retirement village here in Cape Town. We’ve both got extensive experience with

wireless networks, but this is the biggest that both of us have worked on.

To be fair, it’s not so much implementation as it is taking over the wireless network from another company.

We’ve had very little say in what equipment is being used, what the positioning of the antennas are or how clients connect. This has created a very challenging network to work with.

We’ve taken it slowly, one day at a time and we’re not rushing to get it all wrapped up. Rather, we want to get it right.

We’ve stumbled across some new equipment, and been exposed to hardware we would probablynot have chosen for ourselves, but it’s interesting to work with none the less. The access points being used on-site are MikroTik 411 devices.

12 MikroTik devices covering about 4 acres of village and enabling a solid wifi connection to about 250 units of which only about 60 currently use the connection. The current connectivity is an incoming connection from a directional wifi antenna. Each client in the village uses a PPPoE connection to authenticate, which controls their bandwidth etc.

We’re changing this over to a fixed line, so each client will have an IP, and use a gateway to gain Internet access. We’ve put up a Linksys router, which we flashed with DD-WRT firmware giving us some more control over that cool little blue box.

From the Linksys router, we’re running a cable to an ADSL router which gives us an Internet connection. We’ll probably switch to a different line type in the future.

For initial testing we used the Linksys as the gateway (the ADSL is connected to the WAN port). We enabled WDS on the Linksys, and setup a Ubiquity Bullet 2 device. Both the Linksys and the Bullet 2 were given some encouragement with neat 12dBi antennas.

This worked surprisingly well, WDS was flaw

less and getting clients connected was a breeze. If you’re familiar with WDS the setup should take you more than an hour or so.

But this is where we ran into a brick wall at full tilt. The rest of the network is using MikroTik devices and as I mentioned earlier, neither Robert nor I have ever worked with them.

We managed to get one unused device and began playing with it. First course of action was to reset the device, and configure it from scratch, connecting it to our Linksys + Bullet 2 WDS setup.

Fail. We reset the device, got into the web interface, and were stumped. Configuration settings through a MikroTik 411 device web interface is useless. No I lie, less than useless. It’s just plain misleading and I don’t know why they bother.

After a few phone calls to suppliers and manufacturers, we were told that this is the wrong way to go about setting up a MikroTik router. The right way is to use a tool called Winbox.

Apparently what makes the MikroTik special is the software it runs. Unlike a traditional router like the Linksys that has a basic config system, the MikroTik runs something called RouterOS. Which is a version of Linux that runs on the router. Winbox is the software that configures RouterOS. You’re pretty much screwed if you don’t use Winbox.

So once we were in with Winbox the real fun and games started. Configuration is a complicated confusing maze of who knows what.

Some googling sent us down the right path. We probably configured the router a dozen times before we safely navigated the maze that was the configuration.

Firstly, the routers were all set to use the auxiliary connection for the 7dBi antenna, rather than the main connection. The current ISP obviously uses the aux, and has a different setup, mesh perhaps?

Then we found the holy grail of the MikroTik routers. They process a config in the order in which it was setup.

So for instance, if you setup WDS before you setup the WLAN, it’s a fail. Because when it starts up, it’ll try to configure the WDS, but have to WLAN to connect it to. Then when it brings up the WLAN it won’t know that the WDS needs it.

So the config steps we used in the end were really simple, and takes about 10 min to setup. But they must be done in the right order.

Reset the device, and connect to it using the LAN port.

Enable the WLAN, which is disabled by default.

Configure the WLAN. Set you mode, select your channel, give it a name etc etc.

Next you create a bridge. And enable RSTP. This is a very very important step.

Then you go back to the WLAN you enabled, and enable WDS, at first you enable it as dynamic, and connect it to bridge1 which you created in the previous step.

Now you go to the bridge, and the ports, and you link the wlan1 port to the bridge1 port.

Then, and only then do you give the WLAN an IP.

Our network uses security, so we’d head over to security, create a new security profile, called WEP, give it a key, and then go back to the WLAN settings and switch the security on.

The problem at this point is because you’re using dynamic WDS, the minute you have more than 2 devices, they will all WDS with each other, halving your connection speed each time until eventually your network dies a very rapid and painful death, and you can’t access anything.

To solve this, we switch the WDS to static and add the WDS devices manually. So the gateway (Linksys) is device 1, the first MikroTik is device2 etc etc. So Device2, would have Device 1, and Device 3’s MAC addresses as static WDS setup. Device 3 would have device 2 and 4 setup and so on and so on. The last device, lets say device 20 would have device 19 and device 1 (Linksys). So it basically creates a loop, with all the access points neatly daisy chained. If there is a failure in 1 place then there is another route for the traffic to flow.

Once you’ve been through the config above, you begin to appreciate Winbox. Makes saving and applying those setting a breeze, no need to reboot the device every time you make a change.

All in all MikroTik have been very helpful in helping us configure stuff. They have a great wiki an forum which is just full of super duper help.

Each MikroTik device has a 7dBi antenna helping it along, and for the size of the area we’re covering it’s working just fine. If I was building the network from scratch I’d use a Linksys for the gateway and Bullet 2’s everywhere I can.

Once we got the config right, rolling out the devices has been an absolute breeze.

Original post: Building wireless networks