Deploying a Wireless Network in Your House

The rise of mobile elec­tron­ic devices, which need inter­net access has changed the demand we have on our home net­works. The days are over where one had a sin­gle com­put­er con­nect­ed with a wire to the broad-band inter­net modem. WLANs became very pop­u­lar because net­work client became more mobile. It start­ed with the note­books with which you could browse the net on your couch com­plete­ly wire­less­ly and it became even more pop­u­lar with the rise of the iPhones and iPads which should use the home inter­net access when used around the house. The ques­tion to solve is:

How can one achieve a good WLAN cov­er­age so that one can use his inter­net-depend­ing devices any­where at home?

The Simplest Solution — A Single Access Point

The sim­plest solu­tion would be to have only a sin­gle access point often com­bined with a router attached to the broad-band inter­net access of the house. This solu­tion is easy to deploy and main­tain, how­ev­er it could be that the cov­er­age over the entire house and dif­fer­ent floors is not complete.

Using a LAN as a Backbone for Different Floors

Anoth­er approach is pos­si­ble if there is a wired LAN in the house which for exam­ple con­nects the floors and is con­nect­ed to the inter­net access. To this wired LAN all the access points are attached and if their net­work name (the SSID) and the encryp­tion type and pass­word are the same, net­work device can do a han­dover between two access points. The advan­tage is that each wire­less access point is trans­mit­ting at full speed, because data is send over the air only once.

There are sev­er­al pos­si­bil­i­ties to sim­pli­fy the deploy­ment of the access points and make the whole set­up more man­age­able. The pro solu­tion would be to use a WLAN switch, which looks like a usu­al eth­er­net switch but is able to man­age attached access points. With such a switch it is pos­si­ble to enter the con­fig­u­ra­tion data only once and sent it out to all the com­pat­i­ble access points in the net­work. Oth­er more sophis­ti­cat­ed things like load bal­anc­ing and auto­mat­ic trans­mis­sion pow­er reg­u­la­tion are pos­si­ble. The draw­back like with every enter­prise-class prod­uct is price. To build such a net­work, a cen­tral WLAN switch with com­pat­i­ble access points have to be bought, which can get expensive.

There is how­ev­er a dif­fer­ent approach by Ubiq­ui­ti Net­works with their UniFi access points. These are APs which have log­ic in each AP but can be man­aged like a WLAN switch set­up. You just do not have to buy one. This much cheap­er and could be of inter­est of larg­er homes.

How­ev­er what if it is not pos­si­ble to deploy a wired LAN at home? There is also a solu­tion for that:

Wireless-only Network Setup

With­out a cable LAN one has to rely on pow­er line, mean­ing LAN over pow­er cables or use mul­ti­ple APs to extend the wire­less cov­er­age. A neat way of doing this is using a wire­less dis­tri­b­u­tion sys­tem (WDS). A WDS is work­ing like bridge at link lev­el, mean­ing that it is ful­ly trans­par­ent for the upper net­work pro­to­cols like TCP/IP or UDP. Deploy­ing a WDS is easy and is basi­cal­ly the same as using a wired back­bone, except there is none. The prob­lem aris­es if encryp­tion is turned on. In gen­er­al only unen­crypt­ed and WEP-encrypt­ed mode can be used in a WDS. This is usu­al­ly not an option. How­ev­er there are ven­dors that sup­port using WPA2 mode in their WDS, but you usu­al­ly can­not mix devices from dif­fer­ent ven­dors. I am using a WDS con­sist­ing of an Air­port Extreme and an Air­port Express and it is work­ing flaw­less­ly in WPA2 mode. The band­width of the wire­less con­nec­tion how­ev­er is halved as data has to be received and has to be resend to the client which means it is send over the air twice.

Tipps for Placing the Access Points

• Locate areas with weak sig­nal strength and add an addi­tion­al AP there if there is a cable back­bone. If there is none and a WDS is used place the AP such that it has still a good wire­less con­nec­tion to the home base.
• Use a net­work tool like KisMac to deter­mine which chan­nels are occu­pied by oth­er WLAN APs in the area. Sam­ple the whole area where the net­work should be to cov­er inter­fer­ences from dif­fer­ent neigh­bors. Use a free or less occu­pied chan­nel in the fre­quen­cy band. This is espe­cial­ly impor­tant for WDS as a fixed chan­nel has to be chosen.
• Use KisMac to mea­sure the sig­nal strength to improve the plac­ing of the APs and the direc­tion of the anten­na. This is best done with two peo­ple: one at the anten­na and one at the notebook.

Deploy­ing a WLAN in your home can be tricky if no prop­er tools are used. Using a net­work scan­ner such as KisMac and some time to exper­i­ment with the posi­tion­ing can pay off very well.