How to setup a wireless network (WiFi)
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- Created on Wednesday, 27 June 2012 03:39
- Wireless framework obviously eliminates Wiring and Cables which gives us flexibility in positioning network devices around a Small Business office and cuts the wiring cost
- There are times when two or more office segments are separated by a street and WiFi can help one bridge the network without much hassle and investment
- Mobile devices of employees or visitors gain easy access to the Internet (hot-spot)
- WiFi Network Security: unless necessary precautions are mad e a malicious intruder can gain access to a wireless network and steal Internet Access, Data or launch an attack from your network shifting the blame onto your organization
- Distance limitations: depending on the amount of metal obstacles between a WiFi access point and a wireless adapter the strength of the signal can drop significantly. Without obstacles a good quality connection will stretch out to ~200-300 feet.
- Speed: currently 1GB Ethernet is roughly ten times faster than a Wireless network. If your organization often deals with massive data files (video, graphics, audio) the Wireless technology is probably not a good solution compared to 1G B/s data transfers
- Unlike mobile devices workstations would require a wireless adapter, same applies to network printers, etc (WiFi USB adapters are quite affordable though)
First let's touch base the very structure of WiFi communications (which is pretty straight-forward), that will give us enough knowledge on how to lay down the foundation to setup a wireless network. From the we'll discuss the radio Efficiency (optimizing the strength of the WiFi signal) and the aspects of Wireless Network Security.
Wireless Networks are constructed via Wireless Access Points: radio receivers and transmitters. An Access point is typically connected to a switch or a router. An AP is identified by its name - SSID - which is typically broadcasted and visible to mobile devices. In some cases an Access Point acts as a bridge or repeater between a central Access Point and a WiFi device in a remote area of an office. Ideally the main WiFi station should be located in the "center of mass" of all network devices in order to optimize the coverage by a high-quality radio signal. If the wired portion of the network has a 1GB capability it makes sense to ensure that the Access Point is connected via a 1GB link in order to avoid having a 100MB/s bottle neck between wireless devices and a server (data storage, etc)
This illustration presents a mixed scenario of application of WiFi technology.The central wireless Access Point is connected to an ISP's router in order to distribute Internet access. Let's say that the signal is strong enough to cover the main area of the office however the conference room is located a bit too far. This leads to the introduction of an additional component: Wireless Bridge- Repeater that extends the range of the WiFi coverage.
Generally it's unwise to let guests (or intruders?) gain access to the company network, especially servers. This is why it made sense to setup a Wireless Network solely dedicated to the reception area.
A detailed discussion on WiFi specifics would stretch too far and thus falls outside the scope of this article however we would like to introduce key WiFi concepts which can be easily looked up in depth via Google .
WiFi Signal strength and ways to strengthen it
The magnitude of the WiFi signal defines the speed of data transfer and the link quality (which determines the portion of transmission errors requiring additional traffic for corrections). In other words we want to maximize the signal and optimize the reception. This is usually archived by means of:- Optimizing the relative positioning of the Access point and a receiver: the more obstacles we have en-route of a radio wave - the worse it gets for the signal to travel. In real life it translates into a simple strategy of keeping WiFi devices somewhat elevated in order to eliminate screening by furniture (desks, drawers, chairs, etc). Of course it's important not to block the wave path by a computer case itself or a monitor.
- Antenna orientation: it's best to keep the transmitting and receiving antennas aligned. Typically there are many receivers and it's impossible for a sole transmitting antenna to suit all of them. This can be resolved by the introduction of multiple antennas on the transmitter side. Two or three antennas operate at independent orientations allowing for the optimization of the signal strength among numerous receivers.
- The power of the transmitter: a rather straight-forward method of simply increasing the power of the transmitting radio of the Access Point, for example boosting a typical strength of 2dBi to 9dBi. It only works on sending signal out whereas the wireless adapters keep their own power and thus receiving data back from WiFi devices is still in trouble unless a high-gain directional antenna is used. It's worth mentioning here that this is the best way to network two offices separated by a considerable distance but still within the line of site.
- Dual-band provides separation of frequencies at which different generations of WiFi operate: 2.4GHz used by B, G, N 802.11 protocols and 5GHz used by A and N. Independent frequencies eliminate interference and provide "space" for more concurrent transmissions.
Extending the WiFi area
There are several ways to achieve this task varying in cost and complexity of a wireless network setup. Again, we'll introduce the main three without getting too deep into technicalities.WiFi Repeater - essentially it's just a Wireless client that creates its own network with a stand-alone SSID and subnet (hence the term "repeater" is a bit misleading)
WiFi Bridge-Repeater - in this case the name should be understood verbatim: a bridge-repeater extends the wireless network while acting as a bridge and thus its clients perceive the extended network just like their peers connected to the main Access point.
WiFi Mesh layout - it's a hybrid scenario in which multiple Access Points are connected at different nodes of a wired network and represent the same subnet, SSID.Security
The security of WiFi communications is a very extensive and complicated topic. Prior to deciding to setup a wireless network it's important to define the level of desired protection because it could necessitate a wide range of defence mechanisms. Here we would merely list the primary protection layers which are discussed more thoroughly in the article dedicated to Wireless Security.- Hidden SSID - only folks informed of the existence of such Wireless Network would be able to connect. Protection Strength: weak because a hidden SSID can be intercepted with the right tools
- MAC address filtering - only computers with registered MAC addresses (`unique` identifiers of their network adapters) can connect to a Hot-Spot. Protection Strength: weak because a MAC address can be intercepted and forged
- Password authentication and Encryption - a client must provide a password in order to connect, all traffic is encrypted. Protection Strength: medium to strong depending on the type and complexity of the authentication and encryption - WEP, WPA, WPA2.
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