How to deploy a Wi-Fi network?

Wi-Fi network deployment is not a trivial task and should not be performed without thorough analysis and planning. Here are some tips:


1. Site Survey
The location should be surveyed to find out the area and number of floors to be covered. Bear in mind that ceiling, wall and flooring thickness and materials could affect propagation of Wi-Fi signals.

 

2. Channel selection
Use AP Discovery (Wireless LAN >> AP Discovery) and Interference Monitor (Diagnostics >> Interference Monitor) on the access point or router to identify the channel with the strongest signal and the least amount of congestion. For more information on these features, please refer to the application notes How to use AP Discovery? and What is Interference Monitor and how to use it? 

In addition, there are mobile apps available from iTunes and Google Play stores that can assist in the analysis of the Wi-Fi spectrum:

  • Wi-Fi Analyzer
  • InSSIDer

 

3. AP location selection
You can use the AP Map feature (Central Management >> AP >> AP Map) to determine the optimal locations to install access points on your premises. For more information on AP Map, please refer to the application note How to plan the wireless coverage by using AP Map feature on AP Management (APM) before we deploy the VigorAPs? 

It is recommended that access points have 15 to 20% overlapping coverage to ensure adequate overall coverage.

4. Understand the effects of signal strength, propagation and barriers
The ability of wireless networking devices to penetrate barriers depends on several factors:

  • The power of the signal from the transmitter. IEEE 802.11 mandates that the maximum transmitting power of wireless devices be 20 dBm, or 100 mW. As a general rule, stronger signals are better at penetrating barriers such as walls and floors.
  • The sensitivity of the receiver. Currently the most sensitive wireless device has a reception sensitivity of -105 dB. The lower this value is, the more sensitive the device is at receiving weak signals.
  • Obstacles. Try to avoid barriers by relocating access points, as wireless signals degrade when they have to pass through barriers such as walls, furniture, and floors.

    Examples of some common indoor obstacles and their rates of wireless signal absorption:
Material Absorption rate Examples
Wood panels Low Inside walls
Gypsum boards Low Drywalls
Fabric Low Furniture, cubicle partitions, curtains
Clear glass Low Windows
Tinted glass Medium Exterior windows
Concrete Medium to High Walls
Mirrors High Glass mirrors
Metals High Metal furniture, metal doors
  • Antenna gain. The standard antennas supplied with most WLAN devices have a gain around 2dBi. If the signal is to be passed through multiple walls, the antennas should have a higher gain, ideally between 3 to 5 dBi. VigorAP (except AP910C) that have replaceable antennas are more flexible as you can easily replace them with higher gain or external antennas if the supplied ones are not adequate.

 

5. Consider enabling Wi-Fi roaming to provide users with a better online experience. Wi-Fi roaming lets wireless clients roam between different access points within a network with minimal service disruption to provide seamless connectivity. For more information on Wi-Fi roaming, see the application notes What is wireless roaming? and What is AP-assisted Client Roaming?

 

6. Each frequency band on a Vigor AP can support a maximum of 64 MAC addresses at any given time. (AP920R could afford up to 128 MAC address per band). Additional access points might be required depending on the number of wireless clients that will be online simultaneously. Enable AP Load Balance to evenly distribute network load across multiple APs. See application note What is AP Load Balance? for more information on AP Load Balance.

 

7. For dual band wireless model, we could also enable the band steering for 2.4GHz with the less congested. At the same time dual band client will be encouraged to connect to 5GHz wireless which is faster. See application What is Band Steering? for more information.


8. Consider segregating APs by usage to maintain security and performance. For example, visitors and employees can be placed on separate APs. See application note How to separate the Wi-Fi access for guests and employees with Vigor3900 and VigorAP 900? for more information about client isolation by SSID and VLAN.

 

9. For efficient and effective management of multiple access points, use DrayTek’s Central AP Management. See application notes Introduction of DrayTek AP Management (APM) Solutions and What is Central AP Management (APM) and how to enable it? for details.

 

10. Vigor routers provide a feature called Hotspot Web Portal that can be used to authenticate wireless users or get them to agree to terms of service that are shown on a landing page. See application note What is Central AP Management (APM) and how to enable it? for details.

 

11. If you experience difficulties with wireless performance, see this application note for assistance: How to improve Wi-Fi performance?

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