Published 4 November 2013
Wireless access points failing to connect
Or just intermittent or unreliable.
Due to the variety of so many different devices that may need to connect to a wireless network, sometimes it is impossible to connect certain devices, or the connection can be unreliable. Either way, to understand what is going on and what causes these connection issues is fundamental to being able to successfully resolve these connection issues to ensure your wireless network is configured correctly to work to its maximum capability; reliably.
Let us begin by taking two scenarios. Both different in nature but are caused by the same problem
A single access point, configured with a couple of computers connected and working along with a couple of mobile devices also connected and working. Someone brings in another laptop, or mobile device, and it won’t connect, or the connection keeps dropping.
There are multiple access points configured and working with a collection of computers and mobile devices. In addition, there are a few hand-held scanning devices operating in a warehouse that frequently loose connection.
What are the considerations?
Wireless Access Points have to be configured with the following 4 main considerations.
Wireless Channel – each access point needs to be on a channel that does not overlap. Overlapping channels causes interference and ultimately loss of data packet and loss of connection.
SSID – each access point on the same network needs to be configured with the same SSID, or wireless name. Multiple SSID’s require multiple profiles being configured on each device. Also SSID’s are case sensitive so it’s important to configure each access point with exactly the same SSID.
Encryption type – this one is probably the trickiest one to get right. Most devices support some level of encryption or security, and selecting the right one is paramount in being able to reliably connect each device.
Quantity of access points – less is more. It is important to be careful when installing wireless access points because having too many can be as bad as not enough. This is the time when you need to adopt an engineers’ approach and install the exact amount needed. Too many access points can cause interference with channel overlapping and also cause the devices connecting to switch between them more frequently than is required, which can cause data loss or temporary loss of wireless service.
When planning a new installation or troubleshooting an existing unreliable installation, it is important to first of all understand what the main function of the wireless network has to perform, i.e. is it more for mobile phone and laptop use or is it more for roaming scanners reading barcodes and such like.
If the network is more for laptops and mobile phones, work out where the heavier usage is likely to be within the building. There may be areas which aren’t so important to cover; users may be more inclined to sit at a laptop or a desk so therefore coverage would need to be in those areas. Use a plan of the building and mark on the plan where the centre of each hot spot would need to be to ensure coverage for that area.
If the network is more for mobile scanners in a warehouse, mark the entire area used for racking or where you are likely to be using the scanners. Examine the area in person to see what kind of stock is held within the warehouse, how dense is the material stored, is it likely to reduce the signal, see how high the stock is stacked, how much space is there above the racking and the ceiling. Also make a list of machinery being used and do some research on what electrical interference is generated by this machinery.
Identify the junction. Using your plan, see where the traffic flows around the location. Is there a central passageway, a thoroughfare, a collection point, a main office, a funnel, whatever you call it try and find a point on the plan where no matter how busy the building is, there is always activity there or the activity ultimately congregates there.
Choose your Access Points
Don’t just buy the cheapest or the most expensive. Do your homework, read the reviews and read the specification sheets. Selecting an Access Point which is designed to perform a particular function when you know what function your network has to perform has to be far better than just guesswork. Also, an access point you used previously may not always be suitable for a network that has an entirely different function, is in a different environment or has been installed some years before.
Detail your device list. Find out what devices you are trying to connect to the wireless network and make notes on the technical aspect of the device concerning the wireless connectivity. Do they connect using 802.11a, b, g, n, what encryption do they work best on? is it WEP, WPA, WPA2. WEP is a notoriously weak security standard, anyone with a laptop and basic knowledge could compromise the password in just a few minutes so if at all possible, avoid that one.
Match your Access Point to your network requirements. It’s not about buying the best wireless range; it’s about compatibility with your devices. There’s no point in buying an uprated wireless access point because the devices connecting to it have to transmit back to the access points for a 2-way connection to exist.
Unless you have a budget for a managed solution, positioning wireless access points and deciding on the number of access points ahead of installing your network is always going to require some careful planning in advance. Before fitting the access points in the chosen location, position them where you now think they should go based on your research to date and use a mobile scanner to analyse their performance. You can download a suitable app for most mobile phones that can work pretty well, it can tell you what channels your access points are working on, what overlap you have, the range and importantly what other wireless access networks are conflicting in your area.
Know your neighbours. If they are also using wireless technology, your scanner will be able to detect their network and you will be able to see how this interferes with yours. Configuring your wireless network to respect theirs will also serve you well when trying to achieve your own networks’ reliability.
Position your primary access point near to the higher traffic areas, or the area where most devices will pass. The chances are one access point will cover the entire requirements of most wireless activity without needing to switch over to another access point. The least amount of access point switching the better the reliability will be. If someone is frequently picking stock from one location and moving it to another, and during the transaction the mobile device switches access points despite the location being in an area that could in theory be covered by one access point, this is bad planning. Try and keep this within the range of one access point as much as possible.
Finally, know the IP addresses of each access point and its location. You may need to tweak some settings and having the correct information will help a lot when wanting to turn the odd one off when testing your changes. You should be able to install a reliable wireless network if you persevere with the set up. Avoid rushing in, take each step in turn, and give yourself plenty of time to think about each step before moving on.