Frequently Asked Questions
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What are the advantages of a controller-based wireless network? As a basic rule-of-thumb, if you are going to need more than 10 access points, you should consider a controller-based wireless network as opposed to a autonomous access point infrastructure. Controller-based wireless networks have the following benefits: Better Security – Access points must conform to a set security policy to be part of the network Improved Roaming – A controller-based wireless network can track users and handle roaming functions from a centralised point. This means that users do not need to re-authenticate when moving from one wireless coverage area to another. Expandability – Additional access points can be added to the network more easily without substantial configuration changes. Easier Administration – Centralised software or firmware management for wireless access points makes it easier to make changes to your wireless network. Power over Ethernet Support – The ability to reboot APs from a central location saves the network administrator from having to physically visit each wireless AP for configuration or maintenance purposes. Load Balancing – One of the key benefits of a wireless controller is load balancing. A load balanced network means that user demand is spread out evenly throughout the network of wireless access points. This means no single AP is over-strained and data throughput rates are optimised. Quality of Service Management – QoS is an extremely useful function for prioritising data traffic. When QoS is centralised, it results in easier administration. |
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We have 15 users and I need a wireless controller solution that is reliable, secure and high-performing. What should I be looking for?
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On a Windows 2008 server, I can access shared folders perfectly via Ethernet cable but not when I use my laptop connected via wireless LAN? This is usually caused by either your software or hardware firewall. Temporarily disable all firewalls and try to access the shared folders again. Then, if you can successfully access the folders with firewalls disabled, the problem can be solved by changing the permissions on your firewall. |
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We all use Macs in our office. However, there is one Mac that will not accept the network password, even though all the other Macs in the house connect perfectly well? Assuming you’re definitely using the right password, the most likely problem is a corrupted “plist” folder, and deleting this should solve the problem. You will find it in the folder path Mac HD / Library/Preferences / System Preferences. |
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We all use Macs in our office. However, there is one Mac that will not accept the network password, even though all the other Macs in the house connect perfectly well? Assuming you’re definitely using the right password, the most likely problem is a corrupted “plist” folder, and deleting this should solve the problem. You will find it in the folder path Mac HD / Library/Preferences / System Preferences. |
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I have an ancient Mac G4 which I need to connect to a wireless network. The USB dongle which I bought from a computer store does not support Mac drivers. How do I connect it to the internet? Use a wireless bridge. It plugs into the Ethernet port of your Mac and lets the G4 ignore the wireless aspect. The bridge will wirelessly relay all traffic from the G4 to your main router without the Mac ever being the wiser. |
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We want to limit the amount of users on our wireless network at any one time to just 10 users. Can this be achieved? Yes, this can easily be achieved by setting the maximum number of IP leases on your router or access point to 10. If an eleventh user tries to login, they will be disallowed. |
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In our office, when using Skype, sometimes the quality of the connection can be very poor. However, internet browsing works perfectly. The router is a high specification 5Ghz model and I suspect this should not be happening? When voice is carried in the form of data packets, they must be transmitted at a constant rate to be intelligible. By contrast, if you are downloading a data file, if your wireless network is busy and the download takes 2-3 minutes extra, it is not usually an issue for people. However, this becomes an issue with a VoIP application like Skype, where delayed data packets can result in a garbled or interrupted VoIP session. To mitigate against this, most manufacturers of quality routers have included a feature known as “QoS” (Quality of Service) on their devices. QoS is a feature which allows you to give each type of traffic a guaranteed percentage of bandwidth. In this case, you would need to login to your router, access the QoS settings and give VoIP priority. When VoIP traffic has been prioritised on your network, Skype sessions should become a lot smoother. |
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In our open plan office, we have one single antenna wireless router. We have much of the floor space covered wirelessly but there are some dead zones? Each office will have a unique wireless setup. Dead zones or dead spots occur due to object interference, RF interference or busy wireless channels. One quick way to eliminate dead spots is to make sure you have some antenna diversity in your office. If the wireless router you are using only has one antenna, think about adding a second one. Antenna diversity means that, if one wireless station cannot pick up a good quality signal from one antenna, the chances of a good reception are improved if a second antenna pointing at a slightly different angle is used. |
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We have 4 iPads in our office and our main access point is a Cisco 4400. When we try to use the Airprint feature, it is not detecting the Epson printer. However, when I try to connect the printer using a D-link access point, I can use Airprint straight away? Wireless printers sent out multi-cast signals to their coverage area. (Basically, this is a signal communicating “I am here, I am ready to be connected”). Usually, when you have one access point that cannot communicate with a printer, the problem is probably caused by the Multicast feature being disabled. Enable Multicast on your Cisco access point and it should detect your printer then. |
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We have a wireless TV in our living room. Occasionally, during video playback the picture can get very choppy. However, when using a laptop in the same room, streaming video playback is always perfect? A quality wireless connection is usually dependent on 4 key factors. These include: Distance between the AP and client – In general, the longer the distance the weaker the signal. Power – The power level at which the AP and wireless client are transmitting at. RF Interference – The level of interference from neighbouring AP’s and other electronic devices. Object Interference - Physical obstacles such as walls, doors etc., which cause signal attenuation. When streaming video over wireless, the wireless client, in this case the TV, buffers the wireless packets. If for any reason, the wireless link is attenuated by any of the four factors as mentioned above, the TV runs out of buffer and the user will notice a lag. The reason why your laptop does not experience this lag is because computers have a much greater buffering facility than your standard internet-enabled TV. To resolve this problem, you could change the location of the AP relative to the TV i.e. bring the AP closer to the TV. Alternatively, you could try change the channel of the AP to a less busy one. |
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Are wireless networks insecure to use? Public hotspots typically have no security at all; if they do, it’s a shared password that provides no protection from other people on the network. When you connect to a public wireless network, we recommend you only use secured services or a virtual private network connection. On the other hand, Wi-Fi at home or at work will likely remain safe as long as you have secured the network with WPA2 Personal or WPA2 Entreprise. If your office handles extremely sensitive data, you should opt for WPA2 Entreprise encryption because it allows individual usernames to be assigned for network access. This access can be tracked and revoked. WPA2 Entreprise is an instance of 802.1X port-based authentication, which can be used with Ethernet and older Wi-Fi standards. All variants of the 802.1X standard let you connect in a limited fashion to the network. It is only when user credentials are verified against a central server or radius server that users get full access. (This two factor authentication is usually setup by installing a digital certification on users’ devices). |
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The wireless access points in my home all work with DHCP. However, after rebooting the devices, they all resort back to their default IP address. How do I solve this? This is most probably caused by a DHCP timeout issue. When you access the settings of the AP, you should be presented with an option of DHCP timeout from 0 to 3600 seconds. This tells you how long the AP waits for a response from a DHCP server before using a static IP. Setting a timeout period of 0 means the AP will get its network settings from DHCP permanently and will not seek out an alternate static IP address. |
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I recently reset my router. Now, I cannot use MSN chat and shared printers no longer work? This is usually symptomatic of UPnP (universal plug and play) being disabled on your router. Log in to your router’s administration panel and enable UPnP. |
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We have a simple wireless network setup in our office. How can I tell which devices are connected to it?
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We have 15 Wireless G access points in our hotel. They are set to 3 channels to minimise overlap. Is there anything else I can do to further reduce co-interference? You can reduce the power of each access point to minimise wireless bleeding from one wireless coverage zone into the next. It might also be a good idea to keep a 20dB difference between channels. For example, if you have two access points on channel 1, you should set one access point to 50dB and the other to 70dB. |
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We are a not-for-profit organisation. Some of our users are still using older type laptops and while the office wireless network works, it is not very fast? Without a site survey, it is impossible to answer this question with any reasonable degree of accuracy, but one point you have mentioned sticks out. You mentioned that some users are using older type laptops. It would be our guess that these are still using wireless G. As a result, the speed of the wireless network is “dropping down” to accommodate these devices. One solution would be to upgrade the wireless cards of these devices to wireless N cards. This would mean the network will operate at minimum wireless N speeds or higher, instead of wireless G. |
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Some of the wireless devices in my office cannot pick up any wireless signal. When I go to type in “ipconfig” to get the network information, the wrong networking information seems to appear? This is usually indicative of a rogue access point or rouge DHCP server being present on the network that is giving out wrong information to the wireless clients. You need to trace this device and remove it from your network. For example, look out for any additional routers on the network, bearing in mind that a lot of routers can physically resemble a hub or switch. |
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I am the ICT co-ordinator in our school. On each floor we have a standard Linksys access point but sometimes when we have up to 25 laptops logging on at the same time to the same device. When this happens, internet access seems to freeze or be very slow? Your school would probably benefit from a centrally managed wireless controller to get optimal performance from your wireless network. However, as an interim measure until you upgrade your equipment, you could give neighbouring access points in your school the same SSIDs and passwords. When you acquire a wireless controller, it will intelligently manage traffic. If one AP is extremely busy or getting overloaded, the central controller will redirect traffic to a less busy access point. In addition, a wireless controller will give you:
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