3/5/2013 – A recent security incident at Evernote allowed attackers... Read More
Are you having trouble with wireless networking?
This note from the Office of Information Technology may help. Wireless networking has come a very long way in the last ten years but so have the demands we are placing on it. With the proliferation of wireless devices and the increasing number of locations where WiFi services are offered, it’s easy to think that everything can and should be done wirelessly. In reality, however, it’s not quite that simple.
There are many factors that can affect your ability to get things done on-line when using a wireless network connection. To understand these factors, you need to have a basic picture of how it works. Your device (cell phone with WiFi enabled, tablet, or laptop computer) communicates with a Wireless Access Point (WAP) which is usually mounted in or on the ceiling somewhere nearby. The WAP is connected to the UA network with a traditional network cable connection (wired). The UA network provides Internet connection services and access to UA network applications. There are nearly 3,600 WAPs in service on the UA campus.
If too many users are trying to access one WAP at the same time, everyone’s network performance is diminished. The number of people that can successfully use the same WAP at the same time depends on what each person is doing. If one or more people are accessing streaming media or making Skype calls, for example, the wireless capacity (bandwidth) available to other users is greatly diminished. It is important to remember that a WAP provides less bandwidth than a hard-wired connection (i.e. a cable connection to a network wall jack) and that the bandwidth provided by a WAP is shared by all devices currently connected to it.
Sticky WAP Connections
The connection your device makes to a WAP is sticky. That means that as you move farther away from that WAP, your connection doesn’t necessarily change to another WAP that is closer. As long as it maintains a connection (even a poor one), your device will continue to use the WAP to which it originally connected. While this is a necessity of the WiFi technology, it can lead to overloading on some WAPs while nearby ones remain underutilized.
There may be a WAP located close to the door of a classroom, for example. People congregating in the hallway near the door may be connected to that WAP. Then as they enter the room, they may move closer to a WAP located within the room but their devices do not connect to it because of the sticky nature of the connection to the one by the door. The result is slower connections for everyone while the WAPs in the classroom are unused.
Idle Connections and Battery Life
Turning off your WiFi connection when not actually in use is an extra thing to remember but actually benefits you and others in a couple of ways. The WiFi radio in your device consumes quite a bit of battery power, even when you are not actually using it. It is constantly sending signals seeking a connection to a WAP. If there are WAPs within range, it says “Hi, I’m here” and the WAP responds with something like “okay, let me know if you need me.” This brief conversation happens over and over again as long as the device remains within range. While it doesn’t amount to much by itself, many devices in the same area all repeatedly carrying on with this handshaking conversation does place a load on the WAP. This diminishes the available bandwidth for devices that are actually trying to use the WAP. Leaving your WiFi on all the time is kind of like double-parking with your motor running. It blocks traffic and burns fuel unnecessarily.
Dead Spots and Interference
Even though we’ve tried very hard to provide good general WiFi service coverage to all buildings on campus and some outdoor spaces, there are still some gaps or dead spots. If you encounter one of these, please notify the IT Service Desk (348-5555 / firstname.lastname@example.org) and we will check it out.
Quite often we have found that a reported dead-spot is actually the result of radio interference. This can result from a number of things, all of which we discourage but cannot control:
- People using cellular hotspots (a feature of many cell phones that allows other nearby devices to connect to the Internet through the cell phones cellular connection).
- People using unsanctioned WiFi routers or hotspot appliances.
- Wireless printers or other devices operating in the 2.4GHz frequency band.
- Some microwave ovens, defective florescent light ballasts, or other devices emitting radio frequency noise.
- Some areas are architecturally constricted due to radio-absorbing materials or furnishings.