Wireless Network Reliability
As technology advances, there has been a stronger push to increase portability. More devices are becoming solely dependent on wireless and mobile networks. What we need to ask is how dependable are these networks and is there enough infrastructure in place to handle the growing demand. With the increase of wireless networks being used around the world we have started to notice just how insecure these networks really are. There are new issues being discovered everyday with these networks. The first thing someone should know is that there is no such thing as a safe network whether its wired or wireless and a networks security risk greatly increases if that network is connected to the internet. So why are wireless networks being used for critical services such as ecommerce, or emergency response? We are purely relying on the wireless technology developers for providing us with the means to create and maintain secure, efficient networks. With the increase in demanding services we cannot stress enough the importance of reliability for the sake of sustaining this portable way of life. Throughout this paper we will talk about the several technologies available to the consumer and some of the known issues with each technology.
So, what is a wireless network? According to Cisco a Wi-Fi Network is “a wireless (LAN) that uses radio waves to connect devices such as laptops and mobile phones to the internet and to your business network and its applications.” The main purpose for wireless networks is to provide the end user with convenience, mobility, productivity, expandability, easy setup and cheaper cost. Through my own experience working for a school system in Cleveland I saw just how important it was to have a reliable wireless network. We had over 12 physical locations all connected as one network. We supported a google 1 to 1 program which provided every student 2nd – 12th grade with their own laptop that was used daily for accessing the online curriculum. On average we had over 5,000 devices connected wirelessly to our network. You can see immediately the importance of wireless technology as It would not be possible to support a program of this size without a wireless network in place. Using digital resources dramatically cuts costs and provided students with the added benefit of preparing students for their state issued online exams. Eventually all schools will be forced to provide their students with similar technology initiatives.
In this section I will discuss some of the different wireless standards along with the most common network topology that is used with wireless networks. The four most common Wi Fi technologies used are 802.11b, 802.11g, 802.11n, and 802.11ac. In the mobile phone world there are two main wireless technologies used CDMA and GSM. I have created a table to help distinguish the 802.11 family.
Standard Frequency Spectrum Speed Range Compatibility
802.11b 2.4Ghz DSSS 11Mbps ~300′ 802.11b
802.11g 2.4Ghz OFDM 54Mbps ~300′ 802.11b/g
802.11n 2.4Ghz (QAM) 100+ Mbps ~300′ 802.11b/g/n
802.11ac 5Ghz (QAM) Up to 1 Gbps ~300′ 802.11a
The most common topology used for wireless networks is the Star. The Star uses a central connection box typically a switch or wireless controller which connects the wireless access points to the router. I created a very generic network diagram to show what a Star Topology looks like.
It is also important that the proper management method is chosen for APs. There are two different types of access points the thick client and the thin client. Thick clients have to be configured individually. This is a very tedious job as it requires the network technician to connect through the console port or have a documented ip address for the specific device. Thin clients are easier to manage as they can all be seen and managed through the use of a wireless controller. However, each method presents its own security issues. Having to log into each device one at a time increases the risk of user error. The technician could easily forget to change the default login/password for the device leaving it open to attackers. Also, incorrect configuration could result in severe signal degradation or interference. Controller based clients are easier to configure and usually communicate with each other to choose the proper channels and signal strength. Finally, it is important to choose the proper wireless technology that will support your clients the best. Not all devices support 802.11ac and even though it uses the less crowded 5Ghz frequency there are some downfalls with signal strength. 802.11n is still the most widely used wireless standard.
Now let’s discuss how information travels over a wireless network. Any portable device has what’s called a wireless NIC. The NIC is responsible for converting data into radio waves which are then broadcasted to the AP/wireless router. The radio waves are then picked up by the antenna of AP/wireless router and are converted back to its original form. The best example to describe this communication is relating it to the human voice. The NIC speaks a language which is then received by the listener the AP/Wireless Router and finally transcribed back into its original language. Without some kind of encryption, the transmission sent wirelessly can be heard by any device within the range of the broadcast. The best ways to protect a wireless network is to have some form of authentication and encryption. Authentication is used for gaining access to the network, and encryption protects the transmissions sent between the mobile devices connected to the network. The four most common wireless security protocols are WEP, WPA, WPA2, WPA2 – enterprise.
Protocol Encryption Authentication
WPA RC4 – TKIP PSK
WPA2 TKIP – AES PSK
WPA2 – enterprise TKIP – AES AD – Radius
WEP is rarely used as it was the first security protocol developed. It can easily be cracked in under 1 minute. Hackers are able to crack WEP do to the size of the encryption key and the way key is updated. Even though WEP was said to have 64 – 128bit encryption keys RC4 encryption uses what’s called an initialization vector which stores 24bits of code. This means that the encryption part of WEP is actually only 40 – 104bit. The other issue with WEP is with its static encryption key that never changes from session to session. WPA was the first improvement of the WEP standard. One of the biggest changes with WPA is that it adopted dynamic encryption keys. WPA also offered a new integrity checker for encryption keys. The two most important upgrades added to WPA was the use of TKIP and a true 128bit encryption key. However, after a few years hackers eventually found ways to get around WPA. This brought about the most recent security standard WPA2 Personal and WPA2 Enterprise. The biggest change from WPA to WPA2 is the use of AES encryption which is way more robust and a lot harder to crack.