WiFi – Standards, Routers and WiFi Security Explained

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WiFi

WiFi is a wireless networking technology that uses radio waves to provide high speed. A common misconception is that, the term Wi-Fi is short for “Wireless Fidelity,”. What added to the confusion was, the Wi-Fi Alliance’s use of an advertising slogan, “The Standard for Wireless Fidelity,” which lead many people to think that Wi-Fi was an abbreviation of “Wireless Fidelity”. Wifi Generally uses Radio Frequencies of 2.4 Ghz or 5 Ghz.

WiFi Standards

Standard for wifi network is 802.11 that is created and maintained by IEEE

  • 802.11a – IEEE expanded on the original 802.11 and created 802.11a. The 802.11a uses frequencies of 5 Ghz and has a maximum speed of 54 Mbps. Since it has a larger frequency, it couldnt cover larger distance.
  • 802.11b – 802.11b was created at the same time as that of 802.11a and It is not the next version of 802.11a. It works on 2.4 Ghz range. It has a maximum speed of 11 Mbps. Because of smaller frequency, it get better range than 802.11a. But the problem is that, there are so many devices like microwave oven, baby monitor, bluetooth devices, that are working on the same frequency that can cause interference with our wifi signals.
  • 802.11g was an upgrade to 802.11b. This operates in 2.4 Ghz and It can have maximum speed of 54 Mbps. It is backward compatible to 802.11b
  • 802.11n upgrade was made to bring together 802.11g, 802.11b and 802.11a. It can operate at 5 Ghz and/or 2.4 Ghz simultaniously. It can have maximum speed of 450 Mbps. It uses Multiple Input Multiple Output technology.
  • 802.11ac-Operates in 5 Ghz band. It has a denser signalling modulation, which helps us for faster data transmission. It can have maximum speed of Nearly 1300 mbps.

Wireless Router

A wireless router is a device that is used to provide wireless access to the Internet or a private computer network to wifi enabled devices.

Inside a WiFi router, there are mainly 3 discrete components

  • The Router
  • Network Switch
  • Wireless Access Point

Router is the Traffic controller between your home network and the public network
Network Switch is the Traffic controller between all the device with in our private network or LAN
Wireless Access Point or AP is Radio with antenna which acts like a mini cell tower that communicates with all the wireless devices over the approved frequesncies, usually in 2.4 and 5 Ghz

Multi Band Routers and Increased Bandwidth

Wifi devices can only process one request at a time. So if there are multiple devices using the same wifi connection in a given channel or frequencies, the packets may come at the same time and it may collapse. Or we say that a collision has occurred. WiFi gets around this issue by using a technique called CSMA-CA or carrier sense multiple access with collision avoidance.

CSMA CA

Here the Access point checks wether the channel is busy before sending a packet. If the channel is not in use, it will send the packets from source to destination. if the channel is busy, the AP waits for a random amount of time before attempting to retransmit again.

If node has a packet to send, node senses the channel status. If channel is busy, a back off timer will be started and wait for a random time. After that it senses the channel again. Now if the channel is free, it will send the packet, if not the whole thing will be repeated again.

This random time is called back off time. This time is one of the reason slowing down the datarate of the wireless routers.
In the case of dualband or triband routers, even though if one channel is busy with a device, there are other channels available which can send or receive data from other device. that is why dualband and triband APs are much faster than single band access points.

WiFi Security

Now a days, every offices, houses, hotels, parks, hospitals, almost everywhere there is wifi.
But the real question is, are they secure?If your wireless access point is not properly secured, people from other houses, offices or nearby buildings can gain access to it.
People who are able to connect to your wireless router or network, may be able to

  • Monitor all the websites that you visit
  • Log your usernames and passwords
  • Read all your emails as they travel through the network
  • Slow down your computer or laptop and the Internet connection speed
  • Perform illegal activities using your Internet connection or even
  • Spread a virus or a worm to all devices in the network

In order prevent these attacks and stop unauthorized access, there are certain security measures adopted.

WEP

WEP stands for Wired Equivalent Privacy. Main purpoes of WEP was to bring the security of a wired connection to the world of wireless communication. for WEP there are different kinds of encryption available – a 64 bit key or a 128 bit key depending up on the implementation type of your network.

But there are some limits for wep. WEP is not recommended for a secure wireless Network. There are so many cryptographic vulnerabilites in encrypting and decrypting the data. The initialization vector that is used in the encryption process, which is supposed to be totally random, is only 24 bits long. The main security risk is that people capturing the encrypted packets , can crack WEP encryption in a matter of minutes.

WPA

The successor of WEP is something called WPA. WPA stands for Wifi protected access. Here the  Initialization vector is longer than that of WEP. Here another method of ciphering the information using the RC4 cipher and an integrity protocol called TKIP of Temporal Key Integrity Protocol is used.

Each packet transmitted using TKIP has a unique 48-bit serial number that is incremented every time a new packet is transmitted and used both as the Initialization Vector and part of the key. Putting a sequence number into the key ensures that the key is different for every packet. WPA is backward compatible which means WPA can be used on the same hardware that supported WEP. We just have to upgrade the software for that.

WPA II

WPA2 is the next version of WPA. WPA2 replaced RC4 with a more advanced method of encryption called AES or Advanced Encryption Standard. This also replaced TKIP with another protocol called CCMP which is much more stronger than TKIP and it can make sure that data within the packet is exactly where it came from.

WPA II Enterprise

WPA2 Enterpirse is the most secure method of Wifi connection. It is done by integrating WPA2 with Radius Server Here, you can use your standard username and password to gain access to you wireless network.

Secure Your WiFi Network

  • Always use WPA2 security rather than wep
  • Use a password that contains alphabets, numbers and special charecters greater than 10 digits
  • Disable wps
  • Hide you network by Disabling broadcast of ESSID
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