Overview
VoIP or Voice over IP technology is a combination of hardware and software, which allows users to make telephone calls using the Internet as a transmission medium. Wireless technology allows the users to transfer information without the use of wires. Wireless VoIP (Voice over Wireless fidelity or VoWiFi) is a wireless based IP system that is designed to work on wireless devices like laptops or Personal Digital Assistants (PDA).
VoWiFi offers the suitable features of VoIP technology, yet it will give users the mobility of a cordless phone.
Today's Wireless products provide 11 Mbps data transfer rates that meet most of the requirement of today’s application and are mostly 802.11b standard. Some vendors also support 802.11g and 802.11a standards (also known as A and G standards), which provides data transfer rates of 54 Mbps or higher.
How it works
Wi-Fi phones or Dual-mode cell phones contain both a Wi-Fi and a regular cellular radio. The Wi-Fi radio is used to connect the cell phones to a wireless Internet network through a wireless router.
• When the Wi-Fi phone is within a range of wireless networks, the phone automatically connects and recognizes the wireless network.
• All the calls that you make on the wireless network are routed as VoIP calls through the Internet.
• If the phone is not in a range of wireless networks, it automatically changes to the standard cellular network, and calls are charged as usual.
• Wi-Fi phones can hand off flawlessly from cellular to Wi-Fi (and Wi-Fi to cellular) in between the call as you exit and enter the wireless networks.
Security
VoWiFi required three levels of security for –
1. Voice transmission.
2. Control signaling function and configuration.
3. Wireless LAN (WLAN) or Wireless routers.
Current generation of Wireless hardware (WLAN or routers) uses Wired Equivalent Policy (WEP) and encryption of information or data between a client and an Access Point as the security mechanism for the wireless networks to validate the user. WEP does not provide a key exchange mechanism and therefore, it is not implemented in most of the cases. Instead of WEP, AES (Advanced Encryption Standard) is used as a security mechanism.
Problems faced with VoWiFi
• VoWiFi is deployed mostly in corporate or enterprises rather than houses.
• QoS (Quality of Service) is not good as with wired networks.
• Set up and maintenance cost for wireless network is high as compared to wired networks.
• The potential security threats are more natural in wireless networks.
• Signal degradation is another problem when a user is not in the home network i.e. during roaming.