VoFi stands for Voice over Wi-Fi. Whenever you use your VoIP connection over a wireless connection, you are using VoFI. Do you have people connecting to the network via Wi-Fi connection and then using a soft phone to make a call? Then you are using VoFi.

For a few people, a regular data Wi-Fi connection works fine, but when you are planning on rolling out VoFI for a large number of people, a shared data Wi-Fi connection will not work.

To successfully use a Wi-Fi connection you need to make sure your corporate wireless connection has high bandwidth to host voice connections, low lag times and fewer hops. You may need a higher number of access points if you plan on using voice over the connection compared to plain data.

You can get away with using VLANs on same access points, some companies go a step further and setup a totally separate network for voice. Normally if a company is using 802.11b/g for data, they might want to consider using 802.11a for voice since they use different frequencies and this minimizes any chance of interference.

The best thing you can do is to perform an extensive and comprehensive wireless survey before rolling out VoFI. Take care of all the problem zones and if at all possible have a separate Wi-Fi infrastructure for voice side. Using a 802.11a connection would be better for voice and/or video since this standard offers more bandwidth and is less interference prone compared to the 802.11b/g standard.