Bandwidth is the rate of data transfer which your Internet service provider enables. In order to have a quality hosted VoIP call, you need to have an Internet connection which supports the data transfer. Some services offer a specialized connection to provide reassurance that the data will be transferred at an optimal rate. Other providers allow you the luxury of choosing your own Internet Service Provider. While there are pros and cons to either decision, when considering case of call quality, you must ensure that you choose an Internet service which supports the data transfer which your hosted VoIP PBX demands.