What is VoIP Billing? There are so many service providers are doing billing based on the services they are providing to their customers. All the parameters are simple enough to charge a customer for the provided services. Billing solutions also provides many other features such as calling cards, least cost routing (LCR), did management, resellers management etc. What is Class 4 and Class 5 Softswitch? In simple term, Class 4 softswitches route traffic between different Class 5 areas. One way to think about it is this: a Class 5 softswitch is a retail solution while a Class 4 softswitch is