TE (VoLTE) also comes with its own stringent requirements for minimal latency of voice packets, which may imply that even within services offered to the same user, voice may need to be given higher priority than pending data packets for the user. Normally, such complex conditions are met by implementation of scheduling algorithms that support guaranteed bit rate services such as the proportional fair scheduler (PFS), for example, but the implementation and testing of such solutions gets even more complicated with multiple users with differentiated priorities, classes, and services. There are more solutions for implementing VoLTE support using existing IP multimedia subsystem (IMS) based core networks, which uses single radio voice call continuity (SRVCC) to address voice requirements. The IMS is used to control the handoff of the user to legacy networks that support voice. Thus, the operator needs to plan the solution with IMS support in mind when starting deployment. Multivendor Interoperability The original goals for LTE when the standardization efforts were made was to make standards in such a way that network elements from different vendors can interoperate seamlessly. Such a solution would give operators the benefit of being able to mix and match network elements as they desire to give them competitive advantage and prevent overdependence on any particular vendor implementation. This would have allowed operators to be able to negotiate price and services and also allows for the market to possibly gravitate toward the best performing network elements for appropriate functions. Reality, as usual, is painting a different picture. It has been found that interoperability is not ensured between equipment from different vendors. In most cases, extensive testing is needed to conform that equipment and solutions are interoperable. Although the early entrant to the market has an advantage in terms of being the default implementation to which the later vendor needs to comply, the fact remains that true multivendor inte