The long pole(s) in the tent for VoLTE roaming is complex and convoluted. Further, there is nothing close to universal agreement between the leading operators, 3GPP and the GSMA regarding how to address these challenges. As we discuss in this report, VoLTE / VoLTE roaming introduces a number of new nodes and interfaces within IMS. Further, there is a fair amount of flexibility regarding how operators implement VoLTE / IMS and this flexibility leads to additional interoperability issues between the VoLTE clients and each operator’s VoLTE / IMS configuration.
WE DISCUSS THE FOLLOWING:
- VoLTE / IMS introduces several new nodes and interfaces. The combination of these changes and the flexibility that operators have when it comes to implementing them creates interoperability challenges, both between operator networks and between VoLTE clients and each operator’s VoLTE implementation.
- There are presently 4 network architectures that operators can use to enable VoLTE roaming and, unfortunately, leading operators are divided regarding which approach should be used. At least a few influential operators are advocating an architecture that is relatively simplistic to implement and achieve interoperability. However, the tradeoffs are fairly substantial and we are less than convinced that it is the right approach.
- Ultimately, whatever network architecture the operators select, it is one that ALL operators will need to adopt and they will need to live with it for the next 25 years.