In this thesis we consider on Architecture of Voice over Long-Term Evolution (VoLTE) in Roaming networks with special consideration on IMS (IP Multimedia Subservice) core. The IMS core network of LTE architecture contains of three main parts. SBC, CSCF and TAS. Moreover, our job is testing and End 2 End troubleshooting among test cases that the company provided. This episode is called Laboratory level to test whole the cases that are anticipated and prepared by Vodafone which will be tested in live situation and if all the acquired results are as they are expected, the project will be implemented as a new technology for the clients.