As of April 2025, the global landscape of Voice over LTE (VoLTE) roaming agreements has expanded significantly, reflecting the industry’s shift towards all-IP voice services and decommissioning legacy 2G/3G networks. Global VoLTE Roaming Agreements According to the GSMA, over 900 VoLTE roaming agreements have been established worldwide. These agreements involve more than 250 mobile network operators across approximately […]

When going to the Roaming topic, sometimes you hear words like Wholesale Charge and Retail Charge. So What is the difference between them? The Wholesale Charge determines how much roaming costs a mobile operator. Here, mobile operators negotiate roaming agreements with their counterparts in other countries. Under these agreements, a mobile operator pays the foreign operator […]

The 3rd Generation Partnership Project (3GPP) architecture has introduced a subsystem known as the IP Multimedia Subsystem (IMS) as an addition to the Packet-Switched (PS) domain. IMS supports new, IP-based multimedia services as well as interoperability with traditional telephony services. Voice Over LTE (VoLTE) is the technology to provide Voice service over LTE, However, not […]

Recently, I received many questions and inquiries about the meaning of Roaming and some interesting questions: What is Roaming? What is the difference between National Roaming and International Roaming? First, all of us know that mobile communication networks and services have become an integral part of everyday life. People are now more and more reliant […]

The Security Edge Protection Proxy (SEPP) is a proxy that sits at the perimeter of the PLMN network and enables secured communication between inter-PLMN network messages. It protects the home network and acts as a security gateway. Located at the edge of the network, it polices connections between the home network and the visited networks. […]