The M3UA protocol is a communication protocol of the SIGTRAN family, used in mobile telecommunications networks to carry signaling over Internet Protocol (IP). M3UA enables the SS7 protocol’s User Parts (e.g. ISUP, SCCP and TUP) to run over virtually any network technology breaking its limitation to telephony equipment like T-carrier, E-carrier or Asynchronous Transfer Mode (ATM), which highly improves scalability of the signaling networks. M3UA stands for MTP Level 3 (MTP3) User Adaptation Layer as defined by the IETF SIGTRAN working group in RFC 4666 (which replaces and supersedes RFC 3332). Like other adaptation protocols, M3UA uses SCTP to transmit messages between its network elements.
Some of the common use cases of the M3UA protocol in mobile telecommunications networks are:
- IP Signaling Point (IPSP): This is a model where M3UA nodes are connected directly to each other over IP, without the need of a signaling gateway. This allows the nodes to exchange SS7 messages and data directly, using their own point codes and routing tables. This model is suitable for networks that have migrated fully to IP, or for networks that want to interconnect with other IP networks.
- Application Server (AS): This is a model where M3UA nodes are connected to a signaling gateway (SG) over IP, and the SG is connected to the SS7 network over TDM or ATM. This allows the nodes to access the SS7 services and features, such as number translation, local number portability, prepaid billing, and others, using the SG as a transit point. This model is suitable for networks that have not migrated fully to IP, or for networks that want to interconnect with legacy SS7 networks.
- Signaling Gateway (SG): This is a node that acts as an interface between the IP and SS7 networks. It implements both the M3UA and the SS7 stacks, and performs the adaptation and translation of messages and data between the two networks. It also maintains the point codes and routing tables for both networks, and handles the load balancing and congestion control. An SG can serve multiple M3UA nodes and SS7 nodes, and can support multiple signaling links and associations.
These are some of the main use cases and functions of the M3UA protocol in mobile telecommunications networks. The M3UA protocol enables the integration and interoperability of IP and SS7 networks, and provides a reliable and efficient transport mechanism for SS7 signaling messages and data.
