M3UA

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.

Several AS owns PC itself and uses SGW as STP (transit pointcode).

[1] Wireshark is shipped with a dissector for M3UA, sample packets can be found in Wireshark's wiki page, which shows ISUP Packet samples (including M3UA[2]).

Point code ISUP SCCP MTP-3 MTP-2 MTP-1 Point code MTP-3 MTP-2 MTP-1 M3UA SCTP IP L2 L1 Point code M3UA SCTP IP L2 L1 ISDN Signaling gateway Media Gateway Controller
M3UA: Transmitting MTP-3 messages: on the left is the TDM -network for SS7. On the right is the IP network with SIGTRAN as a transport.