SIGTRAN protocol description

The SIGTRAN protocol is one of the important protocols in signaling transmission. Now we will give a brief introduction to this Protocol. First, let's take a look at the basic concepts of this Protocol. The SIGTRAN protocol is a set of transmission control protocols established by the IETF signaling Transfer Working Group SIGTRAN protocol to transmit PSTN signaling over an IP network. SIGTRAN defines a complete SIGTRAN protocol stack, it can be divided into four layers: IP protocol, signaling transmission, signaling transmission adaptation, and signaling application. The content of each layer is as follows:

◆ IP protocol layer: IP

◆ Signaling transport layer: SCTP

◆ Signaling transmission Adaptation Layer: SUA; M3UA; M2UA/M2PA; IUA

◆ Signaling Application Layer: TCAP; TUP; ISUP; SCCP; MTP3; Q931/QSIG

Different signaling application layers require different signaling transport adaptation layers, but the IP protocol layer and the signaling transport layer are shared and the same. the correspondence between the signaling transport adaptation layer and the signaling application layer is as follows:

◆ SUA corresponds to TCAP

◆ M3UA corresponds to TUP; ISUP; SCCP, TCAP

◆ M2UA/M2PA corresponds to MTP3 and ISUP

◆ Q931/QSIG and ISUP for IUA

(1) SCTP Protocol

Proposed by IETF, SCTP is a connection-oriented transport layer protocol that uses traffic control and congestion control algorithms similar to TCP, this mechanism ensures reliable transmission of user data between two SCTP endpoints. Compared with other transmission protocols such as TCP, SCTP has a low transmission latency, it can avoid the blocking of some big data on other data and provide higher reliability and security ｡

(2) M3UA Protocol

M3UA is the third-level user adaptation layer protocol of MTP, which provides the signaling point encoding and IP address conversion. It is used to transmit the No. 7 signaling protocol between the softswitch and the signaling gateway, MTP third-level user messages, including ISUP, TUP, and SCCP messages, can be sent transparently by M3UA as the net load of SCCP messages ｡

(3) M2UA/M2PA Protocol

M2UA/M2PA is the second-level user peer-to-peer Adaptation Layer Protocol of MTP ｡

(4) IUA Protocol

IUA is the user adaptation layer protocol of ISDN Q.931 ｡

(5) SUA Protocol

SUA is a SCCP user adaptation layer protocol. Unlike M3UA, SUA directly implements the TCAP over IP function ｡

The SIGTRAN protocol supports standard primitive interfaces for PSTN signaling applications and uses the standard IP Transport Protocol as the low-layer transport signaling. It is one of the important transmission control protocols in NGN ｡