MTP 3 User Adaptation (M3UA) - SIGTRAN Stack

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M3UA is a protocol for supporting the transport of any SS7 MTP3-User signaling (e.g., ISUP and SCCP messages) over IP using the services of the Stream Control Transmission Protocol (SCTP). In addition, provision is made for protocol elements that enable a seamless operation of the MTP3-User peers in the SS7 and IP domains. This protocol would be used between a Signaling Gateway (SG) and a Media Gateway Controller (MGC) or IP-resident Database.

SG: SG is a Signaling Agent, which interface between the SS7 and IP network. It appears the SS7 SP to the SS7 .  SG is logical entity with contains the one of more SGP.

SGP: SGP is logical instance of SG. SGP is a physical entity, which has the association between to ASP. All SGP within the SG have the view towards the SS7 Network.

AS: AS is a logical entity, which serves as a specific Routing key. It is present in IP domain. An AS contains set of one or more ASP. There is 1:1 mapping of AS to routing key i.e. there is one routing per AS.

ASP: ASP is process instance AS. it is physical entity which have association with the SGP. Unlike SGP, An ASP can be part of one or more AS.

IPSP: IPSP is a process instance of IP-based application. it is same as ASP but not connected to SS7 network via SGP.  When two users are present in IP domain we only need IPSP.

Routing Key: Routing key is set of SS7 parameters and parameter values that uniquely define the signaling traffic to be handled by particular AS.

Routing Context: RC is a unique identifier of a Routing key.  RC can user configurable. The scope of RC is global on SGP side.                                    

                                         ASP/IPSP                                           SGP/IPSP
                                         ===================================
                                                     ——————- ASP UP————–>
              INACTIVE State      <—————–ASP UP ACK———
                                                     ——————-ASP ACTIVE——–>
                   ACTIVE state      <————ASP ACTIVE ACK——-
                                                     ——————BEAT——————->
                                                     <—————-BEAT ACK————-

To make down the M3UA association:

                                      ASP/IPSP                                                   SGP/IPSP
                                      =======================================
                                                      ——————-ASP DOWN————–>
                                                      <——————ASP DOWN ACK——-
                                                      ——————-ASP INACTIVE———->
                                                      <—————–ASP INACTIVE ACK—–

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