Method and system for implementing messaging services and a message application server

A method for implementing IP Multimedia Subsystem (IMS) messaging services, comprising:

• receiving, by an originating Call Session Control Function (CSCF1), a session connection creation request sent by a calling user;
• forwarding, by the originating CSCF (CSCF1), the session connection creation request to an originating Message Application Server (MAS1) in order to create a connection between the calling user and the original MAS (MAS1);
• determining, by the original MAS (MAS1), whether the calling user and a called user belong to a same IMS domain according to user registration information, wherein the calling user is a registered user of an IMS domain and the called user is a registered user of an IMS domain;
• forwarding, by the original MAS (MAS1), the session connection creation request to the called user through the original CSCF (CSCF1) and bypassing a terminating MAS and a terminating CSCF, in order to create a connection between the called user and the original MAS (MAS1), if the calling user and the called user are in the same IMS domain;
• and
• receiving a message body sent by the calling user through the connection between the calling user and the original MAS (MAS1), and forwarding the message body to the called user through the connection between the called user and the original MAS (MAS1).

A Message Application Server (MAS), comprising:

• a user registration information storing unit, adapted to store user registration information;
• a receiving unit, adapted to receive a message body sent by a calling user;
• a first determining unit, adapted to determine whether the calling user and a called user are in a same IP Multimedia Subsystem (IMS) domain according to the user registration information stored in the user registration information storing unit, wherein the calling user is a registered user of an IMS domain and the called user is a registered user of an IMS domain;
• and
• a first sending unit, adapted to send the message body received by the receiving unit from the calling user to the called user bypassing a terminating MAS and a terminating Call Session Control Function (CSCF) when the first determining unit determines that the calling user and the called user are in the same IMS domain.

A Message Application Server (MAS), comprising:

• a user registration information storing unit, adapted to store user registration information;
• a first receiving unit, adapted to receive a session connection creation request sent by a calling user in order to create a connection between the calling user and the MAS (MAS1);
• a second receiving unit, adapted to receive a message body sent by the calling user through the connection between the calling user and the MAS (MAS1);
• a determining unit, adapted to determine whether the calling user and a called user are in the same IMS domain according to the user registration information stored in the user registration information storing unit when the first receiving unit receives the session connection creation request from the calling user, wherein the calling user is a registered user of an IMS domain and the called user is a registered user of an IMS domain;
• and
• a sending unit, adapted to forward the session connection creation request to the called user bypassing a terminating MAS and a terminating Call Session Control Function (CSCF), in order to create a connection between the called user and the MAS (MAS1), when the determining unit determines that the calling user and the called user are in the same IMS domain, and forward the message body to the called user through the connection between the called user and the MAS (MAS1).