With the gradual maturity of Softswitch technology, the demand for building a value-added business platform in the softswitch system has gradually emerged. The existing value-added business platform of telecom networks already has a mature intelligent network platform, how can we use existing intelligent network resources and introduce Parlay Application servers and SIP application servers in the softswitch system into the softswitch service platform to provide users with richer services, is the focus of this study.
I. Composition of the softswitch business platform
One of the main ideas in Softswitch networks is the separation of business and control, as shown in 1, the service platform of Softswitch is mainly composed of Intelligent Network, application server, policy server, Media Server, location server, AAA server, network management system and Billing Account System.
The Application Server provides a business execution environment to provide value-added smart services and various personalized services for users connected to the softswitch network, application servers in the broad sense should include traditional Intelligent Network SCP, SIP application servers, and third-party application servers connected Through Parlay gateway.
A Media Server is an independent device that provides special media resources in the softswitch network. It provides media resources required by various services under the control of the softswitch or application server, various resource functions including DTMF signal collection and decoding, generation and sending of signal sound, sending of recording notification, meeting, conversion between different codec algorithms, and communication and management and maintenance functions.
The network management system provides network management functions for all devices under the softswitch framework system.
The billing cAMP system provides all end users under the softswitch framework to open accounts, handle service billing, generate bills, and interact with users.
The policy server implements communication policy management with each component of the softswitch system through the COPS protocol. tags are assigned based on business needs and features, and control and accept are enabled to ensure QoS for different business flows, meet the user's increasingly personalized business needs.
The location server records the user information of all users in the softswitch network, including the user location and attributes, for other devices in the softswitch network, such as the softswitch and application server, to query user information.
The AAA Server performs user authentication, authentication, billing, and other functions through interaction with Softswitch.
Figure 1 Softswitch Network
Ii. Construction of softswitch business platform
1. Protocol Analysis Between Softswitch networks and business platforms
Softswitch works with the existing intelligent network to provide services. Softswitch acts as the SSP function and directly provides services through the intelligent network SCP. Softswitch uses the INAP/CAP/WINMAP protocol to access the intelligent network SCP through the signaling gateway. The protocol between the softswitch and the AAA Server currently has the Radius and Diameter protocols; the protocol between the softswitch and the network management system is SNMP, and the policy server interacts with the softswitch through the COPS protocol; the interfaces between the softswitch and the location server can be the LADP protocol and the TRIP Protocol (the routing protocol for the transferred telephone over the IP network). interfaces between the softswitch and the Media Server (MediaServer) are the MGCP or H.248 protocol; interfaces between SoftSwitch and Application Server (AppServer) are INAP, SIP or ParlayAPI interfaces, and interfaces between SoftSwitch and Billing accounting system Billing are XML interfaces.
2. steps for building the softswitch business platform
At present, Softswitch is introduced, and the main fields involved in the softswitch equipment are the replacement of the original switch equipment. Therefore, the services provided by Softswitch are mainly the basic and supplementary services of speech.
With the gradual construction of softswitch, the softswitch will gradually integrate the fixed network, mobile network and wireless network, and the softswitch will communicate with the existing SCP through the SG signaling gateway, act as a virtual SSP service exchange point), so as to realize the existing smart services of the traditional fixed intelligent network, Mobile Intelligent Network, and wireless intelligent network, make full use of the original intelligent network resources.
To meet the more open business needs of users, add application servers on the Internet to implement existing value-added services, smart services, and future services, add the WebServer in the network as the service registration and selection platform for IP users, as the service user window. The Application Server can be implemented in two ways: Parlay Application Server and SIP application server. The Parlay Application Server can provide different abstract levels of business development interfaces, so that different capabilities and types of business developers can develop a wide range of businesses. For example, you can provide ParlayAPI Interfaces Based on CORBA, Java API Interfaces Based on JAINSPA standard, Java API Based on ans, AND Interfaces Based on XML, CPL, and VoiceXML. The abstract layers of these interfaces gradually increase, but the interface capabilities are also gradually reduced. business developers can select the appropriate development interfaces based on their business needs and capabilities. IETF provides two types of service development technologies for SIP application developers: one is for sip cgi and SIP Servlets with high credibility, and the sip cgi and SIP Servlet API specifications are developed. These two technologies have strong functions, but improper use may cause insecure application servers. The other Language is CPLCall Processing Language (CPLCall Processing Language), which is a scripting Language based on XMLExtensible Markup Language developed by IPTEL Working Group of IETF, it is mainly used to describe and control Personalized Internet telephone services, including call Policy Routing, call screening, call logs, and other services, with weak processing capabilities, this ensures that the CPL business logic compiled by common users will not cause damage to the application server.
Finally, the Standard Service API interfaces of the Application Server are provided to third-party developers who are constantly developing various new services for users.
Introduction steps of NMS system, AAA Server, Media Server, location server, and Policy Server: as a necessary element of network management, the NMS system will be introduced at the initial stage of business platform construction; AAA servers, Media Servers, location servers, and Policy servers are gradually introduced along with the diversity of application servers and user value-added services.
Iii. Services on the softswitch business platform
1. Basic voice services and supplementary services: provides basic calls and supplementary services in the original network, such as pre-call forwarding and non-disturbing services;
2. Intelligent Service: provides services in the original intelligent network, such as pre-payment and VPN services;
3. special Business: This type of business mainly refers to the special business that combines voice, data and multimedia. Typical applications include unified messaging business, instant messaging, multimedia conference telephone business, And VOD), whiteboard, online games, voice portals, General numbers, click-and-dial services, click-and-fax services, Web800 services, visual phones, Internet call waits, and many other services.
Iv. Conclusion
As the Softswitch technology continues to mature, the Service Platform of softswitch will gradually improve, and users will enjoy more diverse services brought by SoftSwitch.
