Intelligent evolution of fixed network based on softswitch

1. Problems currently faced by the fixed network

1. Difficult to quickly deploy new services across the entire network

At present, there are many types of switches in the fixed telephone network, with uneven functions, and the end office does not have the ability to trigger SSP services. The development of each new service requires the upgrade of the entire network end office switch, and the maintenance cost continues to increase. Due to the age of some standard switches, it has been unable to support new functions. In addition, each business needs to build a new intelligent network system. The overlapping of business networks leads to serious routing problems. For example, the fixed-line color ring back tone service requires the called end office to trigger service, which also causes waste of circuit resources and an increase in service failure points.

2. Unable to achieve centralized management of user data

The user data of the existing fixed network is all scattered and stored in each end office, which makes it very difficult for operators to count and manage user data. Since service triggering is all performed at the end office, the nesting capability of the service is greatly limited. The solidification of user data also led to the inability to carry out mixed number allocation and number portability services.

Second, the use of soft switching technology to achieve intelligent fixed network

Soft switching equipment is used to replace the traditional tandem office, the relay gateway and signaling gateway are connected to the end office, and new SDC equipment is built in the entire network to realize the centralized management of user data. Through the introduction of soft-switching technology, the network intelligent transformation is well achieved. The use of softswitch technology to achieve network intelligence solutions has the following advantages.

1. Reduce network construction and maintenance costs

Softswitch systems use packet switching technology, which increases bandwidth utilization and saves investment in trunk lines. The packet-switched networking mode is more flexible, and the bearer network generally adopts a method of building a new IP private network or adding MPLS VPN in the local metropolitan area network. Compared with traditional switchboards, softswitches have large system capacity, small overall size, and centralized operation and maintenance. Therefore, the use of softswitches can also save investment in surrounding supporting construction. Taken together, the cost of next-generation networks based on packet switching technology will be lower than existing PSTN networks.

2. Strengthen the ability to provide services

The use of softswitch as the tandem layer device can solve the above-mentioned inconsistency of the functions of the various standard switches, service triggering is performed at the end office, and it is easy to produce problems such as detours, improve the network's ability to support new services, and achieve intelligent service nesting . After the introduction of softswitch, users can also directly provide broadband NGN services, such as video telephony and video conference, through softswitch. Softswitch provides open service interfaces, enabling third-party manufacturers to develop new services that meet user needs through common interface protocols such as PARLAY.

3. An important step in the evolution of PSTN networks to NGN

The evolution from fixed network to IMS has become an inevitable trend, but there is no clear implementation plan for the specific evolution. In order to reduce investment risks and make full use of existing PSTN network resources, it is not appropriate at this stage to deploy softswitch equipment on a large scale across the entire network. Network intelligence first solves the replacement of the tandem level, moves the service trigger point up to the tandem office, weakens the functional requirements of the PSTN end office, and can be regarded as the first step in the evolution of NGN. The evolution of the IMS architecture provides the foundation.

Third, the intelligent network transformation plan using softswitch

In a network intelligent solution that uses softswitch to replace the original tandem bureau, an independent user data center equipment (SDC) needs to be built to centrally manage user data.

1. Network structure

The new independent user data center equipment (SDC) networking structure is shown in Figure 1.

Independent SDC network structure diagram