Under NGN and Softswitch Technology

At present, the introduction of softswitch in mobile networks is also the first step of development:

--- Tandem Functions

In this case, it is basically the same as the softswitch and media gateway application modes of the fixed network, mainly to solve the IP communication between the mobile network and the fixed network. Softswitch has no mobility function and cannot support services in the mobile field.

--- Gmsc (Gateway MSC)

Softswitch is equivalent to Gateway MSC and has the concept of mobility. It uses the MAP/is41 interface to locate mobile users and support new mobile businesses.

--- Vmsc (visited or serving MSC)

The third step is to provide the softswitch function in the vmsc.

As a result, the maturity of softswitch in Mobile is the same as that in fixed networks. It is mainly used to replace the traditional network for providing IP phones.

2.3 protocol Maturity

2.3.1 Softswitch protocol system

The Softswitch Protocol requirements include:

--- The H.248 protocol with the relay gateway,

--- Sigtran protocol for intercommunication with No. 7

--- Protocol with IP terminal sip, H.248, MGCP

--- INAP, cap, and map protocols with existing intelligent networks

--- The existing h.323ip protocol for the telephone network.

--- SIP-T/BICC Protocol with other Softswitch

--- Various protocols with the Access Gateway

--- Open API Protocol

Standards and protocols related to Softswitch are the key to network convergence. Currently, the industry, including equipment manufacturers and service providers, is working hard to set up standards. We hope to introduce advanced services and voice applications to the data network and smoothly integrate with traditional networks. Now the standard work mainly involves: interoperability; media control protocol (such as MGCP, H.248), communication between soft switches (such as SIP-T, BICC), extended business platform protocol and API; complies with international telephone connection standards, security standards, and advanced services of softswitch transmission. Related Standards include H.323, MGCP, and sip. However, the relevant Softswitch standards need to be improved, unified, and widely accepted. The primary challenge facing Softswitch is the multi-protocol, which supports many protocols, and these Protocols come from different standardization organizations, this has brought many coordination difficulties for technical research, equipment production, communication and operation, and other aspects. At present, many work has been done in the standardization of domestic agreements. Some agreements should be standardized, and some are being formulated.

The following table lists the protocols that have been developed and are currently in progress in China:

2.4 maturity of softswitch networking

From the perspective of the network, there are still many problems to be studied in the networking of softswitch:

---- Collaborative work of multiple Softswitch

At present, the experiment of Softswitch is basically based on one Softswitch. Now some operators have started to test multiple SoftSwitch. From the perspective of the network, the single softswitch system solution is only suitable for small-sized operators and can be implemented quickly in small-sized networks. However, for large telecom operators, it is necessary to build nationwide Softswitch networks, no matter from scalability to interconnectivity and capabilities provided by the business, there are great restrictions. However, when more than two Softswitch networks are used, communication between the softswitch systems will be involved. The protocols in this field are not standardized, and the Protocols that each manufacturer can provide are also different, therefore, the cooperation and interworking of softswitch between different manufacturers are not mature enough.

---- Classification of Softswitch

If Softswitch can solve the collaborative work of multiple Softswitch, what network level should it adopt? Whether it is a level-1 or multi-level network. Some manufacturers also believe that if the level-1 system is adopted, even if multiple Softswitch schemes are adopted, this scheme is only suitable for medium-sized operators to implement in medium-sized networks. For large telecom operators, the scheme is a flat network, and its scalability is also difficult to meet the needs of telecom-level operators covering the whole country. As a result, some vendors even propose that Softswitch should also be divided into the terminal bureau level and the remittance level. If the local bureau services are provided through a unified business point across the network, the efficiency of service provision is very low due to complicated process interaction and media flow control, and may damage some business features, and reduced the flexibility of business improvement. In terms of networking, it is also proposed to set up a network system for multi-level location servers in a Softswitch Network. As a result, the problem of softswitch network organization is not very mature, and some problems need to be studied.

2.5 third parties provide business maturity

Since the standardization of open interfaces has not yet been completed, although some vendors can provide some third-party services, they are still limited to the devices of the same vendor. The cooperation between devices of different manufacturers and the provision of services are not very mature.

3. problems to be solved in the Development of softswitch in China

At present, various operators have begun to test and test the Softswitch technology. With the gradual improvement of the performance and implementation functions of the softswitch device, the following problems need to be solved to fully run on the entire Telecom Network:

3.1 address problems

As a node in the packet exchange network, a Softswitch device must have a unique network ID (IP address in the IP address network ). This ID number is generally limited and cannot be allocated randomly. As the size of the softswitch network expands and the number of user access increases, this problem will become increasingly prominent. A practical solution is to enable private ID numbers, but the ing between public and private ID numbers is followed. The device identification is the most basic problem in the construction of the softswitch network and is also the basis for the routing problem discussed below.