Technical Discussion on three network modes of softswitch group Big Network

With the expansion of the application scale of NGN, the number of softswitch devices is gradually increasing. The problem of how to set up devices on the softswitch control layer must be solved. Softswitch devices have three network modes: mesh network, hierarchical Softswitch, and server locating network. These three methods have their own advantages and disadvantages and show different adaptability.

Background of the big network of the softswitch Group

At present, the domestic and foreign carriers of the NGN commercial and experimental scale are relatively small, and many manufacturers of softswitch have not yet achieved the interconnection of various services, but with the acceleration of the commercial deployment of NGN, it is expected that the next 2 ~ In three years, more Softswitch systems will be commercially deployed, and large-scale NGN networks will be formed. Prior to this, it was urgent to solve the problem of building a large-scale network by combining SoftSwitch. The control layer of softswitch equipment is a key issue.

Measure the test taker's knowledge about the large network of the softswitch control layer.

As the business volume and coverage increase, when the number of softswitch devices is large, you need to consider how to group large networks at the softswitch control layer. There are three methods for the softswitch group big network:

1. Softswitch Mesh Network　

This networking feature: the routing function is implemented by the softswitch device, and each Softswitch maintains the routing information of all users throughout the network; the static configuration of the softswitch routing information; changes in a management domain network, such as the addition or deletion of a Softswitch node, will lead to changes in the entire network data. The switches are in a logical mesh network structure, and the called Softswitch can be located through an address resolution; SIP/SIP-T or BICC can be used between Softswitch, from the current development point of view, SIP/SIP-T is the trend.

The advantage of this networking mode is that the network is simple and the requirements for Softswitch devices are not high. When the network size is small, it is a good choice. When the network size is large, this will bring about huge maintenance work.

2. Hierarchical networking structure of softswitch Devices　

The lower-level Softswitch is interconnected with the upper-layer Softswitch, and the routing information between the softswitch is static. The SIP/SIP-T or BICC can be used between the softswitch. The characteristics of this networking mode are as follows: the lower-level Softswitch is interconnected with the upper-layer Softswitch, the routing information static Configuration between Softswitch, And the SIP/SIP-T or BICC between Softswitch, but SIP/SIP-T is a trend.

The concept of hierarchical Softswitch is very similar to the existing hierarchical settings of the PSTN network. Basically, the concept of PSTN networking is moved to the NGN network, following the idea of the PSTN networking. The technology is mature, but the efficiency is low.

3. locating server networking through routing　

Introduce servers with routing functions), exchange routing information and provide routing services for SoftSwitch. This networking method is suitable for large-scale network networking of SoftSwitch. The characteristics of this networking mode are: locating the server and forming an IP Phone management domain ITAD with the softswitch of its service); inside the ITAD management domain; between the softswitch is static routing configuration, the protocol of SIP/SIP-T is adopted between SoftSwitch and the locating server, and the protocol of simplified TRIP or SIP can be used to exchange and parse routing information ); the Softswitch communicates with the locating server through the heartbeat signal. Two or more locating servers can be set for each management domain for redundant backup; route information is dynamically updated between ITAD management domains and locating servers through the TRIP protocol, and aggregated and exchanged between network elements.

4. The following table lists the advantages and disadvantages of the three Softswitch networks)

Figure 1

Suggestions on Softswitch networking

Considering the long-term O & M benefits of operators and the maturity of technologies, it is recommended that a small number of softswitch network routes be used in the initial network construction ), at the same time, the development and application of softswitch dynamic routing are promoted through the formulation of standards and laboratory tests. It is recommended that dynamic plane routing of locating servers be adopted for large-scale network construction.

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