Atm Network Research And Implementation Of Automatic Protection Switching Protocol

Due to the progresses of the computer technology and communication technology, and the subscribers'increasing demand for the data communication, communication network is developing towards the digital, broadband, integrated and intelligent way. This requires that various communication services should be unified on the same basic platform which guarantees the adequate broadband, adapts diverse services and provides different quality of service. So B-ISDN (Broad Integrated Service Digital Network) comes into being. ATM (Asynchronous Transfer Mode) which is the supporting technology of B-ISDN is confirmed by ITU in 1988. ATM is characterized by the high-usage, supporting high-speed switching and ensuring the quality of various services. It is a new multiplexing and switching system that can support voices, data, videos and multimedia. ATM is a good access to the integrated services and is suitable for constructing various services of information platforms. As the enterprises'information construction increasingly deepens, various high-speed data private wires are demanded more and more. The traditional DDN/ FR network fails to meet the fast increasing tendency of private wires services because of its limited coverage and high cost. The private wires services can bring generous profits to the operators. So how to provide the big customers with good QoS protection, secure and reliable high-speed private wires services by ATM/ IP/ SDH network becomes the operators'focus. In order to meet this demand, many companies have developed the Multi-Service Access Platform for the customers. Automatic Protection Switching (APS) protocol of ATM is a kind of protective mechanism guaranteeing that the customers' services can be transmitted reliably. It works at the ATM layer in the reference model. When the fiber of the ATM network connected with the user appears single point of failure, this kind of protocol can detect malfunction in time and restore the users' service transmission quickly. It can provide ATM network with stronger fault-tolerant ability and further guarantee to the reliability in the users' service transmission.