Research And Implement On DDN Service Portability

With the technological update and similar business replacement in recent years, DDN (Digital Data Network) is facing tough problems like inability to respond to the prompt needs of the data business, low speed (64N bits), high cost in network construction and maintenance, and failing to fulfill the multiple business needs of customers, which has caused the DDN business to decrease quickly and go into decay period. Currently, DDN in Telecom has the problems of old equipments, lack of spare parts, problematic network management, many weaknesses in network, high turnover rate of maintenance personnel, low usage rate of resources. All these make it difficult to ensure high quality telecommunication service. Besides, in recent years, China Telecom spares no pains promoting the replacement of copper with fiber in network supporting. As current electronic cables are mainly made of copper, they are phasing out and replaced by fiber cables. It greatly influences the business where around 90% DDN users are accessing network totally via electronic cable.Based on current situation, to ensure the effective use of current network resources, cost-effective transfer of DDN service via the methods of transferring network and increasing network speed, this article is studying DDN service network transfer solution in the following four areas:current status of DDN operation, feasibility study of the service transfer solutions, analysis of different solutions, implementation of DDN service transfer solutions and performance evaluation. After on-site investigation on provincial DDN points and thorough analysis of current network structure, maintenance status, operational income and future development trend, two solutions are defined. One is to combine ATM network with DDN, the other is to combine transfer network with DDN. After further analysis and comparison, the final solution is to combine MSTP (Multiple service transfer platform) with DDN. It ensures that DDN could be smoothly transferred into or be merged to other network, and, step by step, realizing the shrinkage of DDN service & network and phase-out of idle equipments.So far, this DDN transfer solution has been implemented in six branch companies of China Telecom. Electric transfer needs of below 2Mbit/s are now supported by MSTP equipments with 64k cross transfer capability. It paves the way for future on-line upgrade for users who are currently using low speed network.