This paper deals with network performance of 64kbit/s-based services supported in an ATM network and an ATM interworking network with 64kbit/s-based networks. It first clarifies network performance issues giving a model and objectives of study and experiment. A result of computational analysis is then presented, where a cell loss ratio of an order of 10-4 or 10-5 is obtained to give a performance equivalent to that currently used as objective values in existing networks for a 64kbit/s digital level. In order to capture the impact of cell loss and associated performance for application levels, an experimental test has been carried out using typical applications. Test results show that the cell loss ratio needs to be approximately ten times better than the bit error ratio for comparable performance for application levels. A cell loss ratio of better than 10-5, or an order of 10-6 considering an interworking situation, seems to be necessary according to the test results. It is further clarified by the test that a single cell is more valuable than a multiplexed cell for providing better cell loss resilience characteristics. Although not all applications of 64kbit/s networks have been tested, it is expected that the test results can be used as guidance for considering the support of 64 kbit/s services in an ATM and interworking networks.

Corporate information communication systems are recently orienting the integration of various kinds of communication services. A PBX and a LAN have been indispensable in the realization of these systems. Some PBXs are orienting towards distributed switching architecture, and LAN systems are increasing their scale. Both requirements can be realized by means of a high speed loop optical fiber network. An integrated LAN should satisfy the required performance as a multimedia LAN and should be provided self-healing functions which heal failures automatically, to enable continuous operation of the entire system. This paper introduces a multimedia LAN, which attaches importance to the self-healing functions, called SHM-LAN. Its system architecture and its characteristics, such as efficient channel allocation are presented. This paper also deals with the self-healing functions and some applications.