Architecture and performance of MLAN: A multimedia local ATM network

In this paper we present a Multimedia Local ATM Network (MLAN) protocol suitable for campus environment which (i) operates in the native ATM mode, (ii) does dynamic and fair bandwidth allocation as per desired criteria, (iii) guarantees continuous access to real time and high priority data traffic, and (iv) offers connectionless as well as connection-oriented service for MLAN-ATM network communication. The protocol has been designed for a bidirectional broadcast bus system topology. A new `polling inactive customers only (PICO)' reservation technique exploits the characteristics of the multimedia traffic which enabled us to reduce the average overhead due to bus propagation delay. Also, new concepts of secondary polling and transmissions have been introduced to improve LAN throughput under low traffic conditions. The protocol performance has been determined analytically as well as by computer simulation using a multimedia traffic model developed in the paper. Results show that the protocol performance remains the same at all traffic compositions if the offered load does not change and is independent of the bit rate (R) when R≥50 Mbps. Based on the results, the proposed broadcast bus system MLAN architecture is well suited for designing high speed multimedia ATM LANs with a modest number of terminals over a 1 to 3 km bus.