ATM protocol adaptation for EMI/EMC environment

摘要

Traditionally telecommunication networks are primarily circuit switching based with variety of protocols developed specifically to have call control while computer networks are packet switching based with specific protocols for having traffic control and packet routing. However, in the context of evolving high performance network as objective the assessment of the suitability of conventionally evolved protocol needs to be done. As user applications also will use this type of network infrastructure hence suitably adapted form of existing protocols are to be used by them. This will ensure compatibility with existing protocols at the same time will provide immunity against electromagnetic interference by interconnecting heterogeneous media. The communication system at each end can be branched into classical 7 layers OSI model with transactions being done between peer entities. The electromagnetic interference in the interconnecting media directly affects the physical layer but indirectly all upper layers also. It causes different types of error patterns to be introduced in the physical layer bit streams. These error patterns are to be analyzed to quantify their effect on the communication system. Various classical channel models viz., Poisson, Neymann Pearson, Pareto, Markov etc. can emulate various segments of the interconnecting media thereby giving fairly good Idea of error pattern behavior at physical layer. This information is useful in selecting suitable FEC with interleaver so as to have very less residual error out of physical layer at other end. Still upper layers are affected because of this residual error. The paper focuses on the various issues concerning adaptation of ATM layers so that overall electromagnetic compatibility of the system can be achieved.