| Popis: |
In this paper, the analysis of theproperties of modified Network double Ring(NdR) topologies has been presented. Thespecial type of these structures, namely opti-mal and ideal graph, has been defined. Thebasic parameters (diameter and average pathlength) were calculated and described by for-mulas which make possible evaluate these pa-rameters for any NdR graph without experi-ments, next the comparison of the analyzingstructures has been carry out. 1 Introduction The choosing of the interconnection network topology hasthe biggest impact on efficiency, speed, reliability andcost of the telecommunications or computer systems [1].These networks can be modeled by symmetric digraphs,i.e., a directed graph G with vertex set V(G) and edgeset E(G), such that, if [v i ;v j ] is in E(G), then [v j ;v i ] isalso in E(G). So any edge of digraph connecting ver-tices v i and v j can be replaced by two directed edges[v i ;v j ] and [v j ;v i ] [2]. It is obvious that the best ser-vice and reliability parameters one can obtain by formingcomplete networks (described by a complete graph), butonly small networks can be built in this way. In [3], a sur-vey of known topologies has been presented. Among theanalyzed topologies that would be used in designing thedistributed structures, the authors of this paper have cho-sen rings as they are very simple and extensible. They arenot expensive (number of edges is equal to the number ofnodes), are regular and symmetric, but possess poor trans-mission parameters. A modification of this type graphsare chordal ring structure [4, 5]. The chordal ring is a ringwith additional chords. It is defined by pair (p;Q), wherep is the number of nodes of the ring and Q is the set ofchords. Each chord connects every pair of nodes of thering that are at distance q |
