A Connection-Level Design of Multistage Nonblocking ATM Switches

Supot TIARAWUT  Tadao SAITO  Hitoshi AIDA  

IEICE TRANSACTIONS on Communications   Vol.E77-B   No.10   pp.1203-1208
Publication Date: 1994/10/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Switching and Communication Processing
nonblocking,  ATM switch,  multistage switching network,  connection admission control,  

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It is desirable to design an ATM switch that is nonblocking at the connection level by using simple connection admission control (CAC) schemes. To accomplish this goal, it is necessary to consider the relationships between CAC, cell-level quality-of-services (QOS), and the structure of multistage switches as well as switch modules. In this paper, we formulate a framework to design a multistage nonblocking ATM switch. We show that if a switch has the property of the Sufficiency of Knowledge of External Loads (SKEL), i.e., the property that its cell-level performance is robust to the distribution of incoming traffic among all inputs, then the switch is also nonblocking at the connection-level by using a simplified CAC that guarantees QOS of a connection by controlling the aggregate loads on outputs. Furthermore, we show that a Clos three-stage network using SKEL switch modules and Multipath Self-Routing (MPSR) also has the SKEL property and is a nonblocking switching network that needs CAC only at its outputs. We also demonstrate a design of multistage nonblocking ATM switches with Knockout switch modules.