Resequencing Delay for a Queueing System with Multiple Servers under a Threshold-Type Scheduling

Iwao SASASE  Shinsaku MORI  

IEICE TRANSACTIONS (1976-1990)   Vol.E73   No.6   pp.928-935
Publication Date: 1990/06/25
Online ISSN: 
Print ISSN: 0000-0000
Type of Manuscript: PAPER
Category: Engineering Science in General

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The resequencing delay for a queueing system with multiple servers under a threshold-type scheduling is analyzed. We first derive the general expressions for the average total delay which is the sum of resequencing delay and queueing delay. The expressions are also applicable to the conventional M/M/n queueing system as the special case of zero-threshold policy. Next, the numerical calculation is carried out for the queueing system with 3 servers under a threshold-type scheduling to consider the impact of the multiple thresholds on the average resequencing delay. It is found that the resequencing delay as well as the queueing delay for a queueing system with multiple servers of different service rates can be recuced under a threshold-type scheduling by selecting the threshold values appropriately. The threshold-type scheduling is more effective to reduce the resequencing delay compared to the queueing delay especially in the region of modest traffic intensity and as the difference of the service rates becomes larger.