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Unformatted text preview: 1 Purdue University ECE ECE-547 547 Introduction to Computer Introduction to Computer Communication Networks Communication Networks Instructor: Instructor: Xiaojun Xiaojun Lin Lin Lecture Lecture 17 17 Purdue University Residual service time Residual service time ¾ From (6) we have: ( ) (1 ) ( ) Q E R E W ρ = − 2 ( ) ( ) 2 E E R λ τ = ¾ We can derive that 2 ( ) ( ) 2(1 ) Q E E W λ τ ρ = − ¾ Hence, 2 Purdue University Priority Priority Queueing Queueing ¾ Priority classes are used for a variety of reasons. ¾ Signaling information ¾ Fault notification ¾ Routing change update ¾ Congestion information ¾ Different grades of service (voice, video, etc.) Vital packets that could get delayed by being behind other packets if no priority is assigned. ¾ Two types of priority queueing systems ¾ Non-preemptive ¾ Preemptive Purdue University Non Non-preemptive priority queue preemptive priority queue r λ λ : : 1 r μ μ : : 1 ¾ r-classes of customers ¾ Arrival process of class k customer is Poisson with rate...
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This note was uploaded on 01/06/2010 for the course ECE 547 taught by Professor Xiaojunlin during the Spring '09 term at Purdue.
- Spring '09