{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Lecture24_2up

# Lecture24_2up - ECE-547 Introduction to Computer...

This preview shows pages 1–5. Sign up to view the full content.

1 Purdue University ECE ECE- 547 547 Introduction to Computer Introduction to Computer Communication Networks Communication Networks Instructor: Instructor: Xiaojun Xiaojun Lin Lin Lecture 24 Lecture 24 Purdue University Model for Flow Control Model for Flow Control ¾ Assumptions: ¾ Infinite buffers ¾ Zero propagation delay ¾ Zero acknowledgement delay ¾ Poisson arrivals and exponential service times ¾ Operations: ¾ Packets that arrive into the network & find N packets in the V.C. are dropped.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
2 Purdue University Closed Closed Queueing Queueing Model Model ¾ V.C. with Poisson arrivals ( λ ). ¾ Service time at each queue i is exponentially distributed i ). ¾ No ack. delay or propagation delay. 1 2 3 M μ 1 μ 2 μ 3 μ M N λ Purdue University Closed Closed Queueing Queueing Model Model ¾ Question we would like to answer: ¾ Time Delay ¾ Throughput in the V.C. using a sliding window flow control mechanism ¾ Qualitative feel: ¾ No Control: λ Delay Throughput ¾ Control: • (1) λ Delay Throughput (bounded by N) • (2) N Delay Throughput
3 Purdue University Sliding Window Flow Control Sliding Window Flow Control ¾ Best Control Scheme: ¾ Shortest delay for a given throughput, or vice- versa. ¾ No propagation delay: ¾ Optimum N M Purdue University Quantitative Analysis Quantitative Analysis ¾ Fact: ¾ For product-form queueing networks, any subnetwork can be replaced by one or more “composite queues” with a state dependent service rate ¾ Remaining network retains exactly the same statistical behavior.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 13

Lecture24_2up - ECE-547 Introduction to Computer...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online