1. COT 5611 Operating Systems Design Principles Spring 2012
Dan C. Marinescu
Office: HEC 304
Office hours: M-Wd 5:00-6:00 PM

2. Lecture 11 - Wednesday February 15
Reading assignment: Chapter 7 from the on-line text
Last time:
Network architecture – the Internet
Layering
Link layer
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Lecture 11

3. Today Sharing a communication channel Multiple access protocols
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Lecture 11

4. How to share a multiple access channel
Scheduled access
TDMA
FDMA
Non-scheduled access
CSMA/CD  Ethernet
Random Multiple Access
Random multiple access
Channel model:
Slotted time
N transmitters/receivers
Only one transmitter can be successful.
If two transmitter use the same slot we have a collision
In a slot: S/C/I (S successful transmission, C collision; I idle slot)
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Lecture 11

5. First Come First Served (FCFS)
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Lecture 11

6. Splitting algorithms – the stack algorithm
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Lecture 11