EE 122 Discussion 91211 Transmission and Propagation Delay Propagation delay between Host 1 and Switch1 Transmission delay Host 1 Switch 1 Size of transfer Bandwidth of link Speed of light ID: 259397
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Slide1
Network Delays, Statistical Multiplexing
EE 122 Discussion
9/12/11Slide2
Transmission and Propagation Delay
Propagation
delay
between Host 1
and Switch1
Transmission delay
Host 1
Switch 1
Size of transfer
Bandwidth of link
Speed of light
Physical distanceSlide3
A
B
C
Transmission delay
doubles
Brown
packet waits for half
the trans.
delay of blue packetQueuing Delay (Problem #3)Slide4
Statistical Multiplexing
Over-subscribe “peak” requirements of flows and
hope
that “average” requirements are under capacity“Hope is a good thing, maybe the best of things…” Slide5
Data Rate 1
Data Rate 2
Data Rate 3
Animation from class
TimeTimeTime
CapacitySlide6
Data Rate 1
Data Rate 2
Data Rate 3
Animation from class
Time
TimeTime
Capacity / 3Capacity / 3Capacity / 3Slide7
Animation from class
Time
Time
Time
Below capacity of link all the time!Slide8
Why and when will this work?
Zone #2
Time
Time
TimeZone #1Zone #3
Probability of a flow transmitting in each time zone is 1/3What is the expected value of the overall flow?