Streaming Variable Bit-Rate Media Streams - Scalable Continuous Media Streaming Systems - page 135

60

55

50

45

Optimal Smoothing

AMDR scheduler

40

35

MDR scheduler

30

0 50 100 150 200 250

Client Buffer Size (MBs)

Figure 7.7a Mean client waiting time versus client buffer size
Note : The MDR scheduler does not have a buffer constraint.

3000

2800

2600

optimal smoothing

2400

AMDR scheduler

2200

2000

MDR scheduler

1800

0 50 100 150 200 250

buffer (Mbytes)

Figure 7.7b Worst-case client waiting time versus client buffer size
Note : The MDR scheduler does not have a buffer constraint.

the simulations for a range of system capacity from 100 Mbps to 1 Gbps and plot the mean
and worst-case waiting times in Figure 7.8. Comparing different schedulers, we observe that
AMDR and Optimal Smoothing have nearly identical performance while the MDR scheduler
consistently achieves lower waiting time. This is expected, as the MDR scheduler is not subject
to buffer size constraint, which in this case equals to 32 MB. Comparing the waiting time
against the system bandwidth, we can see that the waiting time increases significantly at lower
system bandwidth settings. Nevertheless, the differences between the AMDR scheduler and