Large Deviation Techniques for Traffic Engineering

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1. Units of the s, t parameters
2. Units (not again!) of the buffer
3. The trace file with .tr extension
4. Using the two or three dataset option

1: Units of the s, t parameters
The option -eb of the msa program accepts the value of s in kb^-1 and the value of t in epochs of the trace file. The latter MUST be an integer.
For example, to compute the effective bandwidth of the star2.tr trace, which has an epoch of 40 msec, for s=.01135 kb^-1 and t=0.16 msec then you use the following command line

msa star2 -eb .01135 4

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2: Units (not again!) of the buffer
The units of the buffer B are determined by the trace file. For example, the second line of the star2.tr file contains:

# bits_per_info_unit = 424

which says that that 1 unit is 424 bits (i.e., one cell). If such a line does not exist, then the default value is one cell. Hence, the following command:

msa star2 -load 1405 149 7

indicates that the buffer is 1405 cells.

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3: The trace file with .tr extension
The .tr extension indicates that the trace file is in the following format

# epoch_in_msecs = 40.000000
65
4
5
8
6
6
10
...

The older .trace extension, which you should avoid, indicates that the trace file is in the following format

# epoch_in_msecs = 40.000000
1 65
2 4
3 5
4 8
5 6
6 6
7 10
...

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4. Using the two or three dataset option
When using the two or three dataset option, be sure that all files are of the same type (.tr or .trace) have the same epoch_in_msecs, and the same BITS_PER_INFO_UNIT. Also note that the number of epochs will be the smallest number of epochs.

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