Technical data

Proceed as follows to calculate the required target rotation time:
➣ Work out the maximum possible number of frames from all stations that
can occur in one token rotation distinguishing between the different
types of frame (e.g. SDN, SDA frames). Frames on predeifined S5-S5
links count as SDA frames.
➣ Calculate the "worst case" target rotation time using Table 17.13. You
must then add 11 bit time units for every data byte to the basic
overhead from the table (BTU).
➣ Then multiply the "worst case" target rotation time by the correction
factor 0.6.
Type of
frame
9.6 19.2 93.75
187.5 500 1500
Token (LAS<3)
88
88
165
195
97
97
195
160
195
195
410
270
320
320
690
450
750
215
1650
850
2700
450
4950
1950
Token (LAS>3)
GAP
SDN
SDA
SRD
215
345
225
295
295
430
465
610
1100
1300
3150
3150
Data rate in Kbps
Table 17.14 Basic Overheads of the Frames Relative to the Data Rate (in BTU)
B8976060/02 Appendix
17 - 27 Volume 1