Systems Management Server 2003 bandwidth throttling does not completely use allocated bandwidth (830614)
The information in this article applies to:
- Microsoft Systems Management Server 2003
SYMPTOMSMicrosoft Systems Management Server (SMS) 2003 bandwidth throttling for both the Remote Access Server (RAS) Sender and the Standard Sender may not use all the allocated bandwidth.CAUSEThis problem occurs because the SMS 2003 RAS Sender and the SMS Standard Sender do not account for the time that it takes to transfer each data block (block transfer time). SMS bandwidth throttling is based on "sleep time". Sleep time forces a delay between each sent data block. For example, if the maximum available bandwidth is 40 Kbps and the Limit (% of connection bandwidth) setting for the RAS Sender or the Standard Sender is set to 75%, and the last sent block size was 120 KB, SMS uses the following formula to calculate the sleep time: block size (KB) x (1 / limit setting) x maximum available bandwidth (Kb/s) = sleep time (seconds)
Note 1 KB = 8Kb
120 KB x (1 / .75) / 40 Kb/s = 32 seconds This formula does not account for the block transfer time. You can use the following formula to calculate the block transfer time: block size / maximum available bandwidth = block transfer time
120 KB / 40 Kb/s = 24 seconds WORKAROUNDYou can use the formulas in the "Cause" section of this article to calculate the actual bandwidth for the SMS RAS Sender and the SMS Standard Sender. You must add the data block transfer time (24 seconds) and the sleep time (32 seconds) to calculate the overall time of 56 seconds and an actual bandwidth utilization factor of 43% and not 75% as specified in the Limit (% of connection bandwidth) setting of the SMS 2003 Sender properties. You can use the following formula to calculate the actual bandwidth utilization factor: block size (KB) / overall time (seconds) / maximum available bandwidth (Kb/s) = actual bandwidth utilization factor
120 KB/ 56s / 40 Kb/s =
42.8% For example, when you set the Limit (% of connection bandwidth) setting to 25%, the total time is: 24 seconds for the data block transfer time, 96 seconds for the sleep time (for an overall time of 120 seconds), and an overall bandwidth utilization of 20%. STATUSMicrosoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
| Modification Type: | Major | Last Reviewed: | 1/17/2006 |
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| Keywords: | kbnofix kbBug KB830614 kbAudITPRO |
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