Systems Management Server Sender Packet Size Computation

• Microsoft Systems Management Server versions 1.0 and 1.1

SYMPTOMS

The Sender is designed to dynamically compute a packet size based on link speed when sending packages. It begins with a 1024 byte packet and records the time to transmit. Based on this time, the sender increases or decreases the packet size as necessary within the range of 1024 to 262144 bytes.

However, there is a range of speeds where the Sender does not adjust packet size correctly, forcing the maximum packet size on a link that is too slow.

CAUSE

The Sender incorrectly computes the packet size.

NOTE: In many WAN environments 56k bit to 256k bit links are common. Some WANs have links below 38k bits per second, such as when using modems for a RAS Sender address.

The following table lists link speed and the corresponding packet size:

   Link Speed   Byte Buffer
   (bits/sec)   Packet Size
   ----------   -----------
   262144       262144
   6552         245700
   6112         229200
   5672         212700
   5232         196200
   4792         179700
   4352         163200
   3912         146700
   3472         130200
   3032         113700
   2592         97200
   2152         80700
   1712         64200
   1272         47700
   832          31200
   424          15900
   216          8100
   104          3900
   48           1800

STATUS

Microsoft has confirmed this to be a problem in Systems Management Server versions 1.0 and 1.1. This problem has been corrected in Systems Management Server version 1.2.