SFM: Macintosh Computers Create a Lot of Network Traffic

• Microsoft Windows NT Advanced Server version 3.1
• Microsoft Windows NT Server versions 3.5 and 3.51
• Microsoft Windows NT Server version 4.0

SUMMARY

Macintosh clients' refresh rate may create a bottleneck in the Windows NT server. The Macintosh client issues a "GetVolParms," which is designed to refresh the directory of a mounted volume for file updates on any Macintosh running System 7.x or higher.

MORE INFORMATION

When a Macintosh client mounts a Windows NT Server Macintosh volume, the client will send a "GetVolParms" to the server every 10 seconds for the first 10 volumes mounted. When you have a large number of Macintosh clients connected to multiple Windows NT volumes, the Macintosh clients will create a bottleneck in the server's bandwidth for the network card resources.

Apple Computer has configured this refresh rate to adjust itself according to the number of volumes. If the number of volumes mounted is greater than 10, the "GetVolParms" adjusts itself so that the number of volumes equals the number of seconds for refresh rate. For example, if you have a Macintosh with 20 volumes connected, then the refresh rate will be 20 seconds for each of the volumes. If you have two hundred clients and each client has two volumes mounted, there will be four hundred (200x2) requests every ten seconds for a total of 2400 requests per minute.

The "GetVolParms" is a looping structure that will continue until the volume is disconnected. As soon as the "GetVolParms" is issued the internal counter will reset and wait ten seconds, depending on number of volumes mounted, and regardless of when the reply returns to the Macintosh client. If the "Current Queue Length" is busy and Windows NT Server takes five seconds to respond, the next request will occur in five seconds.

For individuals who wish to optimize their Macintosh Clients, third party products like Less Talk will allow the user or the administrator to configure and control the polling interval for each mounted volume.

Less Talk is manufactured by Information Presentation Technologies, Inc., a vendor independent of Microsoft; we make no warranty, implied or otherwise, regarding this product's performance or reliability.

Information Presentation Technologies, Inc. 555 Chorro St., Ste. A San Luis Obispo, CA 93405

805-541-3000 805-541-3037 (fax)

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