DOCUMENT:Q174033  16-DEC-1999  [exchange]
TITLE   :XFOR: Performance Tuning a 16Mbps Token Ring Network for PROFS
PRODUCT :Microsoft Exchange
PROD/VER:winnt:5.5
OPER/SYS:
KEYWORDS:kbinterop

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft Exchange Server, version 5.5 
-------------------------------------------------------------------------------

SUMMARY
=======

It is possible for Microsoft Exchange Administrators to improve performance of
the Microsoft Exchange PROFS connector over the Microsoft SNA Server connection.
The following information may be helpful in reaching that goal.

MORE INFORMATION
================

The following actions improve the performance of the PROFS connector over SNA:

1. Maximizing the SNA Basic Transmission Unit (BTU) size.

   On a 16Mbps SNA Token-Ring network, the maximum SNA BTU size is 16393. To
   support this configuration the Token Ring Driver must be able to handle this
   packet size. In the Control Panel, click the Network icon, click the Adapters
   tab, and configure the Token Ring driver. If the maximum size is not
   configurable, consult your card vendor for the maximum packet size permitted.
   For maximum performance, select a reasonable packet size above 1K byte on a
   token ring network.

2. Update BTU in the 802.2 setup profile.

   In the SNA, select a BTU size that is smaller than the packet size. A
   reasonable BTU size ranges between 1929 and 16393 bytes (16K+9). This
   parameter must be less than or equal to the VTAM MAXDATA size. The RSCS PARM
   Buffer Size can be configured to control the RU size of the mail session.
   Configure the RSCS PARM B parameter to support RU size larger than 3K. This
   can be accomplished using an updated version of WINRUI32.DLL supplied by
   Microsoft or in the latest Microsoft SNA Server Service Pack.

3. Configuring the Host side:

   The VTAM MAXDATA parameter should be configured to take advantage of the
   token-ring high bandwidth. It must match the BTU size specified in the SNA
   Server mentioned above.

4. For information about Maximizing the IND$FILE 3270 Host file Transfer
   Throughput, please see the following article in the Microsoft Knowledge
   Base:

   Q125881 Maximizing IND$FILE 3270 Host File Transfer Throughput

Additional query words: linakge sna profs 802.5

======================================================================
Keywords          : kbinterop 
Technology        : kbExchangeSearch kbExchange550 kbZNotKeyword2
Version           : winnt:5.5
Issue type        : kbhowto

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 1999.