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# Slow Performance over IBM Software Source Routing Bridge

Article ID: 117715

Article Last Modified on 8/9/2004

APPLIES TO

- Microsoft Windows for Workgroups 3.11

This article was previously published under Q117715
3.11
WINDOWS
kbnetwork kbprb kbfile

## SYMPTOMS

Data transfers across a source routing bridge are very slow or appear to hang.

## CAUSE

Windows for Workgroups (NetBEUI protocol) over a Token Ring Source Routing Bridge advertises a Largest Frame (LF) size of 8130 bytes. However, the Maxframe size is negotiated at 156 bytes. This causes very slow data transfer.
A network trace illustrates the problem:

       Destination   Source        Summary
       Server      WFWClient<00>   NETB D=2B S=16 Session initialize

       NETB: ----- NETBIOS Session Initialize -----
       NETB:
       NETB: Header length = 14, Data length = 0
       NETB: Delimiter = EFFF (NETBIOS)
       NETB: Command = 19
       NETB: Flags = 89
       NETB: 1... .... = NO.ACK ability

       NETB: .... 100. = Largest frame value = 4 <<<8130 bytes -IBM Spec

       NETB: .... ...1 = Version 2.0 or higher

       NETB: Max data receive size = 156     <<< Small Frame size negotiated.

       NETB: Transmit correlator = 0000
       NETB: Response correlator = 0016
       NETB: Remote session number = 43
       NETB: Local session number = 22

If the bridge advertises a size OTHER THAN 8130 bytes, this problem does not occur.

## WORKAROUND

An updated NETBEUI.386 file is available to correct this problem. Replace your existing NETBEUI.386 file with the updated version. For information about how to obtain the updated driver, refer to the More Information section below.
The following options allow you to work around this problem:

- Use the real-mode NetBEUI protocol.
  -or-
- Execute "Net start Full" at the command prompt before running Windows for Workgroups.
  -or-
- Configure the bridge by changing a Largest Frame size (smaller or larger).
  In a case where an IBM software bridge is used to connect two 16 MB rings, it is not possible to change the LF size on the bridge software. In this case, you can bring down the network ring to 4 MB, or install a hardware bridge.

NOTE: This problem does not occur on LAN Manager/Windows workstations.

## MORE INFORMATION

The following file is available for download from the Microsoft Download Center:

Download Netbeui.exe now

For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 How to Obtain Microsoft Support Files from Online Services

Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file.

## STATUS

Some of the products discussed here are manufactured by vendors independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability.

Additional query words: 3.11 TR bridging client hangs freezes locks

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