Maximum BTU limit for Dumb SDLC interface (236105)


The information in this article applies to:

  • Microsoft SNA Server 3.0
  • Microsoft SNA Server 3.0 SP1
  • Microsoft SNA Server 3.0 SP2
  • Microsoft SNA Server 3.0 SP3
  • Microsoft SNA Server 3.0 SP4
  • Microsoft SNA Server 4.0
  • Microsoft SNA Server 4.0 SP1
  • Microsoft SNA Server 4.0 SP2
  • Microsoft SNA Server 4.0 SP3
  • Microsoft Host Integration Server 2000
  • Microsoft Host Integration Server 2004
This article was previously published under Q236105

SUMMARY

When you use the IBM SDLC Dumb interface, the maximum BTU (Basic Transmission Unit) is 521 bytes. The IBM SDLC interface is provided by the Ibmsdlc.dll file. This dynamic link library is provided by Microsoft and only supports up to the 521-byte limit.

However, the maximum BTU length for an SDLC connection is dependent on the interface used by the link service of the SDLC adapter OEM (Original Equipment Manufacturer). Some adapters support up to 2,048 bytes for a BTU length. In these instances, the adapter manufacturer is not using the IBM SDLC Dumb interface (Ibmsdlc.dll) for the link service. The OEM is providing its own link service for this purpose as well as other features.

MORE INFORMATION

Even though the graphical user interface (GUI) allows for an entry above the 521-byte limit, this is not an indication of support beyond this limit. If such a limit were written into the GUI for MAX BTU, third-party developers would have to provide a unique solution to circumvent such a limitation. Therefore, there is no apparent limitation set by the GUI for MAX BTU.

REFERENCES

For additional information, please see the Software Development Kit (SDK) for SNA Server and the SNA Device Interface Specification (SNADIS) located in the documentation of your SNA Server CD.
Modification Type:MajorLast Reviewed:5/19/2005
Keywords:kbinfo KB236105
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