SLI Rules

  1. To allow the SLI application to handle the compression and decompression of data:
    • The SLI application must supply a BIND Callback routine when it issues the SLI_OPEN verb.
    • When the SLI application's BIND callback routine is started, SLI receives the BIND request that has bits 6 and 7 of Byte 25 set to indicate compression is offered or requested.
    • The SLI application should return the BIND response with bits 6 and 7 of Byte 25 set to indicate "offered or mandated compression accepted".
  2. To allow Communications Server to handle compression on behalf of SLI:
    • Use the Communications Server SNA Node Configuration utility to indicate that the node supports compression by doing the following:
      • Select Configure Node
      • Select Advanced
      • Set maximum compression level supported by node to RLE
    • If the application did not supply a BIND callback routine on the SLI_OPEN verb, SLI will by default set the BIND response to indicate that Communications Server will compress and decompress the data for SLI.
    • If the application did supply a BIND callback routine:
      • When the BIND callback routine is started, it receives the BIND request that has bits 6 and 7 of Byte 25 set to indicate compression is offered or requested.
      • The SLI application returns the BIND response with bits 6 and 7 of Byte 25 set to indicate "no compression". Communications Server intercepts and modifies the BIND response, and compresses and decompresses the data to the host.