MAX_COMPRESSION_LEVEL


The Communications Server icon
 The MAX_COMPRESSION_LEVEL parameter keyword applies to Communications Server only.
Required? Yes
Keyword Type Enumerated
Default LZ10
Multiples Allowed? No
   MAX_COMPRESSION_LEVEL = (
      @TYPE = ENUMKEYWORD
      @ENUM_LIST = (
         NONE = 0
         RLE = 1
	       LZ9 = 2
	       LZ10 = 4
      )
      @REQUIRED = 1
      @DEFAULT = LZ10
      @READ_ONLY = 1
      )
The MAX_COMPRESSION_LEVEL parameter specifies the maximum compression level supported by this node. Valid values are:
NONE
This node does not support compression.
RLE
This node supports RLE compression.
LZ9
This node supports RLE and LZ9 compression.
LZ10
This node supports RLE, LZ9, and LZ10 compression.

This parameter is required. The default is LZ10.

SNA session level compression implements data compression in the LU-LU half session. With Communications Server for Windows®, data compression is available to all supported LU types: LU types 0, 1, 2, 3, and 6.2. Data compression provides these advantages:
  • More efficient transmission of data across low speed connections
  • More cost effective transmission of data across certain types of links where costs are determined by number of packets or amount of data transmitted, as with some X.25 links
  • Application programs do not have to provide their own compression logic.

Communications Server for Windows® supports SNA session level data compression with RLE (Run Length Encoding) compression for all LU types. RLE is the simplest and most commonly used algorithm, replacing strings or identical bytes with shorter encoded strings. Also, for LU0–3 sessions, the LZ-9 compression algorithm is supported when requested by the host.