Compression Transformation Clause Samples

Compression Transformation. The compression transformation shall result in either compressed or uncompressed data. When a user data PDU arrives, it shall be assigned to a particular context and processed according to ANSI X3.241-1994 to form compressed data or used as is to form uncompressed data. Prior to the compression transformation, if a Reset-Request is outstanding for the context to be used, the history buffer shall be cleared. In performing the transformation, if P-Process-Mode = “Compressed-Only”, the history buffer shall only be updated if the result is compressed data. If P- Process-Mode = “Compressed+Uncompressed” the history buffer shall be updated when either compressed data or uncompressed data is produced. Uncompressed data may be sent at any time. Uncompressed data shall be sent if the compression transformation causes enough expansion to cause the frame size to exceed the maximum frame relay information field size. If P-Process-Mode = “Compressed-Only” and the encoder has modified the history buffer before sending an uncompressed DCP data PDU, the history buffer shall be cleared or restored to its previous state before the next user data PDU is processed. Note: The maximum expansion of the ANSI X3.241-1994 algorithm is 12.5%.