Table of Contents
FOREWORD
CONTENTS
Datacompressionprocedures
1Scope
1.1General
1.2Requirementsforerror-correctingprocedures
1.3ADCEemployingdatacompression
2References
3Definitions
4Abbreviations
5FunctionaldescriptionofaDCE
5.1General
5.2DTE/DCEinterchangecircuits
5.3Signalconverter
5.4Controlfunction
5.5Error-controlfunction
5.6Datacompressionfunction
6Proceduresofthedatacompressionfunction
6.1Overviewofthedatacompressionfunction
6.2Dictionarystructure
6.3Encoding
6.4Decoding
6.5Transparentmode
6.6Transfer
7Operationsofdatacompression
7.1Communicationbetweenthecontrolanddatacompression
functions
7.2Communicationsbetweenpeerdatacompressionfunctions
7.3NegotiationofV.44capability
7.4Negotiationofdatacompressionparameters
7.5Initializationofthedatacompressionfunction
7.6Establishmentoferror-controlledconnection
7.7TransferofdatabetweentheDTE/DCEinterfaceandthedata
compressionfunction
7.8Encoding
7.9Transferofdatabetweenthedatacompressionfunctionand
theerror-controlfunction
7.10Decoding
7.11Autonomousadjustments
7.12Dictionaryreinitialization
7.13ExpediteddatatransferandFLUSH
7.14ESCAPEcommandsequence
7.15ActionondetectionofC-ERROR
8Parameters
ANNEXA-XIDinformationfieldfornegotiatingV.44capability
whenusedwithV.42
ANNEXB-OperationofV.44inPacketNetworks
B.1PacketmethodoperationofV.44
B.2Multi-packetmethodofoperationofV.44
APPENDIXI-NotesonImplementation
I.1SelectionofN2:thetotalnumberofcodewords
I.2SelectionofN7:maximumstringlength
I.3SelectionofN8:datastructuresandlengthofhistory
I.4EfficientcompressionofUnicodedata
I.5Applicabilityoftransparentmode
I.6Calculationofcompressionperformance
I.7DifferencesbetweenV.44andV.42bis
APPENDIXII-IllustrationofoperationofV.44algorithm
II.1Compressionanddecompressionof"ABCDEXABCDEYABCDEFFHAC"
II.2Compressiondecompressionof"CCCCCCCCCCX"
Bibliography Abstract
Describes a data compression algorithm for use in DCEs. It achieves a better performance than V.42 bis on many types of data. In addition to the normal stream method, the algorithm has a method which can compress data already contained in packets in an efficient way.
