Table of Contents
1Scope
2Transportservice
2.1Transportserviceobjectives
2.2Generalstructureofthetransportservice
3Transportserviceimplementationfordifferenttypes
ofnetworks
3.1TerminalsconnectedtoaPSPDN
3.2TerminalsconnectedtothePSTN
3.3TerminalsconnectedtoaCSPDN
3.4TerminalsconnectedtoanISDN
4Interworkingbetweennetworks
5Transportlayerprocedure
5.1Transportfunctions
5.2Descriptionofconnectionestablishmentand
terminationprocedures
5.3Descriptionofdatatransferprocedures
5.4Treatmentofprocedureerrors
5.5Formats
AnnexA
A.1Transportandnetworkservice
A.2Statetransitiondiagramsforthebasictransport
layerprocedures
AnnexB
B.1Statetables
B.2Listsofevents,actionsandconditions
AnnexC-Recommendationsforimplementationof
RecommendationX.21
C.1General
C.2Receiptofcallprogresssignals01or04
C.3Receiptofcallprogresssignal03
C.4Receiptofcallprogresssignalsofthegroup2to8
AnnexD-Servicedefinitionsandstatetransitiondiagrams
fortheHDLCprocedureandthenetworklayer
definedforCSPDN
D.1Servicedefinitions
D.2StatetransitiondiagramsHDLC
D.3Summaryofframedefinitions
D.4X.21service,controlledbythenetworklayer