3G UMTS Originating Call Overview PDF - EventHelix.com

Component Interfaces (Originating Call)User Equipment UTRAN Core Network 06-Oct-13 07:24 (Page 1)A 3G-UMTS originating call is described here. Setup radio bearers and RANAP signaling are covered in detail. You can clickon most RANAP messages to see the full content of the message.This call flow has been generated with from a Wireshark PCAP file using VisualEther (http://www.eventhelix.com/VisualEther/).The generated call flow was later modified with EventStudio (http://www.eventhelix.com/EventStudio/) to add comments andterminal level interactions.3G Call SetupRRC Connection SetupRRC Connection RequestrrcrrcUE Identity,UE Capabilities,Establishment CauseRRC Connection SetuprrcrrcTransport Channel Information,Signaling Radio BearerRRC Connection CompleterrcrrcCiphering InformationUE wishes to establish a voice call so it requests aRadio Resource Control (RRC) connection.The RNC accepts the RRC Connection Requestand assigns a traffic channel. The message alsocreates a Signaling Radio Bearer (SRB).The UE responds back to signal the completion ofthe RRC Connection Setup.CM Service RequestInitial UE Message [CM Service Request]rrcrrcDTAP MM CM Service RequestranapranapBCD Digits : 123456780000000SCTP SACKSCCP Connection ConfirmSCTP SACKAuthentication ProcedureThe mobile sends an Initial UE Message thatcarries the CM Service Request as a NAS (NonAccess Stratum) payload.The CM Service Request is the first message to bereceived for the call from the RNC. This messagealso sets up the SCCP connection between theRNC and the Core Network.The "CM Service Request" also marks the start ofan Iu connection.The Core Network sends an SCTP level ack forthe CM Service Request message.SCCP connection setup is confirmed.SCTP ack for SCCP Connection Confirmmessage.Core Network decides that the terminal needs to be authenticated.DTAP MM Authentication RequestranapranapDownlink Direct Transfer [DTAP MM Authentication Request]rrcrrcUplink Direct Transfer [DTAP MM Authentication Response]rrcrrcThe Authentication Request is carried as NASpayload in a Downlink Direct Transfer RRCmessage.The Authentication Response is carried as NASpayload in a Uplink Direct Transfer RRC message.DTAP MM Authentication Responseranapranap

Component Interfaces (Originating Call)User Equipment UTRAN Core Network 06-Oct-13 07:24 (Page 2)RANAP CommonIDIMSI is sent to the RNC.ranapranapid : id-PermanentNAS-UE-ID(23)Security ProcedureSCTP SACKSCTP level ack for Command ID.Core Network sends new keys for ciphering and integrity protection.RRC Security Mode CommandrrcrrcCN domain,UIA,UEA,FRESH,Secu rity Capability,MAC-ISecurity Mode CommandranapranapUIAs,IK,UEAs,CKCore Network initiates ciphering and integrityProtection. The "MSC/VLR" sends the SecurityMode Command message to RNC.The RNC generates the RRC message Securitymode command. The message includes the UEsecurity capability, the ciphering capability, the UIAand FRESH to be used and if ciphering shall bestarted also the UEA to be used. This is the firstmessage to be integrity protected. It contains theMAC-I integrity protection "checksum".RRC Security Mode CompleterrcrrcSecurity Mode CompleteranapranapDTAP MM CM Service AcceptranapranapSCTP SACKDownlink Direct Transfer [CM Service Accept]rrcrrcThe Core Network accepts the service request.Ack for "MM CM Service Accept".RNC carries the CM Service Accept as a NASpayload.Call Connection SetupUplink Direct Transfer [DTAP CC Setup]rrcrrcCall Setup is received as a NAS payload.ranapDTAP CC Setupranap.... 0001 = Numbering planidentification : ISDN /TelephonyNumbering (Rec ITU -T E.164)(0x01),BCD Digits : 5Call Setup request is received from the RNC.SCTP SACKDTAP CC Call ProceedingranapranapSCTP SACKDownlink Direct Transfer[DTAP CC Call Proceeding]rrcrrcAck for call setup request."Core Network" signals that the call setup isproceeding.SCTP ack for call proceeding.The call proceeding message is wrapped in aDownlink Direct Transfer and sent to the UE.

Component Interfaces (Originating Call)User Equipment UTRAN Core Network 06-Oct-13 07:24 (Page 3)RAB AssignmentRANAP RAB -Assignmentid : id -RAB -SetupOrModifyList,id : id -RAB -SetupOrModifyItem,id : id -Alt -RAB -ParametersCore Network initiates a Radio Access Bearer(RAB) Assignment. The message specifies theQuality of Service parameters.SCTP SACKAck for RAB Assignment received from CoreNetwork.rrcRadio Bearer SetuprrcRadio Bearer Setup CompleterrcrrcRANAP RAB -Assignmentranapranapid : id -RAB-SetupOrModifiedList (52),id : id -RAB-SetupOrModifiedItem (51),id : id -Ass -RAB -Parameters(90)SCTP SACKRNC responds to Core Network after completingRB Setup with the Terminal.Ack for RAB Assignment response sent from RNCto Core Network.ranapDTAP CC AlertingranapAsk RNC to Notify the terminal that the subscriberis bering rung.SCTP SACKDownlink Direct Transfer [DTAP CC Alerting]rrcrrcAck to Alerting.Alert is sent to the UE.ranapDTAP CC ConnectranapNotify the RNC that the called subscriber hasanswered.SCTP SACKDownlink Direct Transfer[DTAP CC Connect]rrcrrcAck for Connect.Uplink Direct Transfer[DTAP CC Connect Acknowledge]rrcrrcDTAP CC Connect AcknowledgeranapranapSCTP SACKRNC responds back with completion of connect.Ack for Connect Acknowledge.ConversationrabrabrabrabConversationrabConversationrabConversationrabConversationrabVoice communication in progress.

Component Interfaces (Originating Call)User Equipment UTRAN Core Network 06-Oct-13 07:24 (Page 4)rabConversationrabCall ReleaseCall Connection ReleaseUplink Direct Transfer [DTAP CC Disconnect]rrcrrcDTAP CC Disconnectranapranap.001 0000 = Cause : (16)Normal call clearingSCTP SACKReceived call release from originating subscriberRNC sends call disconnect to the Core Network.SCTP ack for disconnect.ranapDTAP CC ReleaseranapSCTP SACKCore Network releases the session.DTAP CC Release CompleteranapranapRNC signals release complete to Core NetworkDownlink Direct Transfer [DTAP CC Release Complete]rrcrrcSCTP SACKThe call is cleared so the Iu connection can nowbe released.Iu Connection ReleaseranapRANAP Iu-Releaseranapid : id -Cause (4)Core Network initiates the Iu release.SCTP SACKranapRANAP Iu-ReleaseranapRNC signals back the release of the Iu connection.SCTP SACKRRC Connection ReleaseRRC Connection ReleaserrcrrcRRC Connection Release Completerrcrrc

Component Interfaces (Originating Call)User Equipment UTRAN Core Network 06-Oct-13 07:24 (Page 5)SCCP ReleasedSCCP connection is released as well.SCTP SACKSCCP Release CompleteSCCP connection is now released.SCTP SACKThis call flow has been generated with from a Wireshark PCAP file using VisualEther (http://www.eventhelix.com/VisualEther/).The generated call flow was later modified with EventStudio (http://www.eventhelix.com/EventStudio/) to add comments andterminal level interactions.Explore more call flow diagrams at: http://www.eventhelix.com/realtimemantra/telecom/