3G UMTS Mobile Terminating Call (SequenceProject) A 3G-UMTS

3G UMTS Mobile Terminating Call (SequenceProject)User

EquipmentUE-RNC Sessions UTRAN RNC-Core Network Sessions Core Network

UE RNC MSC/VLR

EventStudio System Designer 6

09-Feb-14 19:43 (Page 1)

A 3G-UMTS terminating 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.

ranap ranap

RANAP Paging

DomainIndicator = CS-Domain,PermanentNAS-UE-ID = IMSI

MSC/VLR sends a Pagemessage for the terminatingcall. The message containsthe IMSI for the subscriber.

SCTP SACK SCTP ack for the pagingmessage.

Core Network Pages UE

rrc rrc

RRC Connection Request

UE Identity,UE Capabilities,Establishment Cause

UE wishes to establish avoice call so it requests aRadio Resource Control(RRC) connection.

rrc rrc

RRC Connection Setup

Transport Channel Information,Signaling Radio Bearer

The RNC accepts the RRCConnection Request andassigns a traffic channel.The message also creates aSignaling Radio Bearer(SRB).

rrc rrc

RRC Connection Complete

Ciphering Information

The UE responds back tosignal the completion of theRRC Connection Setup.

RRC RRC Connection Setup hasbeen completed between theUE and the RNC. SignalingRadio Bearer (SRB) is alsocreated at the time of theRRC connection setup.

RRC Connection Setup

rrc rrc

Initial UE Message [Page Response] The mobile sends an InitialUE Message that carries thePage Response as a NAS(Non Access Stratum)payload.

Page Response and Initial Call Handshake

http://www.eventhelix.com/umts/terminating-call/details/3.htm




UE RRC RNC MSC/VLR


09-Feb-14 19:43 (Page 2)

ranap ranap

RANAP Initial UE Message [DTAP Page Response]

LAI,PLMN identity,Mobile Country Code (MCC),Mobile Network Code (MNC),Global RNC-ID,IMSI,Mobile Station Classmark

The Page Response is sentin a RANAP message.

SCTP SACK

sccp sccp

SCCP Connection Confirm SCCP connection setup isconfirmed.

SCTP SACK

SCCP The SCCP connection hasbeen established betweenthe RNC and the CoreNetwork.

Iu An Iu signaling connection isnow active between the RNCand the Core Network.

ranap ranap

RANAP DirectTransfer [DTAP Setup]

NAS-PDU,SAPI

The MSC sends a Setupmessage as NAS payload ina Direct Transfer message.

SCTP SACK

rrc rrc

Downlink Direct Transfer [DTAP Setup] Send the Setup message tothe UE.

rrc rrc

Uplink Direct Transfer [DTAP Call Confirmed] Call Confirmation is receivedas a NAS payload.

ranap ranap

RANAP DirectTransfer [DTAP Call Confirmed]

Bearer Capability,Supported Codec List

Call Confirmed messagewith Bearer and Codecinformation is sent from theRNC to the MSC/VLR.

SCTP SACK

ranap ranap

RANAP RAB Assignment Request

RAB-SetupOrModifyList,RAB Id,RAB-SetupOrModifyItem,GuaranteedBitrate: 12200

Core Network initiates aRadio Access Bearer (RAB)Assignment. The messagespecifies the Quality ofService parameters.

SCTP SACK

rrc rrc

Radio Bearer Setup Setup the Radio Bearer toassign circuit switchedresources to the voice call.

rrc rrc

Radio Bearer Setup Complete Terminal responds back.

RAB Assignment













UE RRC RNC SCCP Iu MSC/VLR


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RB Radio Bearer has now beenestablished between the UEand the RNC.

ranap ranap

RANAP RAB Assignment Response

RABSetupOrModifiedList,SetupOrModifiedItem,RAB Parameters,GuaranteedBitrate: 12200

RNC responds to CoreNetwork after completing RBSetup with the Terminal.

SCTP SACK

RAB The voice radio accessbearer has beensuccessfully created.

beginbeginRinging Called

Subscriber

The called subscribersphone is now ringing.

Ring

rrc rrc

Uplink Direct Transfer [DTAP Alerting] The called subscribersphone is now ringing.

ranap ranap

RANAP DirectTransfer [DTAP Alerting] Notifiy the Core Network thatthe called subscriber is beingrung.

SCTP SACK

Alerting

Waiting for the calledsubscriber to answer thecall.

Answer call

endendRinging Called

Subscriber

rrc rrc

Uplink Direct Transfer [DTAP Connect] Notify that the calledsubscriber has answered thecall.

ranap ranap

RANAP DirectTransfer [DTAP Connect] Notify the MSC/VLR that thecall has been answered.

SCTP SACK

ranap ranap

RANAP DirectTransfer [DTAP Connect Acknowledge] Core Network acknowledgesthe call connect.

SCTP SACK

rrc rrc

Downlink Direct Transfer [DTAP Connect Acknowledge] The RRC layer transportsthe Connect Acknowledge tothe UE.

Called subscriber answers the call











UE RRC RB RNC SCCP Iu RAB MSC/VLR


09-Feb-14 19:43 (Page 4)

Voice Path Voice path is now activebetween the User Terminaland the Called Subscriber.

rab

Conversationrab

Voice communication inprogress.

rab

Conversationrab

rab

Conversationrab

rab

Conversationrab

rab

Conversationrab

Conversation

ranap ranap

RANAP DirectTransfer [DTAP Disconnect] The called subscriber hasinitiated a call release. Thisresults in a Disconnectmessage from the MSC/VLRto the RNC.

SCTP SACK (3)

rrc rrc

Downlink Direct Transfer [DTAP Disconnect] RNC forwards thedisconnect to the UE.

rrc rrc

Uplink Direct Transfer [DTAP Release] UE sends the releasemessage.

ranap ranap

RANAP DirectTransfer [DTAP Release] Call release is sent to theMSC/VLR.

SCTP SACK

ranap ranap

RANAP DirectTransfer [DTAP Relesase Complete] This message signals thecompletion of call release.

SCTP SACK (3)

rrc rrc

Downlink Direct Transfer [DTAP Release Complete] RNC forwards the releasecomplete to the UE.

Called subscriber initiates a call clear

Release the Iu Connection









UE RRC RB RNC SCCP Iu RAB MSC/VLR


09-Feb-14 19:43 (Page 5)

ranap ranap

RANAP Iu-Release

Cause = Normal Release

The MSC/VLR initiates therelease of the Iu connection.

SCTP SACK

ranap ranap

RANAP Iu-Release RNC also acknowledges theIu release.

SCTP SACK

rrc rrc

RRC Connection Release

rrc rrc

RRC Connection Release Complete

RRC Connection Release

sccp sccp

SCCP Released Releasing the SCCPconnection.

SCTP SACK

sccp sccp

SCCP Release Complete Completed the release of theSCCP connection.

SCTP SACK

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.

Explore more call flow diagrams at: http://www.eventhelix.com/realtimemantra/telecom/









Documents

3G UMTS Mobile Terminating Call (SequenceProject) A 3G-UMTS