GSM, SIP, H.323, ISUP and IMS Call Flows
- GSM Circuit Switched Call Flows
- GSM Handover Call Flows
- GSM GPRS Sequence Diagrams
- SIP and H.323 Call Flow Diagrams
- IMS Call Flows
- LTE/SAE Call Flow Diagrams
- ISDN User Part (ISUP) Call Flows
- V5.2 Protocol Call Flows
The call flow diagrams were generated using EventStudio System Designer.
GSM Circuit Switched Call Flows
- GSM Network ExampleThis example shows a few cells in a GSM network. We will be referring to this diagram in several sequence diagrams and call flows.
- GSM Mobile Originated Call FlowA detailed call flow of a GSM mobile originated call.
- GSM Mobile Originated Call Flow - Explore MoreGSM call setup is analyzed in detail. The role of each participant is documented with a separate call flow.
- GSM Location Update Sequence DiagramHow does the cellular provider know where you are? Here we look at the location updating procedure initiated by mobiles to keep the cellular provider updated on their current location.
- GSM Location Update - Explore MoreGSM Location Update analyzed in detail. The role of each participant is documented with a separate sequence diagram.
- GSM Mobile Terminated Call FlowIn this call flow we will look at how a terminating call is handled in GSM. Setting up a terminating call is a two step process. (1) Interrogation procedure to locate the subscriber (2) Actual call setup after the subscriber has been located.
- GSM RR Call FlowsGSM Radio Resource Management (RR) Call Flows.
- GSM RR Collaboration DiagramGSM Radio Resource Management (RR) Collaboration Diagram.
- GSM MM Call FlowsGSM Mobility Management (MM) Call Flows.
- GSM MM Collaboration DiagramGSM Mobility Management (MM) Collaboration Diagram.
GSM Handover Call Flows
- GSM Handover Call Flow (Intra MSC)This call flow covers a simple case of call handover in GSM. Here a user has an active call and is moving from the Rockville Cell to the Bethesda Cell.
- GSM Inter-MSC Handover Call FlowThis call flow describes the handover between two cells handled by different MSCs.
- GSM Inter-MSC Handover Call Flow (Explore More)Inter MSC handover is analyzed in detail. The role of each participant is documented with a separate call flow.
GSM GPRS Sequence Diagrams
- GPRS Combined Attach and PDP Context ActivationThe combined attach and PDP context activation of a Class B GPRS terminal will be covered here.
- New SGSN Interfaces Attach and ActivationSequence diagram listing all the interactions involving the new SGSN.
- User Terminal Interfaces in Attach and PDP ActivationSequence diagram summarizing the user terminal interactions in attach and PDP context activation.
SIP and H.323 Call Flow Diagrams
- SIP to PSTN Sequence Diagram In this scenario, Alice is a SIP phone or other SIP-enabled device. Bob is reachable via the PSTN at global telephone number. Alice places a call to Bob through a Proxy Server (Proxy 1) and a Network Gateway (NGW 1).
- SIP to ISDN PBX Sequence Diagram Alice is a SIP device while Carol is connected via a Gateway (GW 1) to a PBX. The PBX connection is via a ISDN trunk group.
- H.323 Call Flow The call flow diagram presents the flow of an H.323 call. Covers: H.225/Q.931 Call Setup; H.245 Negotiation and Voice Path Setup; RTP/RTCP Based Voice Communication
IP Multimedia Subsystem (IMS) Call Flows
- IMS Registration An IMS terminal accesses the home IMS via a visited IMS. Unauthenticated registration followed by authenticated registration is covered here.
- IMS to IMS Call Flow Call flow for an IMS subscriber to another IMS subscriber is covered here.
- PSTN to IMS Call A ISUP to IMS call flow is described here. Megaco/H.248 interactions and ISUP-SIP interworking are covered in detail.
- IMS to PSTN Call Here we explore an IMS to PSTN terminating call. The call flow covers the IMS-ISUP interworking and Megaco/H.248 interactions between the MGCF and IM-MGW. Call routing via the BGCF is also illustrated.
- SDP Codec Selection and QoS Signaling in an IMS callAn IMS call is analyzed with a focus on the SDP interactions involved in codec selection and QoS.
- IMS Presence Subscription and NotificationIP Multimedia Subsystem (IMS) provides a framework for building advanced telecom services. One such service is network wide publication and subscription of presence information.
- IMS Presence Resource List Subscription and NotificationThis scenario describes how a user can subscribe to a predefined list of subscribers via a Resource List Server. The RLS handles the interactions needed for presence subscription for individual users on that list.
- IMS Conference CallSetup of an IMS conference call with REFER based invitation to other subscribers.
- IMS Push-to-talk Sequence Diagram - Pre-established SessionPush-to-talk communication between IMS users that have pre-established a session.
LTE/SAE Call Flow Diagrams
- LTE/SAE Attach Sequence DiagramThis flow describes the LTE/SAE terminal attach. The terminal is attaching in a new MME.
- LTE/SAE Tracking Area Update Sequence DiagramTracking area update of an LTE/SAE terminal is covered here. The tracking update results in a serving gateway change.
- LTE Encryption and Integrity Protection FlowLTE presentation and call flows cover the security session setup. The keys used in LTE are described in detail.
ISDN User Part (ISUP) Call Flows
- SS7 ISUP to ISUP Call (Called Subscriber Clears First)An ISUP Incoming to ISUP Outgoing transit call is covered here. Call is released first by the called subscriber.
- SS7 ISUP to ISUP Call (Calling Subscriber Clears First)An ISUP Incoming to ISUP Outgoing transit call is covered here. Call is released first by the calling subscriber.
- SS7 ISUP to ISUP Call (Failure Scenario)An ISUP Incoming to ISUP Outgoing transit call is covered here. Call is released on receipt of call failed indication from called side.
V5.2 Protocol Call Flows
- V5.2 to V5.2 Call (DTMF, Called Subscriber Goes Onhook)Setup and release of a V5.2 subscriber to V5.2 subscriber call. Calling subscriber uses DTMF dialing and the called subscriber goes onhook.
- V5.2 to V5.2 Call (Pulse, Calling Subscriber Goes Onhook)Setup and release of a V5.2 subscriber to V5.2 subscriber call. Calling subscriber uses pulse dialing and calling subscriber clears first.