VOIP, GSM and 3G Call Flows
- SIP and H.323 Call Flow Diagrams
- GSM Circuit Switched Call Flows
- GSM Handover Call Flows
- GSM GPRS Sequence Diagrams
- 3G UMTS Sequence Diagrams
- ISDN User Part (ISUP) Call Flows
- V5.2 Protocol Call Flows
- SIGTRAN flows
The call flow diagrams were generated using EventStudio System Designer.
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.
SIP Originating Call with Authentication
SIP originating call flow. The call flow includes the authentication procedure between the SIP client and server. All messsages in this flow can be clicked to access complete message structure.
GSM Circuit Switched Call Flows
GSM Network Example
This 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 Flow - Explore More
GSM call setup is analyzed in detail. The role of each participant is documented with a separate call flow.
GSM Location Update - Explore More
GSM Location Update analyzed in detail. The role of each participant is documented with a separate sequence diagram.
GSM Mobile Terminated Call Flow
In 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 Mobile Originated SMS Session
This scenario describes the session setup for a GSM originating SMS. This sequence diagram describes the SMS signaling and data transfer between the mobile subscriber and the SMS service center.
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 Flow
This call flow describes the handover between two cells handled by different MSCs.
GSM GPRS Sequence Diagrams
GPRS Combined Attach and PDP Context Activation
The combined attach and PDP context activation of a Class B GPRS terminal will be covered here.
New SGSN Interfaces Attach and Activation
Sequence diagram listing all the interactions involving the new SGSN.
3G UMTS Sequence Diagrams
3G UMTS Originating Call
Mobile originated 3G call that details RANAP and RRC signaling. Just click on RANAP messages to get full field level 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.
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.