TCP/IP and IMS Sequence Diagrams
- IP - Internet Protocol
- TCP - Transmission Control Protocol
- HTTP Sequence Diagrams
- TCP Applications
- VOIP Call Sequence Diagrams
- IMS Sequence Diagrams
- SIGTRAN Protocols
- IP Routing Protocols
The sequence diagrams were generated using EventStudio System Designer.
IP - Internet Protocol
- IP Routing and Subnets This article describes the basics of IP routing. We will consider the example of a simple network and trace the life of a packet as it gets routed from one node to another.
- ICMP Sequence Diagram Ping is a popular application used to check the presence of another node. Ping uses the ICMP Echo and Echo Reply handshake message for this purpose
- ARP Sequence Diagram ARP (Address Resolution Protocol) is responsible for mapping from IP addresses to MAC address on Ethernet.
- BOOTP Sequence Diagram The Bootstrap Protocol (BOOTP) enables a host to boot from ROM and request it's own IP address, a gateway address and a boot file name. The boot file is used to load the disk image into RAM.
- DHCP Sequence Diagram Dynamic Host Configuration Protocol (DHCP) is used to dynamically provide IP addresses and configuration information to client nodes.
- ICMP Sequence Diagram This sequence diagram describes mounting, opening and reading of a file via the NFS (Network File System).
TCP - Transmission Control Protocol
- TCP Connection Sequence DiagramsThe sequence diagrams presented here describe the 3-way handshake setup and release of a TCP connection. The byte level sequence numbers and TCP Ack handling is also shown.
- TCP Slow Start Sequence Diagrams Analyse "Slow start" congestion control mechanisms built right into TCP. As the name suggests, "Slow Start" starts slowly, increasing its window size as it gains confidence about the network's throughput.
- TCP Congestion Avoidance Sequence Diagrams Once cwnd is greater that ssthresh, TCP enters the congestion avoidance mode of operation. In this mode, the primary objective is to maintain high throughput without causing congestion. If TCP detects segment loss, TCP reduces its data flow rate by reducing cwnd. After reducing cwnd, TCP goes back to slow start
- TCP Fast Retransmit and Fast Recovery Sequence Diagram Fast Retransmit and Recovery detect a segment loss via duplicate acknowledgements. When a segment is lost, TCP at the receiver will keep sending ack segments indicating the next expected sequence number. This triggers fast recovery at the transmitter.
HTTP Sequence Diagrams
- HTTP Sequence Diagram HTTP sequence diagram for loading of the EventHelix.com home page. The page load is captured in two threads. The sequence diagrams for individual threads are also included.
- Web Caching and Refresh Sequence Diagram This sequence diagram tutorial describes the web caching feature on the web browser side. HTTP primitives that facilitate the implementation of web browser level caching are shown using an example.
- Web Page Redirection Sequence Diagram The interactions involved in web page redirection using HTTP 302 code are covered here.
- HTTP Post Sequence Diagram HTTP Post handling and lower level TCP interactions are shown in this diagram.
TCP Applications
- FTP Sequence Diagram Here we explore the sequence of interactions in a typical FTP (File Transfer Protocol) session. Individual sequence diagrams for interactions on Port 20 and 21 are also included.
- Telnet Sequence Diagram Telnet sequence covers terminal option negotiation and server handling.
- SMTP E-Mail Sequence diagram describing SMTP e-mail send. DNS MX record interactions are also covered.
- POP3 Sequence Diagram Interactions between a POP3 server and client are described here.
- SSL Sequence Diagram Message sequence diagram describing the setup of a SSL secure connection.
VoIP Call Sequence Diagram
- 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) Sequence Diagrams
- 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.