Time-Sequence Diagrams

Table Of Contents

Time-Sequence Diagrams

Overview

Diagram Labelling

Synchronous and Asynchronous Modes

Completion and Error Events

Diagrams

Local Endpoint Management (Initialization)

Client Connect Sequence (Accepted)

Client Connect Sequence (Rejected)

Server Connect Sequence (Accepted)

Server Connect Sequence (Rejected)

COTS Receive Data Sequence

COTS Send Data Sequence

CLTS Receive Data Sequence

CLTS Send Data Sequence

CLTS Datagram Error Sequence

Orderly Release Sequence

Abortive Disconnect Sequence

Simultaneous Disconnects

Local Endpoint Management (Termination)

Time-Sequence Diagrams

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This appendix contains sequence diagrams showing the relationship between the API service requests issued at an endpoint and service primitives issued to or by the transport provider. It includes these sections:

•Overview

Describes the labelling and illustration techniques used in the diagrams.

•Diagrams

Includes the time-sequence diagrams.

Overview

Each time-sequence diagram shows a local transport user (Local TU) issuing requests and responding to events at the local transport interface (API), and a transport provider (TP) receiving request and response primitives, and issuing indication and confirm primitives.

Diagram Labelling

The transport provider is shown as a single entity, although, in actuality, there is a local and remote entity between which the protocol exchanges take place. Also, the transport interface between the remote transport provider and the peer transport user (Remote TU) is not shown.

The vertical lines delineating the transport provider represent the Transport Service Access Points (TSAPs) for the local and remote transport user. The vertical lines delineating the transport interface represent the endpoint from the perspective of the transport user and transport provider.

All interactions between the local transport user and the API are shown in terms of the service functions executed, and their normal or abnormal completions:

•The invocation of a function is labeled a request

•Its successful completion is simply labeled a completion

•An abnormal completion is indicated by error

•An asynchronous event that causes an exit routine to be scheduled is labeled an indication.

Synchronous and Asynchronous Modes

Some sequences are shown in synchronous and asynchronous mode:

•Synchronous mode applies when service requests are issued synchronous with normal application program processing. Generally, the application program is running under control of a PRB.

•Asynchronous mode applies when service requests are issued asynchronous with normal processing. This mode requires use of exit routines, and requests are often issued under control of the IRB that runs the exit routine.

In synchronous mode, the time relationship between the occurrence of an event (for example, the arrival of some data) and invocation of the corresponding service function (for example, TRECV) is unimportant. However, in asynchronous mode, the service function is generally issued in response to the event.

Completion and Error Events

Completion and error events occur when a TCHECK control function is executed. The TCHECK function may be executed by the API (OPTCD=SYNC) or the transport user (OPTCD=ASYN).

Diagrams

This section includes the time-sequence diagrams.

Local Endpoint Management (Initialization)

Client Connect Sequence (Accepted)

Synchronous Mode

Asynchronous Mode

Client Connect Sequence (Rejected)

Synchronous Mode

Asynchronous Mode

Server Connect Sequence (Accepted)

Synchronous Mode

Asynchronous Mode

Server Connect Sequence (Rejected)

Synchronous Mode

Asynchronous Mode

COTS Receive Data Sequence

Synchronous Mode

Asynchronous Mode

COTS Send Data Sequence

TLI Mode

Socket Mode

CLTS Receive Data Sequence

Synchronous Mode

Asynchronous Mode

CLTS Send Data Sequence

CLTS Datagram Error Sequence

Synchronous Mode

Asynchronous Mode

Orderly Release Sequence

Receive Path - Synchronous Mode

Receive Path - Asynchronous Mode

No Receive Data - Synchronous Mode

Send Path

Abortive Disconnect Sequence

Locally Initiated

Remotely Initiated

Simultaneous Disconnects

Transparent

Non-Transparent

Local Endpoint Management (Termination)