Inside Macintosh: Networking With Open Transport / Part 1 - Open Transport Essentials

Chapter 16 - AppleTalk Data Stream Protocol (ADSP)

This chapter describes the programming interface to Open Transport's implementation of the AppleTalk Data Stream Protocol (ADSP). It explains how you can use ADSP to establish a session to exchange a stream of data between two network processes or applications in which both parties have equal control over the communication. ADSP offers a connection-oriented transactionless service that is particularly well suited to the transfer of large amounts of data.

You should read this chapter if you want to write an application that uses ADSP to exchange a stream of data between two equal parties who can each send and receive data. This chapter explains how you

• create an endpoint that listens passively for incoming connection requests

• send and receive data via ADSP

• divide an ADSP data stream into discrete logical units

• use expedited attention messages with ADSP

This chapter begins with a description of ADSP and the services that it provides under Open Transport. The section "Using General Open Transport Functions With ADSP" then gives detailed information about how ADSP client applications use the endpoint functions that Open Transport provides for connection-oriented transactionless protocols. For a more detailed explanation of endpoints and their functions, read the chapter "Endpoints".

For reference information about ADSP options, see "ADSP Reference". For an overview of ADSP and how it fits within the AppleTalk protocol stack, read the chapter "Introduction to AppleTalk", which also introduces and defines some of the terminology used in this chapter. ADSP under Open Transport conforms to the detailed specifications in Inside AppleTalk, second edition. See that book for further information about the features mentioned here.

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Chapter Contents

About ADSP

Using ADSP

Binding ADSP Endpoints

Sending and Receiving ADSP Data

The End-of-Message Option

The Checksum Option

Sending Expedited Data

Disconnecting

Using General Open Transport Functions With ADSP

OTBind

OTConnect

OTRcvConnect

OTListen

OTAccept

OTSnd

OTRcv

OTSndDisconnect

OTRcvDisconnect