Inside Macintosh: Networking /

Chapter 1 - Introduction to AppleTalk

Deciding Which AppleTalk Protocol to Use

The AppleTalk Manager consists of a collection of application programming interfaces
to the AppleTalk protocols and the LAP Manager. Each of the AppleTalk protocols implements a different set of functions and services, and the programming interface for a specific protocol includes a set of routines that give your application access to the protocol's functions and services.

AppleTalk offers programming interfaces to a variety of communications protocols at different levels. Your choice of protocol or protocols to use depends primarily on your application's needs.

This section provides a brief discussion of how your application can use each protocol. The AppleTalk protocols are layered in a stack with each protocol benefiting from the services of the protocols in layers below it. Looked at from a top-down approach, the high-level protocols provide an accretion of all the services of the underlying protocols.

A developer who uses the higher-level protocols that provide for reliable delivery of data and error recovery does not have to implement these services as part of an application. An application developer who wants to write a program for end users
that runs on an AppleTalk network would typically use the interfaces to one or more higher-level protocols. For example, you might use NBP to register the program with the network so that it is visible to users and other applications, and, perhaps, ADSP to transfer data.

A network software developer who wants to implement a custom session-oriented protocol, instead of using ADSP or ASP, would typically use the interface to a protocol such as DDP or any of the protocols below it. A network software developer who wants to implement a custom protocol stack instead of using AppleTalk can use a low-level protocol interface to attach a protocol handler that receives data from the network.

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Subtopics

Making Your Application Available Throughout the Internet

Identifying Zones

Using a Session Protocol to Send and Receive Data

Performing a Transaction

Sending and Receiving Data as Discrete Packets

Measuring Packet-Delivery Performance

Accessing AppleShare and Other File Servers

Receiving Packets Using a Virtual Node and Processing Them in a Custom Manner

The LAP Manager

Directly Accessing a Driver for a Network Type