A/UX® System Administrator's Reference Sections 1M, 7, and 8

appletalk(7) appletalk(7)
NAME
appletalk - general AppleTalk socket interface and
STREAMS controls
DESCRIPTION
This manual page describes the AppleTalk I/O control calls (see
ioctl(2», device files, and the general nature of the NUX AppleTalk
interface.
1
Before beginning, several points should be noted. The AppleTalk
library routines automatically set up and invoke the correct ioctl
requests that are necessary for most AppleTalk requirements.
While the ioctls give the programmer more control than the AppleTalk
library routines, they require a much greater understanding
of the NUX implementation of AppleTalk. In addition, AppleTalk
ioctl calls are subject to change, while AppleTalk library
functions will not change. It is, therefore, strongly recommended
that the library routines be used whenever possible instead of the
more complicated ioctl calls.
AppleTalk Protocols
AppleTalk is implemented as a protocol stack, consisting of a set
of layers, with one or more protocols per layer. This set of protocols
corresponds roughly to the layers of the Open Systems Interconnection
(OSI) reference model published by the International
Standards Organization (ISO). Each layer is built on top of (and
uses) the previous layer. The order of layers, from lowest (closest
to the physical transport) to highest (closest to the application), is
as follows:
Link layer AppleTalk Link Access Protocol (ALAP)
Network layer
Transport layer
Session layer
Datagram Delivery Protocol (DDP)
AppleTalk Transaction Protocol (AlP)
Name Binding Protocol (NBP)
Routing Table Maintenance Protocol
(RTMP)
Zone Information Protocol (ZIP)
Printer Access Protocol (PAP)
The lower layers (ALAPIDDP) are normally used for new network
testing and development, such as building a new layer using
TCP/IP on top of DDP.
February, 1990
RevisionC