About the AppleTalk Manager-2
AppleTalk is a communications network system including personal computer
workstations, computers acting as file servers and print servers, printers,
and a variety of types of communications hardware and software. the
system for applications running on Macintosh computers.
• new routines for the .MPP, .ATP, and .XPP device drivers
• a new wildcard character for use with the Name-Binding Protocol
• a new operating-system queue, called the AppleTalk Transition Queue
• the application interface routines provided by a new AppleTalk
• The .ENET driver and the routines your application can use to
control this driver
use to send and receive information within an AppleTalk network system.
Because the AppleTalk network system includes both hardware and
but also file servers, print servers, internet routers, drivers for circuit
cards, and so forth-the information here constitutes only a small part of the
body of literature documenting AppleTalk.
For a detailed description of AppleTalk protocols, see Inside AppleTalk, second
alternate AppleTalk connections, see the Macintosh AppleTalk Connections
Programmer's Guide. To learn how to install and operate an AppleTalk internet,
see the AppleTalk Internet Router Administrator's Guide and the AppleTalk Phase 2 Introduction and Upgrade Guide. For an introduction to the hardware
and software of an entire AppleTalk network, see Understanding Computer
Networks and the AppleTalk Network System Overview. For information on designing circuit cards and device drivers for Macintosh computers, see
Designing Cards and Drivers for the Macintosh Family,second edition.
The changes to that have most recently been made to AppleTalk other than
to as AppleTalk Phase 2. (When necessary for purposes of differentiation,
the previous version of AppleTalk is referred to as AppleTalk Phase 1.) The
Phase 2 versions of the AppleTalk drivers are included as part of system
software version 7.0 and can be installed on any Macintosh computer other
than the Macintosh128K, Macintosh 512K, Macintosh 512K enhanced, and
Macintosh XL computers. If you want to provide AppleTalk Phase 2 drivers with
your product, you must obtain a license from Apple Software Licensing.
protocols to the higher-level AppleTalk protocols) and hardware device
drivers for specific data links. Software that supports AppleTalk data links is
contained in files of type 'adev', referred to as AppleTalk connection files. This
section lists the new features of AppleTalk, describes the organization of the
Changes to The AppleTalk Manager
The AppleTalk features that are new or improved include:
• a new .MPP driver function that returns information about
• a new Name-Binding Protocol (NBP) wildcard character that can
substitute for one or more characters in AppleTalk names (see A New
standard interface between the AppleTalk protocols and the data links
used by AppleTalk, such as LocalTalk, EtherTalk, and TokenTalk (see
• the AppleTalk Transition Queue, an operating-system queue that
can notify your application each time an AppleTalk driver is opened or
closed or each time certain other transitions occur
• an implementation of parts of the IEEE 802.2 protocol, which allows
you to attach and detach your own protocol handlers for EtherTalk data
• new .ATP driver functions that allow you to set a value for the .ATP
release timer and to cancel all pending asynchronous calls to the
• new .XPP driver functions that provide information from ZIP about
• improvements to the AppleTalk protocols that allow a single network,
other than LocalTalk, to contain more than one zone (see
• the AppleTalk Data Stream Protocol (ADSP), which provides
full-duplex data stream communications for use by applications (see
the section,
AppleTalk Data Stream Protocol (ADSP))
that is manufactured by Apple Computer, Inc. (for detailed
AppleTalk Protocols
• LocalTalk Link Access Protocol (LLAP)
• EtherTalk Link Access Protocol (ELAP)
• TokenTalk Link Access Protocol (TLAP)
• Datagram Delivery Protocol (DDP)
• Routing Table Maintenance Protocol (RTMP)
• appleTalk Transaction Protocol (ATP)
• Name-Binding Protocol (NBP)
• appleTalk Echo Protocol (AEP)
• Zone Information Protocol (ZIP)
• AppleTalk Session Protocol (ASP)
• AppleTalk Data Stream Protocol (ADSP)
• AppleTalk Filing Protocol (AFP)
The LocalTalk Link Access Protocol, EtherTalk Link Access Protocol,
TokenTalk Link Access Protocol, and other link access protocols provide
link hardware used by AppleTalk.
Note: The LocalTalk Link Access Protocol (LLAP) was originally called
the AppleTalk Link Access Protocol (ALAP). With the addition of the
EtherTalk Link Access Protocol (ELAP) and other link access protocols, this
protocol was renamed to indicate the specific data link it supports.
Note: The various AppleTalk protocols are sets of rules, not computer
programs, and so can be implemented in many different ways on many
different systems. All of the AppleTalk protocol functions that you can
address or control from a Macintosh application are implemented as
Macintosh device drivers or managers. Many other features of these
protocols are implemented in software located only on internet routers that
are not used to run general applications. Some parts of protocols are
implemented by server software such as file servers and print servers.
Therefore, when About The AppleTalk Manager refers to a protocol as
“doing” or “ controlling” something, you should understand the statement to
mean that some program that implements the protocol actually carries out
the operation.
As shown, a link access protocol controls the access of the node to the
network hardware and makes it possible for many nodes to share the same
communications hardware. Each link access protocol assigns a node ID to the
node and decodes the node addresses of messages it receives. A link access
protocol provides node-to-node delivery of data packets. Examples of link
access protocols include the LocalTalk Link Access Protocol, the EtherTalk Link
Access Protocol, and the TokenTalk Link Access Protocol.
Whereas earlier implementations of AppleTalk were restricted to one 16-bit
network number per network (that is, one network number for all nodes
connected with no intervening routers) and 254 nodes per network number,
AppleTalk Phase 2 allows more than one network number for each network
(other than LocalTalk, which is still limited to one network number per
network). A network of a type that allows more than one network number is
known as an extended network. Each node in an extended network must now
be specified by both its 16-bit network number and its 8-bit node ID. In
principle, each network (other than LocalTalk) can now have over 16 million
nodes. In any specific implementation, the hardware or software might limit
the network to fewer nodes.
The Datagram Delivery Protocol (DDP) provides socket-to- socket delivery of data packets within an AppleTalk internet. The address of a DDP
packet includes the socket number, node ID, and network number.
The Routing Table Maintenance Protocol (RTMP) is used by routers on an AppleTalk internet to determine how to forward a data packet to the
network number to which it is addressed. The RTMP implementation on a
router maintains a table, called a routing table, that specifies the shortest
path to each possible destination network number. The AppleTalk protocol
software in a workstation (that is, a node other than a router) contains only a
small part of RTMP, called the RTMP stub, that DDP uses to determine the
network number (or range of network numbers) of the network cable to which
the node is connected and to determine the network number and node ID of one
router on that network cable. There is no application interface to the RTMP
stub.
The AppleTalk Transaction Protocol (ATP) provides reliable delivery of data by retransmitting any data packets that are lost. ATP also ensures that
data packets are delivered in the correct sequence. ATP is a
transaction-based protocol, meaning that one socket client transmits a
request for some action and the other socket client carries out the action and
transmits a response. Although-as you can see from the AppleTalk Protocols
clients of ATP, many applications use ATP directly to transmit data over an
AppleTalk internet.
The Name-Binding Protocol (NBP) maintains a table that contains the internet address and name of each entity in the node that is visible to other
entities on the internet (that is, each entity that has registered a name with
NBP). The internet address includes the socket number, node ID, and
network number. The name consists of three fields: the object, type, and zone.
The object and type are assigned by the entity itself and can be anything the user or application assigns. A zone is a logical grouping of a subset of the nodes
on the internet. The zone field of the name is the zone in which the node resides.
NBP also allows its clients to obtain the internet address of any
network-visible entity in the internet by providing its name. NBP maps this
name to an internet address, thus providing the link between the user-supplied
name for an entity and the internet address that is used by DDP to send and
receive data packets.
The AppleTalk Echo Protocol (AEP) listens for special packets sent by other nodes and, when it receives such a packet, echoes it back to the sender.
AEP is used by some clients of DDP to determine whether another node ( known
to have AEP) can be accessed over the inter-net, and to determine how long it
takes a packet to reach another node. There is no application interface to AEP.
The Zone Information Protocol (ZIP) maintains a table in each router, called the zone information table, that lists the relationships between zone
names and networks. In AppleTalk Phase 2, a single network number can be
associated with more than one zone name, or a single zone name can be
associated with more than one network. You can use .XPP driver routines to
obtain information from ZIP.
The AppleTalk Session Protocol (ASP) sets up and maintains sessions between a workstation and a server. A session consists of a logical (as opposed to physical) connection between two entities on the internet. ASP is a
nonsymmetrical protocol; that is, only one of the two entities involved in the
session (the workstation) can send commands. The other entity (the server) is
restricted to responding to the commands. ASP is used by the AppleTalk Filing
Protocol, for example, to allow a user to manipulate files on a file server. As
long as the session is open, the workstation can request directory information,
change file names, and so forth. The file server must respond to the
workstation's commands and cannot initiate any actions on its own.
between two entities on the internet. Either entity can write a stream of bytes
to the pipeline or read data bytes from the pipeline. ADSP is a symmetrical
protocol; that is, the two clients at either end of the connection are equal and
can perform exactly the same operations. ADSP is especially useful for
exchanging information between two equal entities, as in a telephone
communications network, or as required by a terminal emulation program for
sending or receiving a continuous stream of data. Because ADSP, like all other
high-level AppleTalk protocols, is a client of DDP, the data is actually sent as
data packets. This allows ADSP to correct transmission errors in a way that
would not be possible for a true data stream connection. Thus, ADSP retains
many of the advantages of a transaction-based protocol while providing to its
clients a full-duplex data stream.
The AppleTalk Filing Protocol (AFP) provides an interface between an application and a file server. AFP is a client of ASP and is used to access
AppleShare file servers on Macintosh computer workstations. When the user
opens a session with an AppleShare file server over an internet, the session
appears to any application running on the workstation that uses
File Manager routines as if the files on the file server were located on a AppleTalk Device Drivers, AppleTalk Connection Files & LAP Mgr
A protocol is only a set of rules, not a computer program. The various
AppleTalk protocols are implemented as Macintosh device drivers, including:
NBP, and AEP
• The .XPP driver, which implements ASP and the workstation
portions of ZIP and AFP
data link
A Macintosh computer on an AppleTalk network can also include one or more
AppleTalk connection files. An AppleTalk connection file has file type
'adev' and contains a link access protocol implementation for a data link (ELAP
user to select among AppleTalk connection files by using the Network control
panel to specify which network is to be used for the node's AppleTalk
connection.
Network control panel (Network 'cdev') file. When the user selects a
AppleTalk communications through the selected link access protocol and hence
through the selected hardware.
connection files implements one or more AppleTalk protocols.