OSI Model Corresponding AppleTalk layersApplication Apple Filing Protocol (AFP)

Presentation Apple Filing Protocol (AFP)

Session Zone Information Protocol (ZIP)AppleTalk Session Protocol (ASP)

Transport AppleTalk Transaction Protocol (ATP)AppleTalk Echo Protocol (AEP)

Network Datagram Delivery Protocol (DDP)

Data link EtherTalk Link Access Protocol (ELAP)LocalTalk Link Access Protocol (LLAP)

Physical LocalTalk driverEthernet driver

Token Ring driverFDDI driver

Application & presentation

AFP: (apple filing protocol).

The AppleTalk Filing Protocol (AFP) is the file sharing

protocol of the AppleTalk architecture. It provides a

native mode interface to Apple file system resources.

Apple files are comprised of two data structures called

forks. An Apple file may be accessed by its data fork or

its resource fork. The data fork holds raw file data

while the resource fork contains information used by the

operating system to manage icons and drivers.

ASP

The AppleTalk Session Protocol (ASP) manages sessions for higher layer

protocols such as AFP. ASP issues a unique session identifier for each

logical connection and continuously monitors the status of each

connection. It maintains idle sessions by periodically exchanging keep

alive frames in order to verify the session status.

Zone Information Protocol

ZIP was the protocol by which AppleTalk network numbers were

associated with zone names. A zone was a subdivision of the

network that made sense to humans (for example, "Accounting

Department"); but while a network number had to be assigned to a

topologically-contiguous section of the network, a zone could include

several different discontiguous portions of the network.

AppleTalk Transaction Protocol

ATP was the original reliable transport-level protocol for AppleTalk, built

on top of DDP. At the time it was being developed, a full, reliable

connection-oriented protocol like TCP was considered to be too

expensive to implement for most of the intended uses of AppleTalk. Thus,

ATP was a simple request/response exchange, with no need to set up or

tear down connections.

AppleTalk Echo Protocol

AEP (AppleTalk Echo Protocol) is a transport layer protocol designed to

test the reachability of network nodes. AEP generates packets to be

sent to the network node and is identified in the Type field of a packet

as an AEP packet.

Datagram Delivery Protocol :

DDP was the lowest-level data-link-independent

transport protocol.

EtherTalk Link Access Protocol (ELAP)

EtherTalk was developed by Apple as an extension of the

Ethernet data link. The extension allows the use of an

Ethernet data link and cabling in the AppleTalk network.

LocalTalk Link Access Protocol (LLAP)This protocol manages the node-to-node

transmission of data packets in the network. LLAP

governs

access to the link and provides a means for nodes to

discover valid addresses. It does not guarantee packet

delivery; it does guarantee that those packets that are

delivered are error-free.

Fiber Distributed Data

Interface (FDDI)

is a standard for data transmission in a local area network

LocalTalk

is a particular

implementation of

the physical layer of

the AppleTalk networking sy

stem from Apple Computer.

LocalTalk specifies a

system of shielded twisted

pair cabling, plugged into

self-

terminating transceivers,

running at a rate of 230.4

kbit/s. CSMA/CA was

implemented as a random multiple access method.

MOSHMI

ADITYA

AKASH YOGESH