AppleTalk Protocols

AppleTalk is the architecture used on with Apple brand computers and is a suite of protocols for networking Apple computers. Some of the protocols are:

• AppleShare - Works at the application layer to provide services.
• AFP - AppleTalk Filing protocol - Makes network files appear local by managing file sharing at the presentation layer.
• ATP - AppleTalk Transaction Protocol provides a Transport Layer connection between computers. Three transaction layers:
  • transaction requires (TREQ)
  • transaction response (TRESP)
  • transaction release (TREL)
• DDP - Datagram Delivery Protocol is a routable protocol that provides for data packet transportation. It operates at the network layer at the same level of the IP protocol.

The AppleTalk networking scheme puts computers into groups called zones. This is similar to workgroups on a Windows network.

Four Session layer protocols

• ASP - AppleTalk session protocol controls the starting and ending of sessions between computers called nodes. It works at the session level. The NBP, described below is used to get addresses from computer names. ATP is used at the transport level.
• ADSP - AppleTalk data stream protocol manages the flow of data between two established socket connections.
• ZIP - Zone information protocol used with RTMP to map zones. Routers use zone information tables (ZITs) to define network addresses and zone names.
• PAP - Printer access protocol manages information between workstations and printers.

Other Protocols

• NBP - Name-binding protocol translates addresses into names.
• AEP - AppleTalk echo protocol uses echoes to tell if a computer, or node, is available.
• RTMP - Routing table maintenance protocol is used to update routers with information about network status and address tables. The whole address table is sent across the network.
• ARUP - AppleTalk update routing is a newer version of RTMP. 

http://www.comptechdoc.org/independent/networking/guide/nettappletalk.html