AppleTalk is a network operating system designed to connect Apple computers. Its components are built on Macintosh operating systems.

There are two main versions of AppleTalk depending on how many years in the past the network was implemented, Phase 1 and Phase 2. Phase 2 is the current installation as of about 2002. If anyone knows of something more current they should let me know. AppleTalk/Local Talk networks make use of CSMA/CA a media access control method.

STP cabling is usually used. But it is possible to use UTP or Fiber Optic cabling depending on cost and/or performance issues. The network topology is a bus or tree.

A Local Talk network is limited to 32 nodes. Local Talk is the data link layer protocol originally used for Macintoshes. Macintosh computers using Local Talk are linked together using their printer ports.

AppleShare is used as the file and print sharing protocol on AppleTalk networks

Rules of Engagement

AppleTalk networks make use of an addressing scheme in which each computer when it comes online:

• looks for a stored address that it used in a previous session

• if one isn't available then it chooses an address at random from those that are available

• then it broadcasts the address to make sure no other computer is using it

• if it is being used then it tries another

• if it isn't being used then it stores the address to potentially be used again when it returns online the next time.

AppleTalk was designed for small networks. Fortunately, these small networks can be connected together. Each subnetwork is called a zone and has a name for identification. Resources in other zones can be configured so that they can be accessed by a click on the zone name.

AppleTalk networks can be fairly directly connected to networks of other architectures such as Ethernet or Token Ring.

Apple has developed EtherTalk or TokenTalk, which are cards that enable Macintosh computers to connect to networks operating under 802.3 and 802.5 specifications, respectively.

Security

AppleTalk, like many network protocols, makes no provisions for network security. The design of the AppleTalk protocol architecture requires that security measures be implemented at higher application levels.

Cisco supports AppleTalk distribution lists, allowing control of routing updates on a per- interface basis. This security feature is similar to those that Cisco provides for other protocols.

Note that the Cisco implementation of AppleTalk does not forward packets with local source and destination network addresses. This behavior does not conform to the definition of AppleTalk in the Apple Computer inside AppleTalk publication.

However, this behavior is designed to prevent any possible corruption of the AARP table in any AppleTalk node that is performing address gleaning Through MAC.