AppleTalk

 

Introduction.  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/LocalTalk 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 LocalTalk network is limited to 32 nodes.  LocalTalk is the data link layer protocol originally used for Macintoshes.  Macintosh computers using LocalTalk 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.

Some of the major advantages of AppleTalk are

  • Apple automatically includes AppleTalk in the Macintosh operating system.
  • Easy to implement and configure
  • Setting up a small workgroup is simple and inexpensive

Some of the major disadvantages are

  • It is not suitable for very large networks
  • It is very slow compared to other LAN links at 230.4 Kbps
  • It is unsuitable for bandwidth intensive applications