AppleTalk - network OS designed to connect Apple computers

AppleTalk is the network operating system specially designed to connect the Apple computers. The components of Apple Talk are built on Macintosh operating systems. The two main versions of AppleTalk are depends on how many years in the past the network was implemented, AppleTalk Phase 1 and AppleTalk Phase 2. Phase 2 is for installations in the year 2002.

CSMA/CA media access protocol is used by Apple Talk. Generally, STP cabling is used but it is possible to use UTP(Untwisted Pair Cable) or fiber optic cabling to. The network topology used in AppleTalk network is a tree or bus topology. Local Talk is the data link layer protocol initially used in the Macintosh Computers, it has a node limitation of 32 nodes. Macintosh computers using Local Talk can be linked or connected together with their printer ports. AppleShare is used for file and print sharing protocol on AppleTalk networks. Apple talk can be connected to the other network of some different architecture like Token ring or Ethernet. EtherTalk or TokenTalk developed by Apple can enable Macintosh computers to connect to networks operating under 802.3 and 802.5 specifications.

Advantages

1. Apple automatically includes the AppleTalk in the Macintosh operating system(OS).

2. It is Easy to implement and configure.

3. Setting up a small workgroup in AppleTalk is simple and inexpensive.

Disadvantages

1. It is not that suitable for very big networks.

2. It is little slow as compared with other LAN links.

3. It is unsuitable for bandwidth-intensive applications.

AppleTalk uses an address-resolution method much like TCP/IP's ARP(Address Resolution Protocol). The AppleTalk version is known as AARP. AARP uses broadcasts method to discover a hardware address (i.e. MAC address) of a node. The primary network layer routing protocol in AppleTalk is the Datagram Delivery Protocol (DDP). DDP provides a best-effort delivery which is ConnectionLess Datagram service like UDP. Five key implementations exist at the transport layer of the AppleTalk protocol suite:

1. Routing Table Maintenance Protocol (RTMP):
The Routing Table Maintenance Protocol (RTMP) is a transport layer protocol in the AppleTalk protocol suite that establishes and maintains routing tables in AppleTalk routers
2. Name Binding Protocol (NBP):
The Name Binding Protocol (NBP) is a transport layer protocol in the AppleTalk protocol suite that maps the addresses used at lower layers to AppleTalk names.
3. AppleTalk Update-Based Routing Protocol (AURP):
The AppleTalk Update-Based Routing Protocol (AURP) is a transport layer protocol in the AppleTalk protocol suite that allows two or more AppleTalk internetworks to be interconnected through a Transmission Control Protocol/Internet Protocol (TCP/IP) network to form an AppleTalk WAN. AURP encapsulates packets in User Datagram Protocol (UDP) headers, allowing them to be transported transparently through a TCP/IP network. An AURP implementation has two components: exterior routers and AURP tunnels.
4. AppleTalk Transaction Protocol (ATP):
The AppleTalk Transaction Protocol (ATP) is a transport layer protocol in the AppleTalk protocol suite that handles transactions between two AppleTalk sockets. A transaction consists of transaction requests and transaction responses, which are exchanged by the involved socket clients.
5. AppleTalk Echo Protocol (AEP):
The AppleTalk Echo Protocol (AEP) is a transport layer protocol in the AppleTalk protocol suite that generates packets that test the reachability of network nodes. AEP can be implemented in any AppleTalk node and has the statically assigned socket number 4 (the Echoer socket).