1. AppleTalk and Networking
Matt Chinnock

2. Introduction
AppleTalk is a suite of protocols developed by Apple Inc for computer networking.
It was included in the original Macintosh in 1984
Now deprecated by Apple in favor of TCP/IP networking.

3. Design Appletalk followed the structure of the OSI model.
There are more protocols, some work together to achieve the same result as one OSI layer
Appletalk was not built around an Ethernet based medium
Protocols are interactive, with data moving up and down

4. Design

5. Design
One of the main features of AppleTalk was the introduction of two configuration protocols
AARP - AppleTalk Address Resolution Protocol
NBP - Name Binding Protocol

6. AARP and NBP
AARP - Allow AppleTalk hosts to automatically generate their own network addresses
NBP - Like a DNS, it maps network addresses to user-readable names
This allowed routers to provide all of this information, or "hardwire" the system to known addresses and names.

7. AARP
When powered on, an AppleTalk machine broadcasts an AARP probe packet asking for a network address, then waits to hear back from a controller, for example a router.
If another machine has that address, it will pick another address, and keep trying until it finds a free one

8. NBP
When a service started up on a machine, it registeres a name for itself on that machine, as chosen by the user
Names could include spaces, upper and lower case letters, and could be searched, making specific computers easy to find.

9. AARP and NBP Created a simple, easy to use set of network protocols
New machines were added to the network simply by plugging them in, and giving them a name if they needed one.
Once physically connected, an application called chooser automatically detects all peers
Named one of the most, if not the most simple way of connecting computers in a network

10. Problems with WAN’s
Although simple and easy to use, the naming service for each peer was creating a large amount of unwanted traffic when lots of new computers on whole networks were added.
Protocols that produces unwanted network traffic is considered “chatty”
The chattiness was significantly reduced with the release of Mac OS System 7

11. Addressing AppleTalk vs IP
An AppleTalk address is 24 bits long. It contains 16 bits, or less, in the network portion of the address and 8 bits, or less, in its host portion.
A TCP/IP address is 32 bits long. Network and host portions depend on the class of the network

12. Addressing
Each AppleTalk node’s address and network information is configured automatically by exchanging data from the client and server
All application-level protocols use dynamically-assigned socket numbers at both the client and server end as well

13. Implementation
Hardware implementation for AppleTalk was a high-speed serial protocol called LocalTalk
Used the Macintosh's built-in RS-422 ports, using a splitter box to allow up and downstreams.
Transfer speeds of up to kbit/s - fast at the time of release
RS-422 Cable

14. Implementation Uses a bus topology Cable type is twisted pair
Connection Box made by Apple

15. Compatability
Various versions of Unix Operating Systems had support for AppleTalk via a system called NetaTalk, which implemented the entire suite of AppleTalk protocols.
Most of these type are no longer used today

16. AppleTalk Today
Appletalk is still used today, only now it supports the TCP/IP protocol as to enable communication with the majority of other devices
Uses Ethernet technology
Can support fiber optics
Increased distance between nodes
Supports star topology

17. Summary
Phase 1 and 2 no longer implemented in Macs today in favour of TCP/IP protocol suite
One of the first automated network systems
Although not used so much now, was an important step to networking today

18. Questions
(excluding the Norwegians)