AppleTalk Remote Access
Encyclopedia
AppleTalk Remote Access, or ATRA, was a protocol stack
that allowed AppleTalk
to be run over modem
s. It became a fairly major product for Apple Computer
in the early to mid-1990s when their first portable and laptop computers were available (and very popular). ARA slowly disappeared in the late 1990s when TCP/IP took over the vast majority of networking needs, notably remote access.
Most networking protocols have strong "layering" that separates the various jobs inside the protocol to different pieces of software. This allows them to be run on top of any hardware by replacing the lowest level software, the hardware drivers. For instance, IP can be made to run on a variety of Ethernet
cards or even TokenRing
with little effort. For slower speeds, like on modems, things become somewhat more difficult, as the protocols often have "invisible" assumptions about timing and performance that make it inefficient with very limited bandwidth.
AppleTalk included a number of features that made this even more difficult. In particular AppleTalk had a number of internal tasks for discovery and naming that ran all the time and made the protocol "chatty". This added to the bandwidth problems, making it even less efficient in this case.
Thus ARA was considerably more complex than similar solutions for IP, replacing many parts of the AppleTalk stack and seriously modifying others. As a result ARA was quite large, larger than the basic AppleTalk stack, and somewhat memory hungry. It was also slow, a problem it shared with IP at similar speeds.
Nevertheless, ARA was the only protocol available, and also shared the typical Apple properties of being easy to install, set up and run. It became a fairly profitable product on its own, and was sold widely in stores. However the introduction of SLIP
and the increased use of IP on the Macintosh led to some infighting within Apple as the profits from ARA were reduced. This led Apple to place their IP remote access software in ARA as well, although this had the side effect of making various freeware implementations much more popular. As support for TCP/IP was added, the product line became known as Apple Remote Access. Later versions supported AppleTalk connections over ARAP and TCP/IP connections over PPP.
ARA remained an important, if somewhat less so, product for Apple into the late 1990s. In Mac OS X
it is no longer required, as Apple has migrated the vast majority of their networking software to IP, and includes remote access software for free.
Protocol stack
The protocol stack is an implementation of a computer networking protocol suite. The terms are often used interchangeably. Strictly speaking, the suite is the definition of the protocols, and the stack is the software implementation of them....
that allowed AppleTalk
AppleTalk
AppleTalk is a proprietary suite of protocols developed by Apple Inc. for networking computers. It was included in the original Macintosh released in 1984, but is now unsupported as of the release of Mac OS X v10.6 in 2009 in favor of TCP/IP networking...
to be run over modem
Modem
A modem is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data...
s. It became a fairly major product for Apple Computer
Apple Computer
Apple Inc. is an American multinational corporation that designs and markets consumer electronics, computer software, and personal computers. The company's best-known hardware products include the Macintosh line of computers, the iPod, the iPhone and the iPad...
in the early to mid-1990s when their first portable and laptop computers were available (and very popular). ARA slowly disappeared in the late 1990s when TCP/IP took over the vast majority of networking needs, notably remote access.
Most networking protocols have strong "layering" that separates the various jobs inside the protocol to different pieces of software. This allows them to be run on top of any hardware by replacing the lowest level software, the hardware drivers. For instance, IP can be made to run on a variety of Ethernet
Ethernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
cards or even TokenRing
IBM token ring
thumb|Two examples of token ring networks: a) Using a single [[Media Access Unit|MAU]] b) Using several MAUs connected to each otherthumb|Token ring networkthumb|IBM hermaphroditic connector with locking clipthumb|An IBM 8228 MAU...
with little effort. For slower speeds, like on modems, things become somewhat more difficult, as the protocols often have "invisible" assumptions about timing and performance that make it inefficient with very limited bandwidth.
AppleTalk included a number of features that made this even more difficult. In particular AppleTalk had a number of internal tasks for discovery and naming that ran all the time and made the protocol "chatty". This added to the bandwidth problems, making it even less efficient in this case.
Thus ARA was considerably more complex than similar solutions for IP, replacing many parts of the AppleTalk stack and seriously modifying others. As a result ARA was quite large, larger than the basic AppleTalk stack, and somewhat memory hungry. It was also slow, a problem it shared with IP at similar speeds.
Nevertheless, ARA was the only protocol available, and also shared the typical Apple properties of being easy to install, set up and run. It became a fairly profitable product on its own, and was sold widely in stores. However the introduction of SLIP
Slip
- In science and technology :* Slip , an aqueous suspension of minerals, and frequently deflocculant.* Slip , a positional displacement in a sequence of transmitted symbols...
and the increased use of IP on the Macintosh led to some infighting within Apple as the profits from ARA were reduced. This led Apple to place their IP remote access software in ARA as well, although this had the side effect of making various freeware implementations much more popular. As support for TCP/IP was added, the product line became known as Apple Remote Access. Later versions supported AppleTalk connections over ARAP and TCP/IP connections over PPP.
ARA remained an important, if somewhat less so, product for Apple into the late 1990s. In Mac OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...
it is no longer required, as Apple has migrated the vast majority of their networking software to IP, and includes remote access software for free.