Technical data

Glossary 8
Agilent Connectivity Guide 205
There are many different types of LANs, Ethernets being the most
common for PCs. Most Apple Macintosh networks are based on
Apple's AppleTalk network system, which is built into Macintosh
computers. The following characteristics differentiate one LAN from
another:
topology: The geometric arrangement of devices on the network. For
example, devices can be arranged in a ring or in a straight line.
protocols: The rules and encoding specifications for sending data.
The protocols also determine whether the network uses a
peer-to-peer or client/server architecture.
media: Devices can be connected by twisted-pair wire, coaxial
cables, or fiber optic cables. Some networks do without connecting
media altogether, communicating instead via radio waves.
LANs are capable of transmitting data at very fast rates, much faster
than data can be transmitted over a telephone line. However, the
distances are limited and there is also a limit on the number of
computers that can be attached to a single LAN.
Listener
A device that can receive data from the bus when instructed
(addressed to listen) by the System Controller.
lock
A state that prohibits other users from accessing a resource, such as a
device or interface.
logical unit
A number associated with an interface. A logical unit, in SICL and
Agilent VEE, uniquely identifies an interface. Each interface on the
controller must have a unique logical unit.
network
A group of two or more computer systems linked together. There are
many types of computer networks, including: