All devices are connected to a central cable, called the bus
Can be a computer or some other device, such as printer. Every node has a unique network address, sometimes called a Data Link Control (DLC) address or Media Access Control (MAC).
All devices are connected to one another in the shape of a closedloop, so that each device is connected directly to two other devices, one on
either side of it.
All devices are connected to a central hub. Nodes communicate
across the network by passing data through the hub.
Groups of star-configured networks are connected to a linear bus
The measure of how much information can flow from one place to another in a given amount of time
Campus-Area Networks (CANs)
computers are within a limited geographic area, such as a campus or military base
An application that runs on a large and powerful
centralized computer called a mainframe computer. Users access the mainframe computer through a terminal
Home-Area Networks (HANs)
network contained within a user's home that connects a person's digital devices
Local-Area Networks (LANs)
Computers are geographically close together
(that is, in the same building)
Metropolitan-Area Networks (MANs)
A data network designed for a town or
The protocol defines a common set of rules and signals that a computer on the network uses to communicate. One of the most popular protocols for LANs is called Ethernet. Another popular LAN protocol for PCs is the IBM token-ring network
Computers and devices that allocate resources for a network.
Wide-Area Networks (WANs)
The computers are farther apart and are
connected by telephone lines or radio wavers
A device that allows you to segment a large
network into two smaller, more efficient networks. It
monitors the information on both sides of the
network so that it can pass packets of information to
the correct location
A hardware device that connects the nodes in
the arms of a star network. A hub can be active—boosts the signals, or it can be passive—simply relay the signal.
A computer-to-computer communication
device that converts digital signals from the
computer to analog signals for the telephone lines.
Network Interface Card (NIC)
A hardware component that enables both client computers and servers to communicate with one another. Also known as a network adapter card.
Device used to connect two cables and
that boosts the signal before sending it along.
A network device used to connect networks
of different types and forwards packets from one
network to another, even those separated by great
distances. A router determines the best route to use
to deliver the data
A multi-port bridge that allows several segments of a network to communicate with one another.
Provides services directly to user appllications. Provides privacy mechanisms, authencating the intended communication partners, and determining if adequate resources are present
performs data transformations to provide a common interface for user applications, including services such as reformatting, data compression, and encryption.
session(OSI level 5)
Establishes, manages, and ends user connections and manages interaction between end systems
transport (OSI level 4)
Provides error recovery and flow control between the two end points of the network connection
Network (OSI level 3)
Establishes, maintains and terminates network connections.
Data-Link (OSI level2)
Defines how data frames are recognized and provde necessary flow control and error handling.
Physical (OSI leve 1)
Standards for this layer define such parameters as the amoung of signal voltage, duration of voltages (bits)
When the computer is booted, the virus executes.
File infector viruses
The virus attaches itself to a file or program and activates at any time.
A barrier, such as a router, bridge, or gateway, that sits between the network and the
outside world. It is designed to keep unacceptable packets from reaching the internal network.
Backs up all files and flags all files as backed up.
A simple text file that records information about the device, system, or application
process of examining and verifying information. Network audits can return information about the hardware and software on the network.
Uninterruptible Power Supply (UPS)
A large rechargeable battery that provides power to connected devices for a period of time if main electrical power goes out.
Bits of computer programming, or code, that hide in computer programs or on the boot sector of storage devices.