chapter 5: computer networks. what is a network? *network: a connected system of objects or people...
TRANSCRIPT
What Is a Network?*Network: A connected system of objects or people*Computer network: A collection of computers and
other hardware devices connected together so that users can share hardware, software, and data, as well as electronically communicate with each other
*Internet: Largest computer network in the world*Examples of networks
-Business networks-Phone networks
Networking and Communications Applications
1 -Mobile phones (wireless phones)*Cellular (cell) phones
-Must be within range of cell tower to function
*Satellite phones -Used where cell service isn’t available
Networking and Communications Applications
Global positioning system (GPS): Uses satellites to determine the exact geographic location of the receiver
-Commonly found in cars today-Available as handheld units
-Used by the military, travelers, and others who need to know their precise location
Network Topologies
Topology: How the devices in the network (called nodes) are arranged
1-Star networks: All devices connect to a central device or hub)
2-Bus networks: All devices connect to a central cable3-Ring networks: Devices connect to one another in a
ring4-Mesh networks: Multiple connections between
devicesSome networks use a combination of topologies
Types of Networks
1-Local area network (LAN): Small geographical area (office, campus, etc.)
2-Wide area network (WAN): Large geographical area (Internet)
3-Intranet: Private network set up by an organization for use by its employees
4-Extranet: Intranet that is at least partially accessible to authorized outsiders
Data Transmission Characteristics
*Transmission directions-Simplex transmission (one way only)
-Half-duplex transmission (one way at a time)-Full-duplex transmission (both ways at the same
time)
Wireless Network Transmission Media
*Use radio signals -Short-range (such as Bluetooth)
wireless keyboard -Medium-range (such as Wi-Fi)
wireless LANs ,portable PC users to the Internet. -Longer-range (Wi-MAX)
wide geographic areas
Communications Protocols
*Communications protocol: An agreed-upon standard for transmitting data between two devices on a network
TCP/IP and Wireless Application Protocol (WAP)
*TCP/IP (Transmission Control Protocol/Internet Protocol): Used for transferring data over the Internet
-Uses packet switching
*Wireless Application Protocol (WAP):A standard for delivering Internet content to mobile devices
Networking Hardware for ConnectingDevices and Networks
*Hub: Central device that connects all of the devices on the network
*Gateway: A devices that connects two different networks
-Bridge: Usually connects wired LANs -Router : Can be wired or wireless
Other Networking Hardware
*Repeater: Amplifies signals along a network*Antenna: Used when Wi-Fi networks need to
go further than hardware normally allows