networking prelim Flashcards
in 1819 proved that a wire carrying an electric current could
deflect a magnetized needle, opening the way for
wire-based telegraph networks. Today, computer
information network reach millions of people in
every part of the globe.
Hans Oersted
Three types of networks
Word-of-mouth communication
Telephone
Computer
Transmit information to person or group like word-ofmouth and Carry data, voice, and video communications
Computer networks
Communication cables and radio waves
* Specialized equipment to connect networks
telephone network communication infrastructure
Computer network components
– Computer hardware and software
– Print devices
– Network Devices
System components linked using various media
– Copper wire
– Fiber-optic cables
– Radio waves
– Infrared waves
– Microwaves
Three types of computer networks
– Local area networks (LANs)
– Metropolitan area networks (MANs)
– Wide area networks (WANs)
LAN
local area network
WAN
wide area network
MAN
metropolitan area network
Interconnects computers, printers, other equipment
– Consists of shared hardware and software resources
in close physical proximity
LAN
Spans a greater distance than a LAN
* Up to 48 kilometers (about 30 miles)
MAN
– Links multiple LANs within city or metropolitan region
* Typically uses fiber-optic/wireless connections
MAN
– Composed of two or more LANs or MANs
– Connected across distance greater than 48 km
– May have constituent LANs on different continents
WAN
Links different users across one or more organizations
– Provides variety of resources
– Used to fulfill business, research, educational tasks
– Typically consists of several LANs
– example: campus network
Enterprise network
what is node?
it is the station
Personal computer, server, mainframe, minicomputer, printer, fax, CD-ROM array, disk array
Wire cabling, fiber-optic cables, radio or infrared waves
– Provides transmission of signals to and from what?
Node
Nodes(the station)
Three network nodes important to users:
– Workstations
– Hosts
– Servers
Single computers offering multiuser access
– Repository for software applications and data files
– Host from two to as many as several thousand users
– Network operating system is key to capability
* Example: Microsoft Windows Server operating system
Server
Has CPU (central processing unit) and operating
system
– Home to local applications such as Microsoft Office
Runs network applications to access data on server or
mainframe
– May fulfill roles as client and host
Workstation computer
what is NIC ?
network interface card
Board installed in computer or network device
– Attached to communication media by connector or
antenna
NIC (network interface card)
Driving forces in networking technology
– Interpersonal communication
– Business transactions
– Entertainment products
physical layout combined with logical path
Topology
pattern of physical layout
– Wired networks: cabling laid in office, building, campus
– Wireless networks: types of antennas, devices,
direction of transmission
Cable plant
– Cable between each station on network
– Analogy: mountain climbers connected by a rope
Decentralized network layout
Each station physically connected to central device
– Analogy: star with workstation as its points
Centralized network layout
Main topologies
bus
ring
star
mesh
Hybrid topologies
star-bus
star-ring
– Consists of cables connecting PCs or file servers
– Visualizes connections as chain links
– Terminator attached to each end of bus cable segment
- Bus topology
IEEE
Institute of Electrical and Electronics Engineers
signals end of physical segment
– Functions as resistor that absorbs signal and critical on bus networks
– Prevents signal reflection back on to covered path
Terminator
continuous data path
– Workstations attached to cable at points around ring
* Transmitting data across ring topology
– Goes around ring to reach destination
– Continues until ends at source nod
Ring topology
multiple nodes attached to central
device (hub, switch, router)
– Cable segments radiate from center like a star
– Example: workstations connected to switch
Star topology
– Each radiating finger is separate logical bus segment
– Each segment terminated at both ends
Star-bus
Every node connected to every other node in network
– Provides network with fault tolerance
* Fault tolerance: built-in protection against failure
* If link breaks, nodes can still communicate
– Alternate communication paths increase as number of
nodes increase
Mesh topology
– Hub or access unit acts as linking device
– Transmission using logical communication of ring
– No need for built-in terminators
Star-ring
