CAP 100 Chapter 8
Transfer rate
the speed with which modems transmit data measured in millions of bits (megabits) per second (Mbps) higher speed= faster send/ receive info
computer network term: NETWORK INTERFACE CARDS (NIC)
these are expansion cards located within the system unit that connect the computer to a network Sometimes referred to as a LAN adapter.
Wireless Connections- WiFi
(Wireless Fidelity) uses high-frequency radio signals to transmit data most home & business wireless networks use Wi-Fi.
Wireless Connections- WiMax
(Worldwide Interoperability for Microwave Access) extends the range of Wi-Fi networks using microwave connections. commonly used by universities and others to extend the capability of existing Wi-Fi networks.
Network Topologies: TREE NETWORK
(hierarchical) network a central node is connected to subordinate nodes forming a treelike structure. The central node is connected to two or more subordinate nodes that in turn are connected to other subordinate nodes, and so forth
Modem
(short for "modulator-demodulator") is a device that connects a user to the Internet. enables digital personal computers to communicate across different media (including telephone wires, cable lines, & radio waves) the speed in which they transmit data varies (higher speed = faster send/receive info) -(terms: transfer rate) 3 commonly used: -DSL -cable -wireless
Wireless Connections
-Do not use a solid substance to connect sending and receiving devices. -Rather, they move data through the air (radio waves).
Fourth-generation mobile telecommunications (4G)
-use LTE (Long Term Evolution) -connections to provide faster Internet access, allowing smartphones to easily stream videos and music.
Physical connections- COAXIAL CABLE
A high-frequency transmission cable, replaces the multiple wires of telephone lines with a single solid-copper core. In terms of the number of telephone connections, a coaxial cable has over 80 times the transmission capacity of twisted pair. Used to deliver television signals as well as to connect computers in a network.
The Wireless Revolution
A revolution that is expected to dramatically affect the way we communicate and use computer technology. Mobile devices like smartphones and tablets have brought dramatic changes in connectivity and communications. These wireless devices are becoming widely used for computer communication.
GPS (global positioning system)
A system that determines the precise position of something on Earth through a series of satellites, tracking stations, and receivers. One of the most interesting applications of satellite communications is for global positioning. A network of satellites owned and managed by the Department of Defense continuously sends location information to earth. -GPS devices use that information to uniquely determine the geographic location of the device.
wireless LAN (WLAN)
A wireless local area network uses radio frequencies to connect computers and other devices use a wireless access point (base station) as a hub. Hotspots provide Internet access in public places.
Types of Wireless Connections
Bluetooth Wi-Fi (Wireless Fidelity) Microwave WiMax (Worldwide Interoperability for Microwave Access) Cellular Satellite Infrared
Communication systems
Are electronic systems that transmit data from one location to another There are four basic elements: Sending and receiving devices Connection devices Data transmission specification Communication channel
Communication channel
Carry the data from one computer to another. There are two categories of communication channels: -physical connection -wireless.
T1, T3 (DS3), and OC (optical carrier) lines
Copper lines, T1 lines, that could be combined to form higher capacity options known as T3 or DS3 lines. Have been replaced by faster OC lines provide support for very-high-speed, all-digital transmission for large corporations.
Affordable Connection services- DSL
Digital Subscriber Line Service provided by telephone companies using existing lines to provide high-speed connections DSL is much faster than dial-up ADSL (Asymmetrical Digital Subscriber Line) is one of most widely used types of DSL
Applications that depend on communication system
E-mail- provides a fast, efficient alternative to traditional mail by sending and receiving electronic documents. Texting- provides very efficient direct text communication between individuals using short electronic messages. Videoconferencing- provides a very-low-cost alternative to long-distance telephone calls using electronic voice and video delivery. Electronic commerce- buying and selling goods electronically.
TCP/IP: IDENTIFICATION
Every computer on the Internet has a unique numeric address called an IP address (Internet protocol address). the Internet uses IP addresses to deliver e-mail and to locate websites. Because these numeric addresses are difficult for people to remember and use, a system was developed to automatically convert text-based addresses to numeric IP addresses= domain name server (DNS) (THIS converts text-based addresses to IP addresses)
Affordable Connection services- FiOS
Fiber-optic Service new technology & NOT widely available current providers of FiOS include Google & Verizon with speeds faster than cable or DSL
TCP/IP: PACKETIZATION
Info sent or transmitted across the Internet usually travels through numerous interconnected networks Before the message is sent, it is reformatted or broken down into small parts called packets. -Each packet is then sent separately over the Internet, possibly traveling different routes to one common destination. -At the receiving end, the packets are reassembled into the correct order.
home networks
LANs used by individuals in their homes and apartments allow different computers to share resources, including a common Internet connection. -Computers can be connected in a variety of ways, including electrical wiring, telephone wiring, special cables, and WIRELESS
local area networks (LANs)
Networks with nodes that are in close physical proximity—within the same building, for instance they span distances less than a mile and are owned and operated by individual organizations are widely used by colleges, universities, and other types of organizations to link personal computers and to share printers and other resources
Physical connections- TWISTED-PAIR CABLE
Pairs of copper wire twisted together. Standard telephone lines & Ethernet cables use them. Ethernet cables are often used in networks and to connect a variety of components to the system unit.
4 basic elements of communication systems
Sending and receiving devices- Are often a computer or specialized communication device. They originate (send) as well as accept (receive) messages in the form of data, information, and/or instructions. Connection devices- These devices act as an interface between the sending and receiving devices and the communication channel. They convert outgoing messages into packets that can travel across the communication channel. They also reverse the process for incoming messages. Data transmission specification- These are rules and procedures that coordinate the sending and receiving devices by precisely defining how the message will be sent across the communication channel. Communication channel- This is the actual connecting or transmission medium that carries the message. This medium can be a physical wire or cable, or it can be wireless.
Physical connections- FIBER-OPTIC CABLE
Transmits data as pulses of light through tiny tubes of glass. The data transmission speeds are incredible Compared to coaxial cable, it is lighter, faster, and more reliable at transmitting data. Replacing twisted-pair cable telephone lines.
Physical Connections
Use a solid medium to connect sending and receiving devices. These connections include: -twisted-pair, -coaxial, -fiber-optic cables.
computer network term: NETWORK ADMINISTRATOR
a computer specialist responsible for efficient network operations and implementation of new networks.
network gateway
a device that allows one LAN to be linked to other LANs or to larger networks example: the LAN of one office group may be connected to the LAN of another office group.
Digital signals
a discrete pulse, either on or off, that conveys information in a binary form represent the presence or absence of an electronic pulse *to convert digital signals to analog signals and vice versa you need a modem*
Uplink
a ground station that beams a signal to an orbiting communication satellite is a term relating to sending data to a satellite
Downlink
a ground station that receives a relayed signal from a communication satellite refers to receiving data from a satellite.
computer network term: ROUTER
a node that forwards or routes data packets from one network to their destination in another network.
computer network term: CLIENT
a node that requests and uses resources available from other nodes. example: a user's personal computer.
computer network term: SERVER
a node that shares resources with other nodes. Dedicated _________ specialize in performing specific tasks. Depending on the specific task, they may be called an application __________, communication _________, database __________, file _________, printer _________, or web __________
computer network term: DIRECTORY SERVER
a specialized server that manages resources, such as user accounts, for an entire network.
Bandwidth: VOICEBAND
aka low bandwidth used for standard telephone communication. Personal computers with telephone modems and dial-up service use ___________ band ___________ band is effective for transmitting text documents, but too slow for many types of transmission, including high-quality audio and video.
computer network term: HOST
any computer system connected to a network that provides access to its resources.
computer network term: NODE
any device that is connected to a network. examples: computer, printer, or data storage device.
Wide area networks (WANs)
are the largest type. They span states and countries or form worldwide networks. (typically span distances greater than 100 miles) The Internet is the largest wide area network in the world.
Connection devices
at first all computer communication used telephone lines because the telephone was o.g. designed for voice transmission telephones typically send & receive analog signals computers send & receive digital signals *to convert digital signals to analog signals and vice versa you need a modem*
Factors that affect how data is transmitted
bandwidth protocols
Client/server (hierarchical) network
central computers coordinate and supply services to other nodes; based on specialization of nodes; widely used on the Internet; able to handle very large networks efficiently; powerful network management software available.
computer network term: SWITCH
central node that coordinates the flow of data by sending messages directly between sender and receiver nodes. A hub previously filled this purpose by sending a received message to all connected nodes, rather than just the intended node.
wireless access point or base station
central place in a network where all communications pass thru this access point interprets incoming radio frequencies and routes communications to the appropriate devices
Analog signals
continuous waves that transmit information by altering the amplitude and frequency of the waves *to convert digital signals to analog signals and vice versa you need a modem*
computer network term: NETWORK OPERATING SYSTEMS (NOS)
control and coordinate the activities of all computers and other devices on a network. These activities include electronic communication and the sharing of information and resources.
Technology used for Network Security: FIREWALL
controls access (consists of hardware and software that control access to a company's intranet and other internal networks); Most use software or a special computer called a proxy server. (all communications pass through proxy server.)
Technology used for Network Security: Virtual private networks (VPN)
creates secure private connection between remote user and organization's internal network.
network architecture
describes how a network is arranged and how resources are coordinated and shared. encompasses a variety of different network specifics, including network topologies and strategies Network strategies define how information and resources are shared
network topology
describes the physical arrangement of the network. examples: -bus network -ring network -star network -tree network -mesh network
Network Topologies: STAR NETWORK
each device is connected directly to a central network switch. Whenever a node sends a message, it is routed to the switch, which then passes the message along to the intended recipient. most common type today
Network Topologies: BUS NETWORK
each device is connected to a common cable called a bus or backbone, and all communications travel along this bus.
Network Topologies: RING NETWORK
each device is connected to two other devices, forming a ring. When a message is sent, it is passed around the ring until it reaches the intended destination.
https
hypertext transfer protocol secure is widely used to protect the transfer of sensitive information.
Affordable Connection services- CELLULAR SERVICE PROVIDERS
including Verizon, AT&T, Sprint, and T-Mobile, support voice and data transmission to wireless devices using cellular networks. These networks have gone through different generations - 1G, 2G, 3G, 4G, 5G
Computer network
is a communication system that connects two or more computers so that they can exchange information and share resources. -Networks can be set up in different arrangements to suit users' needs.
Connectivity
is a concept related to using computer networks to link people and resources. you can link or connect to large computers and the Internet, providing access to extensive information resources.
Bandwidth
is a measurement of the width or capacity of the communication channel. it means how much info can move across the communication channel in a given amount of time. There are four categories of this -voiceband -medium band -broadband -baseband example: -to transmit text documents, a slow bandwidth would be acceptable. -to effectively transmit video and audio, a wider bandwidth is required.
personal area network (PAN)
is a type of wireless network that works within a very small area—your immediate surroundings. connect cell phones to headsets, keyboards to cell phones, and so on. are wireless networks for PDAs, cell phones, and other wireless devices. most popular: bluetooth
fifth-generation mobile telecommunications (5G)
is being developed, with speeds that rival home Internet connections and is expected to be widely available by 2020.
Computer communications
is the process of sharing data, programs, and information between two or more computers.
Bandwidth: MEDIUM BAND
is used in special leased lines to connect midrange computers and mainframes, as well as to transmit data over long distances ____________ band is capable of very-high-speed data transfer.
Bandwidth: BROADBAND
is widely used for DSL, cable, and satellite connections to the Internet Several users can simultaneously use a single ___________ band connection for high-speed data transfer
Bandwidth: BASEBAND
is widely used to connect individual computers that are located close to one another. _________ band is able to support high-speed transmission (like broadband) _________ band can only carry a single signal at a time (unlike broadband)
Internet Technologies: EXTRANET
like intranet except connects more than one organization; typically allows suppliers and others limited access to their networks.
Metropolitan area networks (MANs)
link office buildings within a city, spanning up to 100 miles. unlike a LAN a ______ is not typically owned by a single org. but by a group of org. or by a single network service provider that provides services for free
Network Topologies: MESH NETWORK
newest; each node has two or more connecting nodes.
Peer-to-peer network (P2P)
nodes have equal authority and act as both clients and servers; widely used to share games, movies, and music over the Internet; easy to set up and use; lacks security controls.
Types of Modems- WIRELESS MODEMS
or WWAN= wireless wide area network almost all computers today have built in WWAN -for those who don't, wireless adapter cards are available that plug into USB or special card ports
hotspots
or access points that provide Internet access are widely available in public places such as coffee shops, libraries, bookstores, colleges, and universities typically use Wi-Fi technology Many of these services are free and easy to find using free locator site Most mobile computing devices have an internal wireless network card to connect to ______________
Internet Technologies: INTRANET
private network within an organization; uses browsers, websites, and web pages. Typical applications include electronic telephone directories, e-mail addresses, employee benefit information, internal job openings, and much more.
Affordable Connection services- CABLE SERVICE
provided by cable TV companies using their existing TV cables usually faster than DSL
Protocols
rules for exchanging data between computers (For data transmission to be successful, sending and receiving devices must follow a set of communication rules for the exchange of information)
Ethernet LAN
several computer connect together through a hub or switch most common standard in which nodes can be connected to one another and ways in which their communications are controlled in a LAN
Wireless Connections- BLUETOOTH
short-range radio communication standard that transmits data over short distances of up to approximately 33 feet. used for: wireless headsets, printer connections, and handheld devices.
First-generation mobile telecommunications (1G)
started in the 1980s using analog radio signals to provide analog voice transmission service
Second-generation mobile telecommunications (2G)
started in the 1990s using digital radio signals
Third-generation mobile telecommunications (3G)
started in the 2000s and provided services capable of effective connectivity to the Internet, marking the beginning of smartphones.
Demodulation
the process of converting from analog to digital
Modulation
the process of converting from digital to analog
TCP/IP
transmission control protocol/Internet protocol The essential features of this protocol: -identifying sending and receiving devices -breaking information into small parts, or packets, for transmission across the Internet.
Affordable Connection services- SATELLITE CONNECTION SERVICES
use satellites to provide wireless connections slower than DSL and cable modem connections are available almost anywhere using a satellite-receiving disk
Wireless Connections- MICROWAVE
uses high-frequency radio waves. line-of-sight communication uses light waves over a short distance (bc they can only travel in a straight line) used to send data between buildings (bc they cannot bend w the curvature of the earth) longer distances require microwave stations (w dishes or antennas)
Wireless Connections- INFRARED
uses infrared light waves over a short distance line-of-sight communication (bc they can only travel in a straight line) example: TV remote control
Wireless Connections- SATELLITE
uses microwave relay stations orbit at a precise point & speed above the earth (terms uplink & downlink) major drawback to satellite communication is that bad weather can sometimes interrupt the flow of data. GPS (global positioning system) tracks geographic locations.
Wireless Connections- CELLULAR
uses multiple antennae (or cell towers) to send and receive data within relatively small geographic regions (or cells)
Types of Modems- DSL (digital subscriber line)
uses standard phone lines to create a high-speed connection directly to your phone company's offices these devices are usually external & connect to the system unit using either USB or an Ethernet port
Types of Modems- CABLE MODEM
uses the same coaxial cable as the TV creates high-speed connections using the systems unit's USB or Ethernet port
Dial-up service
using existing telephones and telephone modems to connect to the Internet.
Strategy (for networks)
way of sharing information and resources. examples: client/server and peer-to-peer
Technology used for Network Security: Intrusion detection systems (IDS)
work with firewalls to protect an organization's network; use sophisticated statistical techniques to recognize and disable network attacks