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Requirements for Communication (Computer)
Senders and Receivers There must a be a sender and a receiver with something to share via a message to facilitate communication
Senders and Receivers There must a be a sender and a receiver with something to share via a message to facilitate communication
Communication Medium A medium must exist between the sender and receiver over which the message travels (e.g., a cable)
Communication Medium A medium must exist between the sender and receiver over which the message travels (e.g., a cable)
ProtocolsProcedures, rules, or standards must be followed by computers when sending or receiving data
ProtocolsProcedures, rules, or standards must be followed by computers when sending or receiving data
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Computer Networks
Centralized Computing (1970s)The centralized computing model utilizes a central computer (mainframe) connected to terminals with all processing being done on the central computer
Centralized Computing (1970s)The centralized computing model utilizes a central computer (mainframe) connected to terminals with all processing being done on the central computer
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Computer Networks
Distributed Computing (1980s)The use of small computers networked together allowing users to perform a subset of tasks that in aggregate are equal to that of a centralized computer while also being able to share information between those computers
Distributed Computing (1980s)The use of small computers networked together allowing users to perform a subset of tasks that in aggregate are equal to that of a centralized computer while also being able to share information between those computers
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Computer Networks
Collaborative Computing (1990s)A synergistic form of distributed computing in which two or more networked computers are used to accomplish a common processing task where they are not only sharing data but also sharing processing responsibilities
Collaborative Computing (1990s)A synergistic form of distributed computing in which two or more networked computers are used to accomplish a common processing task where they are not only sharing data but also sharing processing responsibilities
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Types of Networks
NetworksMost networks utilize a combination of computing models that have evolved over time and are connected by one or more of the following network types:
• Local Area Network (LAN)• Wide Area Network (WAN)• Global Networks• Enterprise Network• Value-added Network (VAN)• Metropolitan Network (MAN)• Personal Area Network (PAN)
NetworksMost networks utilize a combination of computing models that have evolved over time and are connected by one or more of the following network types:
• Local Area Network (LAN)• Wide Area Network (WAN)• Global Networks• Enterprise Network• Value-added Network (VAN)• Metropolitan Network (MAN)• Personal Area Network (PAN)
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Network Types – Local Area Network
Local Area NetworkA computer network that spans a relatively small area allowing all computer users to connect with each other to share information and peripheral devices (e.g., printers)
Local Area NetworkA computer network that spans a relatively small area allowing all computer users to connect with each other to share information and peripheral devices (e.g., printers)
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Types of Networks – Wide Area Networks (WAN)
Wide Area Networks (WANs)A computer network that spans a relatively large area and is typically used to connect two or more LANs using different kinds of hardware and transmission media to cover large distances efficiently
Wide Area Networks (WANs)A computer network that spans a relatively large area and is typically used to connect two or more LANs using different kinds of hardware and transmission media to cover large distances efficiently
GlobalA WAN that spans multiple countries and may include the networks of several organizations (e.g. the Internet)
GlobalA WAN that spans multiple countries and may include the networks of several organizations (e.g. the Internet)
Value-added Network (VAN)A medium-speed, third-party-managed network that is economical as it is shared by multiple customer organizations that lease lines rather than investing in dedicated network equipment
Value-added Network (VAN)A medium-speed, third-party-managed network that is economical as it is shared by multiple customer organizations that lease lines rather than investing in dedicated network equipment
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Types of Networks – Wide Area Networks (WAN)
Enterprise Network & MAN
EnterpriseA WAN that is the result of connecting the disparate networks of a single organization
EnterpriseA WAN that is the result of connecting the disparate networks of a single organization
Metropolitan Area (MAN) A WAN network of limited geographic scope, typically in a city-wide area that combines both LAN and high-speed fiber-optic technologies
Metropolitan Area (MAN) A WAN network of limited geographic scope, typically in a city-wide area that combines both LAN and high-speed fiber-optic technologies
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Types of Networks – Personal Area Network (PAN)
Personal Area NetworkAn emerging technology that uses wireless communication to exchange data between commuting devices using short-range radio communication (Bluetooth), typically within an area of ten meters
BluetoothIs the enabling technology of the Personal Area Network and is a specification for personal networking of desktop computers, mobile phones, pagers, portable stereos, and other handheld devices developed by its founders Ericsson, IBM, Intel, Nokia, and Toshiba
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Networking Fundamentals – Servers and Clients
ServerAny computer on a network that makes access to files, printing, communication, and other services available to users on the network
ServerAny computer on a network that makes access to files, printing, communication, and other services available to users on the network
ClientAny computer, such as a user’s workstation or a PC on the network, or software application such as word processing program that uses services provided by the server. A client only requests service and usually has only one user
ClientAny computer, such as a user’s workstation or a PC on the network, or software application such as word processing program that uses services provided by the server. A client only requests service and usually has only one user
NetworkA network consists of three separate components: servers, clients and peers
NetworkA network consists of three separate components: servers, clients and peers
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Networking Fundamentals – Peers
PeerA computer that may both request and provide services PeerA computer that may both request and provide services
Peer-to-Peer Networks (P2P)Enables any computer or device on the network to provide or request services with all peers having equivalent capabilities and responsibilities (e.g., Napster)
Peer-to-Peer Networks (P2P)Enables any computer or device on the network to provide or request services with all peers having equivalent capabilities and responsibilities (e.g., Napster)
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Networking Fundamentals - Network Services
Network ServicesThe capabilities that networked computers share through the multiple combinations of hardware and software
Network ServicesThe capabilities that networked computers share through the multiple combinations of hardware and software
File Services (a)The networked computers store, retrieve, and move data files in an efficient manner.
File Services (a)The networked computers store, retrieve, and move data files in an efficient manner.
Print Services (b)The capabilities used to control and manage user’s access to network printers, plotters, fax equipment, etc.
Print Services (b)The capabilities used to control and manage user’s access to network printers, plotters, fax equipment, etc.
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Networking Fundamentals - Network Services
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Networking Fundamentals - Network Services
Network Operating System (NOS)Is software that controls the network enabling computers to communicate by enabling network services
Network Operating System (NOS)Is software that controls the network enabling computers to communicate by enabling network services
Message Services (c)The capabilities that include storing, accessing, and delivering of text, binary, graphic, digitized video and audio data
Message Services (c)The capabilities that include storing, accessing, and delivering of text, binary, graphic, digitized video and audio data
Application Services (d)The capabilities that run software for network clients and enable computers to share processing power
Application Services (d)The capabilities that run software for network clients and enable computers to share processing power
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Networking Fundamentals - Network Services
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Networking Fundamentals – Transmission Media
Transmission MediaThe physical pathway to send data and information between two or more entities on the network. Characteristics of the media include the following:
Transmission MediaThe physical pathway to send data and information between two or more entities on the network. Characteristics of the media include the following:
BandwidthIs the transmission capacity of a communications channel or computer, measured in megabits per second (Mbps) (amount of binary data transmitted per second)
BandwidthIs the transmission capacity of a communications channel or computer, measured in megabits per second (Mbps) (amount of binary data transmitted per second)
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Networking Fundamentals – Transmission Media
AttenuationThis results when the power of an electrical signal weakens as it is sent over increasing distance
AttenuationThis results when the power of an electrical signal weakens as it is sent over increasing distance
Electro Magnetic Interference (EMI)Interference commonly caused by fluorescent lights, weather, or other electronic signals that affects the distance a signal can travel (increased attenuation)
Electro Magnetic Interference (EMI)Interference commonly caused by fluorescent lights, weather, or other electronic signals that affects the distance a signal can travel (increased attenuation)
EavesdroppingThe undetected capturing of network informationEavesdroppingThe undetected capturing of network information
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Networking Fundamentals – Media (Cable)
Twisted PairTwo or more pairs of insulated copper wires twisted together and may be shielded (STP) or unshielded (UTP). It is the lowest capacity of the cable options
Twisted PairTwo or more pairs of insulated copper wires twisted together and may be shielded (STP) or unshielded (UTP). It is the lowest capacity of the cable options
CoaxialContains a solid inner copper conductor surrounded by insulation and outer braided copper or foil shield. It comes in UTP and STP and is higher capacity than twisted pair
CoaxialContains a solid inner copper conductor surrounded by insulation and outer braided copper or foil shield. It comes in UTP and STP and is higher capacity than twisted pair
Fiber-OpticMade of light-conducting glass or plastic core, surrounded by more glass, called cladding, and a tough outer sheath. It is high capacity and used in high speed backbones
Fiber-OpticMade of light-conducting glass or plastic core, surrounded by more glass, called cladding, and a tough outer sheath. It is high capacity and used in high speed backbones
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Networking Fundamentals – Media (Cable)
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Networking Fundamentals – Media (Wireless)
WirelessA communication mechanism that has no physical transmission media, hence the name wireless, that works by transmitting electromagnetic signals through the air. Types of wireless media include:
• Infrared line of sight • High-frequency radio• Microwave methods
WirelessA communication mechanism that has no physical transmission media, hence the name wireless, that works by transmitting electromagnetic signals through the air. Types of wireless media include:
• Infrared line of sight • High-frequency radio• Microwave methods
Infrared Line of SightUses high-frequency light waves to transmit data on an unobstructed path between nodes – computers or some other device such as a printer – on a network up to 24.4 meters (i.e. most electronics remotes use this infrared light) and are susceptible to attenuation, EMI, eavesdropping, high-intensity light, and smoke
Infrared Line of SightUses high-frequency light waves to transmit data on an unobstructed path between nodes – computers or some other device such as a printer – on a network up to 24.4 meters (i.e. most electronics remotes use this infrared light) and are susceptible to attenuation, EMI, eavesdropping, high-intensity light, and smoke
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Networking Fundamentals – Media (Wireless)
High-Frequency RadioA fast transmission medium for distances up to 40 kilometers, depending on obstructions. Attenuation is very low but is susceptible to EMI and eavesdropping. Applications of this technology include pagers, cellular phones, and Wi-Fi
High-Frequency RadioA fast transmission medium for distances up to 40 kilometers, depending on obstructions. Attenuation is very low but is susceptible to EMI and eavesdropping. Applications of this technology include pagers, cellular phones, and Wi-Fi
PagersA one way, wireless messaging system in multiple typesPagersA one way, wireless messaging system in multiple types
Cellular PhoneA two-way wireless communication that assigns unique frequencies to calls and can transmit in analog or digital
Cellular PhoneA two-way wireless communication that assigns unique frequencies to calls and can transmit in analog or digital
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Networking Fundamentals – Media (Wireless)
Wireless LANs or Wireless Fidelity (Wi-Fi)Based on a standard called 802.11, this technology enables multiple computers to share Internet access, files, and peripheral devices
Wireless LANs or Wireless Fidelity (Wi-Fi)Based on a standard called 802.11, this technology enables multiple computers to share Internet access, files, and peripheral devices
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Networking Fundamentals – Media (Microwave)
MicrowaveA high frequency radio signal that is sent through the air using either terrestrial (earth-based) or satellite systems
MicrowaveA high frequency radio signal that is sent through the air using either terrestrial (earth-based) or satellite systems
Terrestrial MicrowaveA line-of-site technology (unobstructed) used to cross inaccessible terrain or to connect buildings where cable installation would be expensive. Attenuation is low over short distance but higher over longer distances, and high winds, heavy rain, EMI and eavesdropping are also problems
Terrestrial MicrowaveA line-of-site technology (unobstructed) used to cross inaccessible terrain or to connect buildings where cable installation would be expensive. Attenuation is low over short distance but higher over longer distances, and high winds, heavy rain, EMI and eavesdropping are also problems
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Networking Fundamentals – Media (Microwave)
Satellite MicrowaveA line-of-site technology that uses relay stations to transfer signals between antennae located on earth and a satellite orbiting the earth. It can be used to access the very remote locations and like a terrestrial microwave, attenuation, EMI and eavesdropping are also problems
Satellite MicrowaveA line-of-site technology that uses relay stations to transfer signals between antennae located on earth and a satellite orbiting the earth. It can be used to access the very remote locations and like a terrestrial microwave, attenuation, EMI and eavesdropping are also problems
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Networking Fundamentals – Media (Wireless)
Wireless Media Benefits and Drawbacks
Comparisons of Wireless Media
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Network Hardware and Software (Network Topologies)
Network TopologiesRefers to the shape of a network and comes in three types:
Network TopologiesRefers to the shape of a network and comes in three types:
Star NetworkThe network is configured in the shape of a star with all nodes or workstations connected to a central hub, or concentrator, through which all messages pass
Star NetworkThe network is configured in the shape of a star with all nodes or workstations connected to a central hub, or concentrator, through which all messages pass
Ring NetworkThe network is configured in the shape of a circle with each node connecting to the next node. Messages travel around the circle in one direction. Each node examines the message and uses it or regenerates it and passes it to the next node
Ring NetworkThe network is configured in the shape of a circle with each node connecting to the next node. Messages travel around the circle in one direction. Each node examines the message and uses it or regenerates it and passes it to the next node
Bus NetworkThe network is configured in the shape of an open-ended line with all nodes or workstations connected to the bus individually.
Bus NetworkThe network is configured in the shape of an open-ended line with all nodes or workstations connected to the bus individually.
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Network Hardware and Software (Network Topologies)
Star Network
Ring Network
Bus Network
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Network Hardware and Software (Protocols)
ProtocolsAgreed-upon formats for transmitting data between connected computers
ProtocolsAgreed-upon formats for transmitting data between connected computers
Open Systems Interconnection (OSI)Is a protocol that represents a group of tasks as seven successive layers that allow computers to communicate
Open Systems Interconnection (OSI)Is a protocol that represents a group of tasks as seven successive layers that allow computers to communicate
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Network Hardware and Software (Hardware)
Connectivity HardwareThe hardware that allows computers to be physically connected to different types of networks
Connectivity HardwareThe hardware that allows computers to be physically connected to different types of networks
Common Connectivity Hardware• Connectors • Network Interface Cards (NICs)• Modems• Repeaters• Hubs• Bridges• Multiplexers• Routers• Gateways
Common Connectivity Hardware• Connectors • Network Interface Cards (NICs)• Modems• Repeaters• Hubs• Bridges• Multiplexers• Routers• Gateways
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Network Hardware and Software (Hardware)
ConnectorsUsed to terminate cables in order to be plugged into a network interface card or another network component
ConnectorsUsed to terminate cables in order to be plugged into a network interface card or another network component
Network Interface CardA PC expansion board with its own unique identifier that plugs into a computer allowing it to be connected to a network
Network Interface CardA PC expansion board with its own unique identifier that plugs into a computer allowing it to be connected to a network
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Network Hardware and Software (Hardware)
Modem (Modulator/Demodulator)Enables computers to connect and transmit data over phone lines by converting the sending computer’s digital signals to analog and back again for the receiving computer
Modem (Modulator/Demodulator)Enables computers to connect and transmit data over phone lines by converting the sending computer’s digital signals to analog and back again for the receiving computer
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Network Hardware and Software (Hardware)
RepeaterA network device used to regenerate or replicate a signal as it weakens when traveling across a network
RepeaterA network device used to regenerate or replicate a signal as it weakens when traveling across a network
HubsA central point of connection between media segments enabling network extension to accommodate more PCs
HubsA central point of connection between media segments enabling network extension to accommodate more PCs
BridgesUsed to connect two different LANs or two segments of the same LAN by forwarding traffic between segments
BridgesUsed to connect two different LANs or two segments of the same LAN by forwarding traffic between segments
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Network Hardware and Software (Hardware)
RouterAn intelligent device used to connect two or more individual networks. When it receives a signal, it looks up the address and passes it to the appropriate network
RouterAn intelligent device used to connect two or more individual networks. When it receives a signal, it looks up the address and passes it to the appropriate network
GatewaysThis device performs a protocol conversion so that different networks can communicate even though they speak different languages
GatewaysThis device performs a protocol conversion so that different networks can communicate even though they speak different languages
MultiplexerUsed to share a communications line among a number of users by converting and combining signals from multiple users for simultaneous transmission over a single line
MultiplexerUsed to share a communications line among a number of users by converting and combining signals from multiple users for simultaneous transmission over a single line
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