year 1 - chapter 2 / cisco 1 - module 2 networking fundamentals · 2020. 5. 7. · wan technologies...
TRANSCRIPT
Networking Fundamentals
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Networking Fundamentals
Objectives
• Networking terminology• Bandwidth• Networking models
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• Networking terminology• Bandwidth• Networking models
Data Networks
• Developed as a result of business applications that werewritten for microcomputer
• The microcomputers were not connected so there wasno efficient way to share data among them
• It was not efficient or cost-effective for businesses to usefloppy disks to share data
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• Developed as a result of business applications that werewritten for microcomputer
• The microcomputers were not connected so there wasno efficient way to share data among them
• It was not efficient or cost-effective for businesses to usefloppy disks to share data
• Businesses needed a solution that would successfullyaddress the following three problems:
- how to avoid duplication of equipment and resources- how to communicate efficiently
- how to set up and manage a network
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• Businesses needed a solution that would successfullyaddress the following three problems:
- how to avoid duplication of equipment and resources- how to communicate efficiently
- how to set up and manage a network
• Data networking solutions– Local-area networks– Wide-area networks
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Networking Devices
• Equipment that connectsdirectly to a networksegment is referred to asa device. These devicesare broken up into twoclassifications. The firstclassification is end-userdevices. The secondclassification is networkdevices.
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• Equipment that connectsdirectly to a networksegment is referred to asa device. These devicesare broken up into twoclassifications. The firstclassification is end-userdevices. The secondclassification is networkdevices.
Network Topology
• Network topology definesthe structure of thenetwork. The physicaltopology, which is theactual layout of the wireor media, and the logicaltopology, which defineshow the media isaccessed by the hosts forsending data.
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• Network topology definesthe structure of thenetwork. The physicaltopology, which is theactual layout of the wireor media, and the logicaltopology, which defineshow the media isaccessed by the hosts forsending data.
Physical Topology• A bus topology uses a single backbone cable that is
terminated at both ends. All the hosts connect directly tothis backbone
• A ring topology connects one host to the next and thelast host to the first. This creates a physical ring of cable.
• A star topology connects all cables to a central point.• An extended star topology links individual stars together
by connecting the hubs or switches.• A hierarchical topology is similar to an extended star.
However, instead of linking the hubs or switchestogether, the system is linked to a computer that controlsthe traffic on the topology
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• A bus topology uses a single backbone cable that isterminated at both ends. All the hosts connect directly tothis backbone
• A ring topology connects one host to the next and thelast host to the first. This creates a physical ring of cable.
• A star topology connects all cables to a central point.• An extended star topology links individual stars together
by connecting the hubs or switches.• A hierarchical topology is similar to an extended star.
However, instead of linking the hubs or switchestogether, the system is linked to a computer that controlsthe traffic on the topology
Logical Topology
Broadcast topology• Each host sends its data to all other hosts on the
network medium• There is no order that the stations must follow to
use the network• It is first come, first serve. Ethernet works this
way.
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Broadcast topology• Each host sends its data to all other hosts on the
network medium• There is no order that the stations must follow to
use the network• It is first come, first serve. Ethernet works this
way.
Token passing
• An electronic token is passed sequentially to each host• When a host receives the token, that host can send data
on the network• If the host has no data to send, it passes the token to the
next host and the process repeats itself
Examples: Token Ring and Fiber Distributed DataInterface (FDDI)
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Token passing
• An electronic token is passed sequentially to each host• When a host receives the token, that host can send data
on the network• If the host has no data to send, it passes the token to the
next host and the process repeats itself
Examples: Token Ring and Fiber Distributed DataInterface (FDDI)
Network Protocols
• A protocol is a formal description of a set of rules andconventions that govern a particular aspect of howdevices on a network communicate
• Protocol suites are collections of protocols that enablenetwork communication from one host through thenetwork to another host
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• A protocol is a formal description of a set of rules andconventions that govern a particular aspect of howdevices on a network communicate
• Protocol suites are collections of protocols that enablenetwork communication from one host through thenetwork to another host
• Rules are created and maintained by many differentorganizations and committees:
- The Institute of Electrical and Electronic Engineers (IEEE)- American National Standards Institute (ANSI)- Telecommunications Industry Association (TIA)- Electronic Industries Alliance (EIA)- International Telecommunications Union (ITU)
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• Rules are created and maintained by many differentorganizations and committees:
- The Institute of Electrical and Electronic Engineers (IEEE)- American National Standards Institute (ANSI)- Telecommunications Industry Association (TIA)- Electronic Industries Alliance (EIA)- International Telecommunications Union (ITU)
LANs
• Operate within a limited geographic area• Allow many users to access high-bandwidth media• Provide full-time connectivity to local services• Connect physically adjacent devices
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LAN Components
• Computers• Network interface cards• Peripheral devices• Networking media• Network devices
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• Computers• Network interface cards• Peripheral devices• Networking media• Network devices
LAN Technologies
• Ethernet• Token Ring• Fiber distributed data interface (FDDI)
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LAN Devices
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WAN Technologies
• Analog modems• Integrated Services Digital Network (ISDN)• Digital Subscriber Line (DSL)• Frame Relay• Asynchronous Transfer Mode (ATM)• T (US) and E (Europe) carrier series: T1, E1, T3, E3• Synchronous Optical Network (SONET)
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• Analog modems• Integrated Services Digital Network (ISDN)• Digital Subscriber Line (DSL)• Frame Relay• Asynchronous Transfer Mode (ATM)• T (US) and E (Europe) carrier series: T1, E1, T3, E3• Synchronous Optical Network (SONET)
WAN Devices
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Metropolitan-Area Networks(MANs)
• A MAN is a network that spans a metropolitan area suchas a city or suburban area.
• A MAN usually consists of two or more LANs in acommon geographic area.
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• A MAN is a network that spans a metropolitan area suchas a city or suburban area.
• A MAN usually consists of two or more LANs in acommon geographic area.
Storage-Area Networks (SANs)• A SAN is a dedicated,
high-performancenetwork used to movedata between servers andstorage resources
• Because it is a separate,dedicated network, itavoids any traffic conflictbetween clients andservers
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• A SAN is a dedicated,high-performancenetwork used to movedata between servers andstorage resources
• Because it is a separate,dedicated network, itavoids any traffic conflictbetween clients andservers
Virtual Private Networks (VPNs)
• A VPN is a private network that is constructed within apublic network infrastructure such as the global Internet
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Benefits of VPNs
• A VPN is a service that offers secure, reliableconnectivity over a shared public network infrastructuresuch as the Internet.
• VPNs maintain the same security and managementpolicies as a private network.
• They are the most cost-effective method of establishinga point-to-point connection between remote users andan enterprise customer's network.
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• A VPN is a service that offers secure, reliableconnectivity over a shared public network infrastructuresuch as the Internet.
• VPNs maintain the same security and managementpolicies as a private network.
• They are the most cost-effective method of establishinga point-to-point connection between remote users andan enterprise customer's network.
VPN Types
There are three main types of VPNs:• Intranet VPNs• Extranet VPNs• Access VPNs
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There are three main types of VPNs:• Intranet VPNs• Extranet VPNs• Access VPNs
Intranets and Extranets
• Intranets are designed topermit access by users whohave access privileges tothe internal LAN of theorganization
• Extranets refer toapplications and servicesthat are Intranet based, butthat use extended, secureaccess to external users orenterprises
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• Intranets are designed topermit access by users whohave access privileges tothe internal LAN of theorganization
• Extranets refer toapplications and servicesthat are Intranet based, butthat use extended, secureaccess to external users orenterprises
Bandwidth
• Bandwidth is defined as the amount of information that canflow through a network connection in a given period of time
• Bandwidth is limited by the laws of physics and by thetechnologies used to place information on the media
Example: Bandwidth of a conventional modem is limited toabout 56 kbps
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• Bandwidth is defined as the amount of information that canflow through a network connection in a given period of time
• Bandwidth is limited by the laws of physics and by thetechnologies used to place information on the media
Example: Bandwidth of a conventional modem is limited toabout 56 kbps
Importance of Bandwidth
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Digital Bandwidth
• Two analogies that describe digital bandwidth– Width of a pipe– Number of lanes on a highway
• Media bandwidth differences– Category 5 UTP – 100 meters maximum physical
distance– Multimode (62.5/125um) optical fiber – 2000
meters– Modem – 56 kbps = 0.056 Mbps– T1 – 1.544 Mbps
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• Two analogies that describe digital bandwidth– Width of a pipe– Number of lanes on a highway
• Media bandwidth differences– Category 5 UTP – 100 meters maximum physical
distance– Multimode (62.5/125um) optical fiber – 2000
meters– Modem – 56 kbps = 0.056 Mbps– T1 – 1.544 Mbps
Throughput
• Refers to actual measured bandwidth, at a specific time ofday, using specific Internet routes, and while a specific setof data is transmitted on the network
• Throughput is often far less than the maximum possibledigital bandwidth of the medium that is being used
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• Refers to actual measured bandwidth, at a specific time ofday, using specific Internet routes, and while a specific setof data is transmitted on the network
• Throughput is often far less than the maximum possibledigital bandwidth of the medium that is being used
• Factors that determine throughput are:
- Internetworking devices- Type of data being transferred- Network topology- Number of users on the network- User computer- Server computer
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• Factors that determine throughput are:
- Internetworking devices- Type of data being transferred- Network topology- Number of users on the network- User computer- Server computer
Bandwidth Pipe Analogy
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Bandwidth Highway Analogy
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Bandwidth Measurements
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Media Bandwidth
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Digital Transfer Calculation
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Digital vs. Analog
• Analog bandwidth is measured by how much of theelectromagnetic spectrum is occupied by each signal
• In digital signaling, all information is sent as bits,regardless of the kind of information it is.
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• Analog bandwidth is measured by how much of theelectromagnetic spectrum is occupied by each signal
• In digital signaling, all information is sent as bits,regardless of the kind of information it is.
Using Layers to DescribeCommunication
• Source, destination, and data packets– All communications originate at a source and travel
to a destination.– Information that travels on a network is referred to as
a data, packet, or data packet.
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• Source, destination, and data packets– All communications originate at a source and travel
to a destination.– Information that travels on a network is referred to as
a data, packet, or data packet.
Using Layers to DescribeCommunication
• Media– Telephone wires (UTP)– Category 5 UTP (used for 10BASE-T Ethernet)– Coaxial cables– Optical fibers (thin glass fibers that carry light)
• Protocol– All devices on a network need to speak the same
language.– Set of rules that makes communication both possible
and more efficient.
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• Media– Telephone wires (UTP)– Category 5 UTP (used for 10BASE-T Ethernet)– Coaxial cables– Optical fibers (thin glass fibers that carry light)
• Protocol– All devices on a network need to speak the same
language.– Set of rules that makes communication both possible
and more efficient.
The Purpose of the OSI ReferenceModel
• It breaks network communication into smaller, simplerparts that are easier to develop
• It facilitates standardization of network components toallow multiple-vendor development and support
• It allows different types of network hardware and softwareto communicate with each other
• It prevents changes in one layer from affecting the otherlayers so that they can develop more quickly
• It breaks network communication into smaller parts tomake learning it easier to understandCopyright 2008
• It breaks network communication into smaller, simplerparts that are easier to develop
• It facilitates standardization of network components toallow multiple-vendor development and support
• It allows different types of network hardware and softwareto communicate with each other
• It prevents changes in one layer from affecting the otherlayers so that they can develop more quickly
• It breaks network communication into smaller parts tomake learning it easier to understand
Seven Layers of theOSI Reference Model
• Layer 7: Application• Layer 6: Presentation• Layer 5: Session• Layer 4: Transport• Layer 3: Network• Layer 2: Data link• Layer 1: Physical
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• Layer 7: Application• Layer 6: Presentation• Layer 5: Session• Layer 4: Transport• Layer 3: Network• Layer 2: Data link• Layer 1: Physical
Why a Layered Model?
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Layers with Functions
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The Seven Layers of the OSIReference Model
• The application (upper) layers– Layer 7: Application– Layer 6: Presentation– Layer 5: Session
• The data-flow (lower) layers– Layer 4: Transport– Layer 3: Network– Layer 2: Data link– Layer 1: Physical
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• The application (upper) layers– Layer 7: Application– Layer 6: Presentation– Layer 5: Session
• The data-flow (lower) layers– Layer 4: Transport– Layer 3: Network– Layer 2: Data link– Layer 1: Physical
The Application (Upper) Layers• Application
– User interface– Examples – Telnet, HTTP
• Presentation– How data is presented– Special processing, such as encryption– Examples – ASCII, EMCDIC, JPEG
• Session– Keeping different applications’ data separate– Examples – Operating system/application access
scheduling
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• Application– User interface– Examples – Telnet, HTTP
• Presentation– How data is presented– Special processing, such as encryption– Examples – ASCII, EMCDIC, JPEG
• Session– Keeping different applications’ data separate– Examples – Operating system/application access
scheduling
The Data-Flow (Lower) Layers
• Transport– Reliable or unreliable delivery– Error correction before transmit– Examples: TCP, UDP, SPX
• Network– Provide logical addressing which routers use for path
determination– Examples: IP, IPX
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• Transport– Reliable or unreliable delivery– Error correction before transmit– Examples: TCP, UDP, SPX
• Network– Provide logical addressing which routers use for path
determination– Examples: IP, IPX
The Lower Layers (cont.)
• Data link– Combines bits into bytes and bytes into frames– Access to media using MAC address– Error detection not correction– Examples: 802.3/802.2, HDLN
• Physical– Moves bits between devices– Specifies voltage, wire speed, and pin out cables– Examples: EIA/TIA-232, V.35
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• Data link– Combines bits into bytes and bytes into frames– Access to media using MAC address– Error detection not correction– Examples: 802.3/802.2, HDLN
• Physical– Moves bits between devices– Specifies voltage, wire speed, and pin out cables– Examples: EIA/TIA-232, V.35
The OSI Model
• Application – Think of browsers.• Presentation – Think of common data format.• Session – Think of dialogs and conversations.• Transport – Think of flow control and reliability.• Network – Think of path selection, routing, and logical
addressing.• Data Link – Think of frames and media access control.• Physical – Think of signals and media.
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• Application – Think of browsers.• Presentation – Think of common data format.• Session – Think of dialogs and conversations.• Transport – Think of flow control and reliability.• Network – Think of path selection, routing, and logical
addressing.• Data Link – Think of frames and media access control.• Physical – Think of signals and media.
Peer-to-Peer Communication
• For data to travel from the source to the destination,each layer of the OSI model at the source mustcommunicate with its peer layer at the destination.
• During this process, the protocols of each layerexchange information, called protocol data units (PDUs),between peer layers.
• Each layer of communication on the source computercommunicates with a layer-specific PDU, and with itspeer layer on the destination computer.
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• For data to travel from the source to the destination,each layer of the OSI model at the source mustcommunicate with its peer layer at the destination.
• During this process, the protocols of each layerexchange information, called protocol data units (PDUs),between peer layers.
• Each layer of communication on the source computercommunicates with a layer-specific PDU, and with itspeer layer on the destination computer.
The TCP/IP Reference Model
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TCP/IP Protocol Graph
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Applications
• FTP – File Transfer Protocol• HTTP – Hypertext Transfer Protocol• SMTP – Simple Mail Transfer Protocol• DNS – Domain Name System• TFTP – Trivial File Transfer Protocol
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• FTP – File Transfer Protocol• HTTP – Hypertext Transfer Protocol• SMTP – Simple Mail Transfer Protocol• DNS – Domain Name System• TFTP – Trivial File Transfer Protocol
OSI Model and TCP/IP Model
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Use of the OSI Model in the CCNACurriculum
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EncapsulationThe lower layers useencapsulation to putthe protocol data unit(PDU) from the upperlayer into its data fieldand to add headersand trailers that thelayer can use toperform its function.
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The lower layers useencapsulation to putthe protocol data unit(PDU) from the upperlayer into its data fieldand to add headersand trailers that thelayer can use toperform its function.
Names for Data at Each Layer
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De-Encapsulation
• When the data link layer receives the frame, itdoes the following:– It reads the physical address and other control
information provided by the directly connected peerdata link layer.
– It strips the control information from the frame,thereby creating a datagram.
– It passes the datagram up to the next layer, followingthe instructions that appeared in the control portion ofthe frame.
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• When the data link layer receives the frame, itdoes the following:– It reads the physical address and other control
information provided by the directly connected peerdata link layer.
– It strips the control information from the frame,thereby creating a datagram.
– It passes the datagram up to the next layer, followingthe instructions that appeared in the control portion ofthe frame.
Thank You
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