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Protocols and Standards. Protocols Standards Standards Organizations. Definition and Need for Protocol Elements of protocols Syntax Semantics Timing. Protocols. Standards and standards Marking organization Categories of Standards - PowerPoint PPT Presentation
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ProtocolsProtocols and Standardsand Standards
• Protocols
• Standards
• Standards Organizations
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Protocols Definition and Need for Protocol
Elements of protocols Syntax Semantics Timing
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Standards
Standards and standards Marking organization
Categories of Standards De factor - meaning by fact or by
conversion De jure - meaning by law or organization
Standards Organizations Standards creation committees (ISO, ITU-
T, ANSI,IEEE & EIA) Forums Regulatory agencies (TRCA)
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Standards
Standards
De jure(by law)
De factor(by fact)
Proprietary Non-Proprietary
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NetworkModels
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Communication Model/Network Model
Model: -a frame or reference or set of guidelines on which communicating devices can understand each other.
Network Model: Open Systems Interconnection – OSI
Model Internet Model
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OSI is used as the theoretical model for how communication between devices, such as computer takes place. It define the way in which device interact
• There are seven layers in the OSI model: application, Presentation,
Session, Transport, Network, Data Link and Physical.
• These layers make up a framework that defines the way in which physical
hardware, media and software work together to communicate.
• Each layer of the OSI model is independent from every other in its purpose
and responsibilities.
• Each must do its own job, as well as provide services to the layers above
and below it.
• The model creates framework to understand how network communication
is taking place, as well as aid in troubleshooting problems that arise within
a network.
• The OSI model provides a structure for software programmers and Equipment
manufacturers to develop product that will work together [interoperability]
OSI Model
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These services can be divided into horizontal and vertical communication models.
The communication between layers in the same device is an
example of vertical communication model.
In the horizontal model, communication is between the same
layer on different devices.
This horizontal model is based on protocols that works at
specific layers of the model.
The top five layers of the OSI model are represented in software, while the lower layers are based on hardware.
OSI Model
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Sending a letter
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Application layer
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Presentation layer
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Session layer
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Transport layer
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Network layer
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Data link layer
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Physical layer
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Summary of layer functions
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Internet Model
Internet model is made up of five [5] layers
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An exchange using the Internet model
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Physical layer
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Physical layer
Physical layer is responsible for actual physical connection between devices.
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The physical layer is responsible for transmitting individual bits from one
node to the next.
Note:Note:
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Data link layer
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Data link Layer
Data link layer has two sublayers and each provides its own
services in the OSI model
Data link Sublayers
Logical Link Control [LLC]
Media Access Control [MAC]
LLC Sublayer: provides the interface between the media access
method and the network layer protocol.
MAC Sublayer: Is responsible for the connection to the physical
media
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The data link layer is responsible for transmitting frames from
one node to the next.
Note:Note:
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Node-to-node delivery
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Network layer
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Network Layer
This layer is responsible for the addressing and delivery of
packet.
Network address is a logical address based on numbering
scheme that is independent of a devices hardware or location.
Functions of the Network layer
Add the network address to the packet
Map the network to the device physical address
Determine the best path for the packet
Ensure that the packet is in the correct format for the
destination network
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The network layer is responsible for the delivery of packets from the original source to the final destination.
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Source-to-destination delivery
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Transport layer
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Transport Layer The function of the transport layer is to ensure that data
packets it receives from the session layer arrive reliably. Two type of transmission
Connection Oriented Connectionless
Transport layer also has the job of managing the speed of communication between devices: flow control
Features of Connection Oriented transmission Reliability Slower communication Packets are resent if a packet is un recognized or is not
received Features of connectionless transmission
Little or no Reliability Faster transmission Packet are not retransmitted
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The transport layer is responsible for delivery of a message from one process
to another.
Note:Note:
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Reliable process-to-process delivery of a message
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Application layer
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Application layer is the service provider. It gives service to the user of
the network.
Application layer works with the applications you use to communicate
over the network. Example: SMTP-simple mail transfer protocol to send
e-mail, HTTP (HyperText Transfer Protocol) to access the web page while
surfing the Internet, FTP (file transfer protocol) transfer protocol to
download a file from an FTP server.
Application Services:
File services
Electronic-mail services
Network printing services
Application services
Database services
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The application layer is responsible for providing services to the user.
Note:Note: