Internet Technology

INSY402

S.A.Idowu

email:[e-mail]

1

Lesson1,2 and 3
 Internet
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Network Edge
Network Core

 Core Network Switching Schemes
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Circuit Switching
Packet Switching (pipelining)

 Network Delay
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Nodal Processing Delay
Queuing Delay
Transmission Delay
Propagation Delay

2

OSI 7-Layer Model
In the 70's, computer networks were ad hoc, vendor-specific
Open Systems Interconnection model

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developed by the ISO (International Organization for Standardization) in 1984 provides an abstract model of networking divides the tasks involved in moving information between networked computers into 7 task groups each task group is assigned a layer

Each layer is reasonably self-contained, so

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can be implemented independently changes/updates to a layer need not effect other layers 3

Protocol Layers
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Application layer
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describes how applications will communicate
e.g., HTTP, FTP, Telnet, SMTP

Presentation layer
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describes the form of data being transferred & ensures that it will be readable by receiver
e.g., floating point formats, data compression, encryption

Session layer
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describes the organization of large data sequences & manages communication session
e.g., coordinates requests/responses (“traffic flow”)

Transport layer
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describes the quality and nature of data delivery
e.g., how retransmissions are used to ensure delivery

Network layer
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describes how a series of exchanges over various data links can deliver data across a network
e.g., addressing and routing

Data Link layer
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describes the logical organization of data bits transmitted on a particular medium e.g., frame sequencing, error notification

Physical layer:
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describes the physical & electrical properties of the communications media e.g., voltage levels, data rates, max distances
4

Protocols
– Protocol
• Architecture