Computer Network

dingdongboomΔίκτυα και Επικοινωνίες

27 Οκτ 2013 (πριν από 4 χρόνια και 14 μέρες)

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Computer Network

Why Computer Network ???


Stand alone Computer ….


FOR WHAT ???

Something interesting from
Computer Network ???


Easiness


No distance


Mobility


Efficient


Network Administrator,…


Advantages


Good salary


Control other peoples


Faster than others


Relax


Disadvantages


ERROR
, then people
want to kill YOU !!!

Open System Interconnection
(OSI)


A model defines the stages or
tasks of a protocol as it
prepares to send data


Open meaning standards
available to all.


The model is divided into
seven distinct layers


Each subsequent layer should
perform a well
-
defined function
and the layer boundaries are
designed to minimize the
information flow across the
interfaces

OSI Model Layers


Application Layer


Provides a user interface (examples: HTTP, SMTP)


Includes file, print, database, app. Services


Presentation Layer


Presents the data (example: JPEG)


Includes encryption, compression and translation
services


Session Layer


Keeps different applications data separate

OSI Model Layers


Transport Layer


Provides reliable delivery


Performs error detection


Includes end to end connection


Network Layer


Provides logical addressing


Routing layer


OSI Model Layers



Data Link Layer


Combines packets into bytes then into frames


Performs error detection (not correction)


Provides Media access addressing (point
-
to
-
point)


Media Access Control and Data Link Control


Physical Layer


Moves bits between devices

Keys Layers of the OSI Model

OSI Model and Protocols

Network Devices


Wire



Wireless

Router, Switch, Hub, Modem, …

TCP/IP

TCP/IP

Network Security


Firewall

Operating Systems

Server
-

Client

Certificate


Thank You…

IPX
-

Internet Protocol Exchange (networking)

RIP
-

Routing Information Protocol

IGRP
-

Interior Gateway Routing Protocol (Cisco Systems routing protocol)

OSPF
-

Open Shortest Path First