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CHAPTER 1 : EXPLORE THE NETWORK, Mauldorna - Coggle Diagram
CHAPTER 1 : EXPLORE THE NETWORK
GIBSON
1.1.4 How LANs and WANs interconnect to the internet?
Size of Network
Small Office or Home office networks
Medium to large networks
world wide networks
small home networks
Type of networks
Storage Area Network (SAN
Wireless LAN (WLAN)
Local Area Network (LAN)
Wide Area Network (WAN
Metropolitan Area Network (MAN)
Personal Area Network (PAN)
INTERNETS,INTRANETS,EXTRANETS
INTERNETS
iconnecting a computer to any other computer
anywhere in the world via dedicated routers and servers.
INTRANETS
shared content accessed by members within a single organization
EXTRANETS
shared content accessed by groups through cross
enterprise boundaries
1.1.5 BASIC REQUIREMENTS OF A RELIABLE NETWORK
FAULT TOLERANCE
one that limits the effect of a failure, so that the
fewest number of devices are affected by it.
SCALABILITY
expend quickly to support new users and applications without affecting the performance of the service
QUALITY OF SERVICE
an ever increasing requirement of
networks today.
SECURITY
Securing a network infrastructure includes physically securing
HOW THE TCP/IP MODEL AND OSI MODEL ARE USED TO FACILITATE STANDARDIZATION IN THE COMMUNICATION PROCESS
The Benefits of Using a Layered Model
Assisting in protocol design
Fostering competition because
Preventing technology changes
in one layer from affecting
Providing a common language
The OSI Reference Model
The TCP/IP Protocol Model
OSI Model and TCP/IP Model Comparison
wardina
1.3.1 types of rules that are necessary to successfully communicate
Communication Fundamentals
Main elements of data communication systems
Receiver
(the device which receives the data messages)
e.g : can be a computer, workstation, handphone
Sender
(the device which sends the data mesages)
e.g : can be a computer, workstation, handphone
Transmission Medium
(the physical path by which message travels from sender to receiver)
e.g : twisted-pair wire, coaxial cable, radio waves
Message
(the information to be communicated)
e.g of popular form : text, pictures, audio
Protocol
(a set of rules that governs the data communications)
Protocols
Rule establishment
protocols are necessary for effective communication include
an identified sender and receiver
common language and grammar
speed and timing of delivery
confirmation/acknowledgement requirements
Message Encoding
encoding between hosts must be in appropriate format for the medium
messages will first converted into BITS by the sending hosts
each bit is encoded into
a pattern of sounds, light waves or electrical impulses depending on the network media
Message Formatting and Encapsulation
similar to letters :
letters have an agreed format and addressing letters for a proper delivery
putting the letter into the addressed envelope is called
encapsulation
each computer message is
encapsulated
in a specific format called
frame
before it is sent over the network
frame
: acts like an envelope providing destination address and source address
Message Size
long messages must be broken into smaller pieces to travel across a network
each piece is sent in a separate frame
each frame has its own addressing information
receiving host will reconstruct multiple frames into the original message
Message Timing
Flow Control
source and destination hosts use flow control :
to negotiate correct timing to avoid overwhelming the destination
ensure information is received
Response Timeout
hosts on the network have rules :
to wait for responses
what action to take if response time occurs
Access Method
hosts on network need to know when to begin sending messages and how to respond when collisions occur
Message Delivery Options
Multicast Message
one-to-many delivery
only few people receive the message
Broadcast Message
one-to-all delivery
everyone receive the message
Unicast Message
one-to-one delivery
only one people receive the message
Communication Method
Source
(sender)
people, electronic devices etc that need to communicate a message to other individuals or devices
Destination
(receiver)
the destination receives the message and interprets it
Channel
(media)
provides the pathway over which the message can travel from source to destination
1.3.2 why protocols are necessary in network communication
Network Protocols
a common format and set of rules for exchanging messages between devices
e.g :
Hypertext Transfer Protocol (HTTP)
Transmission Control Protocol (TCP)
Internet Protocol (IP)
the role of protocols
the process by which networking devices share information about pathways with other networks
the setup and termination of data transfer sessions
how the message is formatted or structured
how and when error and system messages are passed between devices
protocol interaction
an example of interaction between protocols in a communication between web server and web client
HTTP
an application protocol
governs the way a web server and web client interact
TCP
a transport protocol
manages the individual conversations
IP
encapsulates the TCP segments into packets, assigns addresses and delivers to the destination host
Ethernet
allows communication over a data link and the physical transmission of data on the network media
Protocol Suites and Industry Standards
a set of protocols that work together to provide comprehensive network communication services
may be specified by a standard organizations or developed by a vendor
TCP/IP
an open standard protocol suite
freely availabe
any vendor can implement these protocols
Development of TCP/IP
Advanced Research Projects Agency Network (ARPANET)
the predecessor of today's Internet - IPv6
TCP/IP Communication Process
an example of sending message from a web server to web client
Web server prepares the HTML page. The HTTP app layer protocol sends the data to transport layer
Transport layer breaks the data into segments and identifies each
IP source and destination addresses are added , creating an IP Packet
Ethernet information then added and creating the Ethernet Frame or data link frame
The web client will processes and removes each protocol header in opposite order from the Ethernet to IP to Transport header and the HTTP information is processed and sent to client's web browser
Topic 1.1 Explain LANs, WAN,s and The Internet
1.1.1 Computer Networks Definition
Chain of interconnected computers - Oxford dictionary
A number of computers connected together for the purpose of communication of processing
Knott, Waites and Callaghan, Comp. Studies
A network
group of computers and other devices( such as printers ), connected by some type of transmission media.
can be as small as two computers connected by a cable in a home office or as large as several thousand computers connected across the world via combination of cable, phone lines and cellular links
they might communicate through copper wires, fiber-optic cable or radio waves as transmission media.
A network is a set of devices(nodes) connected by media links
-Forouzan, Data Communications and Networking
1.1.2 How networking technologies are changing the home environment
Network support the way we:
Learn
Communicate
Work
Play
Advantages of Computer Network
Networks enable multiple users to share resources (devices and data)
Saves money and time
Network allow to manage or administer, resources on multiple computers from a central location
Disadvantages of Computer Network
Network Hardware, Software and Setup Costs
Hardware and Software Management and Administration Costs
Undesirable Sharing
Illegal or Undesirable Behavior
Data Security concerns
1.1.3 How host devices can be used as clients, server or both.
Client/Server Network Elements
Client:
requests resources or services from another computer on a network
also act as server
The term client: human user of a client workstation or to client software installed on the workstation
Server:
manages shared resources
have more processing power, memory and hard disk space than clients
Server can manage not only data, but also users, groups, security and application on the network
Workstation:
A personal computer such as a desktop or laptop
which may or may not be connected to a network
most clients are workstation computers
Network Interface Card (NIC):
The device inside a computer that connects a computer to the network media
allowing it to communicate with others computers
Network Operating System (NOS):
The software that runs on a server and enables the server to manage data users, groups, security, applications and other networking functions
Example: Microsoft Window Server 2008 R2, Mac OS X Server, Unix and Linux OS
Host:
A computer that enable resource sharing by other computers on the same network
Node:
A client, server, or other device that can communicate over a network
which is identified by a unique number and known as its network address
Protocol:
communication between networked devices
Example: -some protocols ensure that data are transferred in sequenced
without error from one node on the network to another
Topology:
The physical layout of a computer network - according to the needs of the organization
available hardware and expertise
network can be arranged in a ring, bus or star formation (the most common )
Hybrid combination of these pattern are also possible
Transmission Media:
data are transmitted and received
may be physical, such as wire or cable, or atmospheric(wireless) such as radio waves
Connectivity Devices:
A specialized devices that allows multiple networks or multiple parts of one network
to connect and exchange data
Backbone:
segments and significant shared devices(such as routers, switches and servers) connect
sometimes referred to as "a network of networks"
its role in interconnecting smaller parts of a LAN or WAN
Segment:
A part of a network
composed of a group of nodes
use the same communications channel for all their traffic
Fundamental of Network Models
Peer-to-peer Networks (P2P)
Example :
Advantages:
Easy to set up
Less complexity
Lower cost since network devices and dedicated servers may not be required
used for simple task such as transferring file and sharing printers
Disadvantages:
No centralized administration
Not as secure
Not scalable
All devices may act as both clients and servers which can slow their performance
Client/ Server Networks
Another way of designing a network is to use a central computer and known as a server
to facilitate communication and resource sharing between other computers on the network and knows as clients
A network that uses a server to enable clients to share data, data storage and devices
Architecture:
used to refer: design of a network in which clients rely on servers for resource sharing and processing
Mauldorna
