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CHAPTER 1 EXPLORE THE NETWORK - Coggle Diagram
CHAPTER 1
EXPLORE THE NETWORK
1.1.1 EXPLAIN LANs, WANs & INTERNET
1.1.2 HOW TO DESCRIBE NETWORKING TECHNOLOGIES ARE CHANGING THE HOME ENVIROMENT
ADVANTAGE OF COMPUTER NETWORK
NETWORK ENABLE MUTIPLE USER TO SHARE RESOURCE LIKE DATA AND DEVICES
SAVES MONEY
SAFE TIME
NETWORK ALLOW US TO MANAGE OR ADMINISTER, RESOURCES ON MULTIPLE COMPUTERS IN FROM A CENTRAL LOCATION
NETWORKING TECHNOLOGIES AT HOME HAS NO BOUNDARIES.
FOR EXAMPLE WE OR OUR FAMILY CAN LEARN , COMMUNICATE , WORK AND PLAY
DISADCANTAGE OF COMPUTER NETWORK
NETWORK HARDWARE , SOFTWARE AND SETUP COSTS
HARDWARE AND SOFTWARE MANAGEMENT AND ADMINISTION COSTS
UNDESIRABLE SHARING
ILLEGAL OR UNDESIRABLE BEHAVIOUR
DATA SECURITY CONCERN
1.1.3 Describe how host can be used as clients, server or both.
Client
A computer on a network that requests resources or services from another computer on a network.
Also acts as server which refers to the human user of a client workstation or to client software installed on the workstation.
Workstation
A personal computer such as desktop or a laptop which may connected to a network or not.
Most clients are workstations computers
Server
A computer on the network that manages shared resources.
More processing power, memory and hard disk space than clients
Run network operating software that can manage not only data but also users, groups, security and applications on the network.
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.
NEtwork Interface Card (NIC)
The device inside the computer thats connects a computer to the network media.
Allowing it to communicate with other computers
Host
A computer that enables resource sharing by others computer on the same network
Fundamental of a network models
Peer-to-Peer Networks (P2P)
DIsadvantage
No centralized administration
Not as secure
Not scalable
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Advantage
Easy to setup
Less complexity
Lower cost since network devices and dedicated servers may not be required
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Client/Server Networks
Another way of designing a network is to use a central computer which known as server; to facilitate communication and resource sharing between other computers on the network which known as clients.
A network that uses a server to enable clients to share data, data storage space and devices is known as a client/server network.
A clients/server architectureis sometimes used to refer to the design of a network in which clients rely on a servers for resource sharing and processing.
Node
A client, server or other device that can communicate over a network and it identified by a unique number which known as network address.
Connectivity Devices
A specialized devices that allows multiple networks or multiple parts of one network to connect and exchange data.
Backbone
The part of a network to which segments and significant shared devices such as routers, switches and servers connect.
Sometimes referred to as "a network of networks" because of its role in interconnecting smaller parts of LAN or WAN.
Segment
A part of a network which usually a segment is composed of a group of nodes that use the same communications channelfor all thier traffic.
Topology
Physical layout of a computer
Topologies vary according to the needs of the organization and available hardware and expertise.
Networks can be arranged in a ring, bus or star formation which is the most common.
Protocol
A format for communicationbetween networked devices.
For example, some protocols ensure that data are transferred in sequence and without error from one node on the network to another.
Transmission media
The means through which data are transmitted and received.
May be physical such as wire or cable or atmospheric (wireless) such as radio waves.
1.1.5 Four Basic Requirements Of A Reliable Network.
Scalability
Thousands of new users and service providers connect to the Internet each week. In order for the Internet to support this rapid amount of growth, it must be scalable.
A scalable
network can expand quickly to support new users and applications without affecting the performance of the service being delivered to existing users.
Quality of Service (QoS)
Quality of service is also an ever-increasing requirement of networks today. New applications available to users over internetworks, such as voice and live video transmissions
Fault Tolerance
The expectation is that the Internet is always available to the millions of users who rely on it. This requires a network architecture that is built to be fault tolerant.
. A fault-tolerant network is one that limits the effect of a failure, so that the fewest number of devices are affected by it. It is also built in a way that enables quick recovery when such a failure occurs.
Fault-tolerant networks depend on multiple paths between the source and destination of a message. If one path fails, the messages can be instantly sent over a different link. Having multiple paths to a destination is known as redundancy.
Security
Securing a network infrastructure includes physically securing devices that provide network connectivity, and preventing unauthorized access to the management software that resides on those devices.
1.1.4 How LANs and WANs interconect to the internet
Network of many sizes
Small Office Network
World Wide Network
Small Home Network
Medium to Large Network
Types Of Networks
Two most common types
Local Area Network (LAN)
Wide Area Network (WAN)
Other Types
Wireless LAN (WLAN)
Storage Area Network (SAN)
Metropolitan Area Network (MAN)
Personal Area Network (PAN)
The Internet, Intranet and Extranet
Internet
- Connecting a computer to any other computer anywhere in the world
Intranet
- Shared content accessed by members within a single organization
Extranet
- Shared content accessed by groups through cross-enterprise boundaries
1.1.1 Define the Computer Network
Computer Networks Definition
“Chain of interconnected computers” by Oxford Dictionary
"A connected computers for communication of processing" by Knott, Waites and Callaghan, Comp. Studies
"A set of devices (nodes) connected by media links" by Forouzan, Data Communications and Networking
Computer Networks
A network is a group of computers and other devices (such as
printers) that are connected by some type of transmission media
A network 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 a combination of cable, phone lines, and celular links.
They might communicate through copper wires, fiber-optic cable,
or radio waves as transmission media.
Topic 1.3 Interpret reference model of OSI and TCP/IP
1.3.1 Type of rules that are necessary to successfully communicate.
Communication Fundamentals
Message source (message)
Transmitter (signal)
Transmission medium
Receiver (signal)
Message Destination (message)
Relationship between 5 components
Main elements of data communication systems
Message - the information to be communicated (text, pictures, audio, video)
Sender - a device which sends the data messages (computer, workstation, telephone handset)
Receiver - a device which receives the data messages (computer, workstation, telephone handset)
Transmission Medium - a physical path by which a message travels from sender to receiver (twisted-pair wire, coaxial cable, radio waves)
Protocol - a set of rules that governs the data communications. It is a must to have protocol in communication system so that the devices can communicate each other
Rule Establishment
Protocols are necessary for effective communication
An identified sender and receiver
Common language and grammar
Speed and timing of delivery
Confirmation or acknowledgment requirements
Protocols define:
Message encoding
Message delivery options
Message Formatting and Encapsulation
Message Timing
Message Size
Message Encoding
Encoding between hosts must be in
appropriate format for the medium.
Messages are first converted into bits by
the sending host.
Each bit is encoded into a pattern of
sounds, light waves, or eletrical impulses depending on the network media
The destination host receives and decodes
the signals in order to interpret the message.
Message Source
Encoder
Transmitter
Transmission Medium "The Channel"
Receiver
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Message Formatting and Encapsulation
There is an agreed format for letters and addressing letters which is required for proper delivery.
Putting the letter into the addressed envelope
is called encapsulation.
Each computer message is encapsulated in a specific format, called a frame, before it is sent over the network
A frame acts like an envelope providing
destination address and source address.
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Message Size
Humans break long messages into smaller parts or
sentences.
Long messages must also 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.
A receiving host will reconstruct multiple frames
into the original message.
Message Timing
Access Method
Hosts on a network need to know when to begin sending messages and how to respond when collisions occur.
Flow Control
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Message Delivery Option
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Communication Method
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1.3.3 How the TCP/IP model and the OSI model are used to facilitate standardization in communication process.
OSI model and TCP/IP model comparison
OSI MODEL
7.Application
6.Presentation
5.Session
4.Transport
3.Network
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TCP/IP MODEL
Application
Transport
Internet
Network Access
TCP/IP PROTOCOL SUITE
HTTP,DNS,DHCP,FTP
TCP,UDP
IPv4,IPv6,ICMPv4,ICMPv6
PPP,FRAME RELAY, ETHERNET
REFERENCE MODELS
: In the OSI model, the network access layer and the application layer of the TCP/IP model are further divided to describe discrete functions that must occur at these layers
The OSI Reference Model
(4) Transport
Defines services to segment, transfer, and reassemble the data.
Protocol Data Unit (PDU):
Segment
(3) Network
Provides services to exchange the individual pieces of data over the network between identified end devices.
Protocol Data Unit (PDU):
Packet
(5) Session
Provides services to the presentation layer to organize its dialogue and to manage data exchange.
Protocol Data Unit (PDU):
Message
(2) Data Link
Provides methods for exchanging data frames between devices over a common media.
Protocol Data Unit (PDU):
Frame
(6) Presentation
Provides for common representation of the data.
Protocol Data Unit (PDU):
Message
(1) Physical
Describes the mechanical, electrical, functional, and procedural means to transmit bits across physical connections.
Protocol Data Unit (PDU):
Bit
(7) Application
Contains protocols used for process-to-process communications.
Protocol Data Unit (PDU):
Message
The Benefits of Using a Layered Model
Assisting in protocol design since protocols at each layer have defined functions.
Fostering competition because products from different vendors can work together
Preventing technology changes in one layer from affecting other layers.
Providing a common language to describe networking functions and capabilities
OSI model and TCP/IP model comparison
SIMILARITIES
share similar architecture
share a common application layer
Both models have comparable transport and network layers
Knowledge of both model required by networking professionals
DIFFERENCES
protocol standard
combines the presentation and session layer issues into its application layer
combines the OSI data link and physical layers into the network access layer
a simple model
1.3.2 Why protocols are necessary in the network communication
Protocol Interaction
Communication between a web server and web client is an example of an interaction between several protocols
TCP - transport protocol that manages the individual conversations
IP – encapsulates the TCP segments into packets, assigns addresses, and delivers to the destination host.
HTTP - an application protocol that governs the way a web server and a web client interact
Ethernet - allows communication over a data link and the physical transmission of data on the network media
Rules that Govern Communication
implemented by hosts and networking devices in software, hardware or both
viewed in terms of layers, with each higher level services depending on the functionality defined by the protocols shown in lower levels.
Protocol Suites and Industry Standards
A protocol suite is a set of protocols that work together to provide comprehensive network communication services
May be specified by a standards organization or developed by a vendor
The TCP/IP protocol suite is an open standard, the protocols are freely available, and any vendor is able to implement these protocols on their hardware or in their software
Development of TCP/IP
Advanced Research Projects Agency Network (ARPANET) was the predecessor to today’s Internet
ARPANET was funded by the U.S. Department of Defense for use by universities and research laboratories
TCP/IP Communication Process
When sending data from a web server to a client the encapsulation procedure would be as follows:
The webserver prepares the Hypertext Markup Language (HTML) page. The HTTP application layer protocol sends the data to the transport layer
The transport layer breaks the data
into segments and identifies each.
Next the IP source and destination addresses are added, creating an IP Packet
The Ethernet information is then added creating the Ethernet Frame, or data link frame
This frame is delivered to the nearest router along the path towards the web client. Each router adds new data link information before forwarding the packet.
Among the protocols for successful human communication are:
Identification of sender and receiver
Agreed-upon medium or channel (face to face, telephone, letter, photograph)
Appropriate communication mode (spoken, written, illustrated, interactive or one way)
Common language
Grammar and sentence structure
Speed and timing of delivery
TCP/IP Communication Process (Cont.)
When receiving the data link frames from the web server, the client processes and removes each protocol header in the opposite order it was added:
Then the Transport layer header
Finally the HTTP information is processed and sent to the client’s web browser
Then the IP header
First the Ethernet header is
removed
Network Protocols
define a common format and set of rules exhanging messages between devices
networking protocols are Hypertext Transfer Protocols (HTTP), Transmission Control Protocols (TCP), and Internet Protocols (IP)
The role of protocols
how the message is formatted or structured
networking devices share information about pathways with other network
How and when error and system messages are passed between devices
The setup and termination of data transfer sessions
