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Chapter 1: Explore The Network, HAZIQ - Coggle Diagram
Chapter 1: Explore The Network
JAZRIN
CLIENT/ SERVER NETWORK ELEMENTS
CLIENT
A computer on the network that requests resources or services from another computer on a network.
Also can act as server (in some cases)
Client also can be human user of a client workstation or to client software installed on the workstation.
SERVER
A computer on the network that manages shared resources.
Usually have 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.
WORKSTATION
A personal computer (such as a desktop or laptop).
May or may not be connected to a network.
Most clients are workstation computers.
NETWORK INTERFACE CARD
The device inside a computer that connects a computer to the network media. Its allow to communicate with other computer.
NETWORK OPERATING SYSTEM
The software that runs on a server and enables the server to manage data, users, groups, security, applications and other networking functions.
For example: Microsoft Windows Server 2008 R2, Mac OS X Server, Unix and Linux OS.
HOST
A computer that enables resource sharing by other computers on the same network.
NODE
A client, server, or other device that can communicate over a network. Identified by a unique number, known as its network address.
CONNECTIVITY DEVICE
A specialized device 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 a LAN or WAN.
SEGMENT
A part of a network. Usually, composed of a group of nodes that use the same communications channel for all their traffic.
TOPOLOGY
The physical layout of a computer network. Topologies vary according to the needs of the organization and available hardware and expertise. Network be arrange in a ring, bus, star formation or hybrid
PROTOCOL
A format for communication between networked devices. Some protocols ensure that data are transferred in sequence and without error from one node on the network to another.
TRANSMISSION MEDIA
Which data are transmitted and received. May be physical, such as wire or cable, or atmospheric (wireless), such as radio waves.
Fundamental of Network Models
Peer to Peer
Advantages
Easy to set up
Less complexity
Low cost
Can be used for simple tasks
Disadvantages
No centralized administration
Not as secure
Slow performance
Client / Server Networks
Another way of designing a network is to use a central computer (known as a server), to facilitate communication and resource sharing between other computers on the network (which are known as clients).
A network that uses a server to enable clients to share data, data storage space, and devices.
Rules that Govern Communications
Protocol suites
Implemented by hosts and networking devices in software, hardware or both.
-Viewed in terms of layers, with each higher level service depending on the functionality defined by the protocols shown in the lower levels.
The protocol for successful human communication:
1.Identification of sender and receiver
2.Agreed-upon medium or channel (face-to-face, telephone, letter, photograph)
3.Appropriate communication mode (spoken, written, illustrated, interactive or one-way)
4.Common language
5.Grammar and sentence structure
6.Speed and timing of delivery
Network Protocol
Define a common format and set of rules for exchanging messages between devices.
Common networking protocols
Hypertext Transfer Protocol (HTTP)
Transmission Control Protocol (TCP)
Internet Protocol (IP).
Protocol Interaction
Communication between a web server and web client.
Example:
◦ HTTP - an application protocol that governs the way a web server and a web client interact.
TCP - transport protocol that 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 protocol suite
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
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) The predecessor for today’s Internet
Was funded by the U.S. Department of Defense for use by universities and research laboratories.
TCP/IP Communication Process
Sending data from a web server to a client the encapsulation procedure.
1.The web server prepares the Hypertext Markup Language (HTML) page. The HTTP application layer protocol sends the data to the transport layer.
2.The transport layer breaks the data into segments and identifies each.
3.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.
Receiving the data link frames from the web server, the client processes and removes each protocol header in the opposite order.
1.First the Ethernet header is removed
2.Then the IP header
3.Then the Transport layer header
4.Finally the HTTP information is processed and sent to the client’s web browser.
The Benefits of Using a Layered Model
1.Assisting in protocol design since protocols at each layer have defined functions.
2.Fostering competition because products from different vendors can work together.
3.Preventing technology changes in one layer from affecting other layers.
4.Providing a common language to describe networking functions and capabilities.
The OSI Reference Model
1.Application
Contains protocols used for process-to process communications.
2.Presentation
Provides for common representation of the data.
3.Session
Provides services to the presentation layer to organize its dialogue and to manage data exchange.
4.Transport
Defines services to segment, transfer, and reassemble the data. 5.Network
Provides services to exchange the individual pieces of data over the network between identified end devices.
6.Data Link
Provides methods for exchanging data frames between devices over a common media.
7.Physical
Describes the mechanical, electrical, functional, and procedural means to transmit bits across physical connections.
The TCP/IP Protocol Model
Created in the early 1970s for internetwork communications.
Open Standard.
Also called The TCP/IP Model or the Internet Model.
OSI Model and TCP/IP Model Comparison
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.
Similarities:
Share similar architecture.
Share a common application layer.
Both models have comparable transport and network layers.
Knowledge of both models is 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 simpler model.
ERIKA
1.1.1 Define the Computer Network
Computer Network Definition -chain of interconnected computers.-Oxford Dictionary
:pencil2: A network can be as small as two computer that connected by the a cable in at home office. They also can be large as several thousand computers that was connected across the world via cable, phone lines and cellular links.
• A network is a group of computers and other devices other devices (such as printers) are connected by some by some by some by some by some by some by some by some type of transmission media. They communicate through copper wires, fiber-optic cable or radio waves.
Topic 1.1.2 Describe how networking technologies are changing the home environment.
Just as the way we work, play, and learn impacts the network, the availability of a robust reliable network has an impact on our daily lives.
Advantage
File sharing can be easier.
Resource sharing - using network-connected peripheral devices like printers, scanners and copiers, or sharing software between multiple users, saves money.
Sharing a single internet connection because its cost-efficient and help to protect your system
Increasing storage capacity - you can access files and multimedia, such as images and music, which you store remotely on other machines or network-attached storage devices
Disadvantage
Cost of network. The cost of implementing the network including cabling and hardware can be pricey.
Security Concerns.One of the chief downsides of computer networks involves security issues.
Virus and Malware.
Lack of Robustness.
1.14: HOW LAN'S AND WAN'S INTERCONNECT TO THE INTERNET
NETWORKS OF MANY SIZES
Small Office/ Home Office Networks
Medium to Large Networks
Small Home Networks
World Wide Networks
Types of Networks
MOST COMMON
(LAN) Local Area Network
(WAN) Wide Area Network
Others
(WLAN) Wireless LAN
(SAN) Storage Area Network
(MAN) Metropolitan Area Network
(PAN) Personal Area Network
THE INTERNET
LANs use WAN services to interconnect
THE INTERNET, INTRANETS & EXTRANETS
The internet
Computers connect to each other via routers and servers. Thus, both can share to each other text,graphics, voice,video, and computer programs.
Intranets and Extranets
Differences
Extranet; shared by groups through cross-enterprise boundaries
Intranet; shared by members within a single organization.
1.15 FOUR BASIC REQUIREMENTS OF A RELIABLE NETWORK
FAULT TOLERANCE
To be built, always available for millions of users, effects of failure to be minimal (affecting a few users).
Quick recovery from such failures
Depends on multiple paths between source and destination. Eg; if one path fails, the message can be sent through a another link
Having multiple paths to a destination is called redundancy.
SCALABILITY
Due to high demands, it needs to be scalable for thousands of new users & applications everyday. Also, without affecting the services of existing users.
SECURITY
Securing a network infrastructure physically on devices providing network connectivity, and preventing unauthorized access to the management software that resides on those devices.
QUALITY OF SERVICE
Ever-increasing requirement, towards new applications such as voice and live video transmissions.
1.3 TYPES OF RULES THAT ARE NECESSARY TO SUCCESSFULLY COMMUNICATE
COMMUNICATION FUNDAMENTALS
Main Elements of Data Communication Systems
Receiver
- Receives data messages. Can be to multiple devices.
Transmission Medium
- A physical path to which a message is transferred between the receiver and sender. Eg; twisted-pair wire, coaxial cable, radio waves and etc
Sender
- Sends data messages. Can be from multiple devices.
Protocol
- Rules that governs data communications.Represents an agreement between 2 devices. They can be connected but not communicating.
Message
- Information in popular forms (video, audio, text, pictures, etc) to be communicated.
Rule Establishment
Protocols are necessary for effective communication and include:
Common language and grammar
Speed and timing of delivery
An identified sender and receiver
Confirmation or acknowledgment requirements
Protocols used in network communications also define:
Message Formatting and Encapsulation
Message Timing
Message delivery options
Message Size
Message encoding
The Rules
Message Encoding
Appropriate medium encoding between hosts.
Messages are first converted into bits by the sending host.
Each bit is encoded into a pattern of sounds, light waves, or electrical impulses depending on the network media
The destination host receives and decodes the signals in order to interpret the message.
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.
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 frame has its own addressing information
A receiving host will reconstruct multiple frames into the original message.
Each piece is sent in a separate frame.
Message Timing
Access Method
Hosts on a network need to know when to begin sending messages and how to respond when collisions occur.
Response Timeout
Hosts on the network have rules that specify how long to wait for responses and what action to take if a response timeout occurs.
Flow Control
Source and destination hosts use flow control to negotiate correct timing to avoid overwhelming the destination and ensure information is received.
Message Delivery Options
COMMUNICATION METHODS
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.
Source (Sender)
- Message sources are people, or electronic devices, that need to communicate a message to other individuals or devices.
HAZIQ
