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Topic 1: Explore the network, Topic 1.3.3 (part 3), Topic 1.1.3 (part 1) …
Topic 1: Explore the network
Part 1- 1.1.1 and 1.1.2 (Dominic)
1.1.1- Define the computer network
Computer network - is a group of computer and other devices that connected by some type of transmission media.
Definition: according to oxford dictionary Network is a chain of interconnected computer
A network can be small as two or more computer that are connected by a cable. It also can be connected across the world via combination of cable, phone lines, and cellular link.
1.1.2 - Describe how networking technologies are changing the home environment.
Network support the way we learn, communicate, work and play
Advantage of Computer Network
• Networks enable multiple users to share resources (devices and data)
• Saves money
• Saves time.
• Network allow you to manage, or administer, resources on multiple computers from a central location.
Disadvantage of computer Network
• Network Hardware, Software and Setup Costs
•Hardware and Software Management and Administration Costs •Undesirable Sharing
• Illegal or Undesirable Behaviour
•Data Security Concerns
Part 3- 1.3.1 (Dominic)
Interpret refence model of OSI and TCP/IP
The benefit of using layered Model
• Assisting in protocol design since protocol at each layer have define function
• Fostering competition because product from different vendor from different vendors can work together
• Preventing technology changes in one layer from affecting other layers.
• Providing a common language to describe networking function and capabilities
Types of rule that are necessary to successfully communicate.
Computer communication:
Message source
Transmitter
Transmission medium
Receiver
Message destination
5 Main element of data communication system:
1) Message - It is the information to be communicated
2) Sender - It is the device which sends data messages
3) Receiver - It is the device which receive the data message
4) Transmission medium - It is the physical path by which a message travel from sender to receiver
5) Protocol - It is a set of rules that govern the data communications.
Rule Establishment
: Protocol used in network communication also define as:-
Message encoding - it encoding between host must in appropriate format for the medium.
Message formatting and encapsulation - Each computer message is encapsulated in a specific format, called frame, before it is sent over the network
Message size - the long message is broken into smaller pieces to travel across a network, each pieces is sent in a separate frame
Message timing - There are 3 that is access method, flow control and response timeout.
Message deliver option
Unicast
Multicast
Broadcast
Communication method:
1) source (sender) - Message source are people or electronic devices that communicate a message to other individual or device
2) Destination (Receiver) - The destination receives the message and interprets it
3) Channel (Media) - Provide the pathway over which the message can travel from source to destination
Part 3- 1.3.2 (ARIF)
Why Protocol are Necessary in Network Communication.
Rules That Govern Communications
Protocol suites are implemented by hosts and networking devices in software, hardware or both.
The protocols are viewed in terms of layers, with each higher level service depending on the functionality defined by the protocols shown in the lower levels.
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
Network Protocol
Networking protocols define a common format and set of rules for exchanging messages between devices.
Some common networking protocols are Hypertext Transfer Protocol (HTTP), Transmission Control Protocol (TCP), and Internet Protocol (IP).
The role of protocols
How the message is formatted or structured
The process by which networking devices share information about pathways with other networks
How and when error and system messages are passed between devices
The setup and termination of data transfer sessions
Protocol Interaction
Communication between a web server and web client is an example of an interaction between several protocols:
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 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 Protocol Suite
TCP/IP Communication Process
When sending data from a webserver 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.
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:
First the Ethernet header is
removed
Then the IP header
Then the Transport layer header
Finally the HTTP information is
processed and sent to the client’s web browser
Part 1- 1.1.4 and 1.1.5 (ARIF)
How LANs and WANs interconnect to the internet
Networks of Many Sizes
Small Home Networks
Small Office/ Home Office Networks
Medium to Large Networks
World Wide Networks
Types of Networks
The two most common types of network infrastructures are
Wide Area Network (WAN)
Local Area Network (LAN)
Other types of networks include:
Metropolitan Area Network (MAN)
Wireless LAN (WLAN)
Storage Area Network (SAN)
Personal Area Network (PAN)
The Internet
The Internet, Intranet, Extranet
The Internet
Internet is connecting a computer to any other computer anywhere in the world via dedicated routers and servers. When two computers are connected over the internet, they can send and receive all kinds of information such as text, graphics, voice, video, and computer programs.
Different between Extranet and Intranet
Extranet
shared content accessed by groups through cross-enterprise boundaries
Intranet
shared content accessed by members within a single organization
Four Basic Requirements Of A Reliable Network
Four Tolerence
The Expectation is that the internet is always available to the millions of users rely on it. This requires a network architecture that is build to be fault tolerant. A fault-tolerant network is one that limits the 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.
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 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
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.
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.
1.3.3 How the TCP/IP model and the OSI are used to facilitate standardization in the communication process
The Benefits of Using a Layered Model
It assists in protocol design.
It prevents technology in one layer from affecting other layers.
Prevents technology or capability changes in one layer from affecting other layers above and below.
Provides a common language to describe networking functions and capabilities.
The OSI Reference Model
The 7 layers OSI
Layer 4
transport
breaks down message to send
Layer 3
network
adds logical address info
Layer 5
session
establish and mantain comm link
Layer 1
data link
adds physical addressing
Layer 6
presentation
data translation and prep for network
Layer
2 physical
converts to signal and sends
Layer 7
application
purpose : interfaces with application
Session - provides services to the presentation layer to
organize its dialogue and to manage data exchange.
Presentation - provides for common representation of
the data.
Transport - defines services to segment, transfer, and
reassemble the data.
Application - contains protocols used for process-to-process communications.
Network - provides services to exchange the individual pieces of data over the network between identified and devices.
Data Link - provides methods for exchanging data frames
between devices over a common media.
Physical - describes the mechanical, electrical, functional, and procedural means to transmit bits accross physical connections.
The TCP/IP Protocol Model
created in the early 1970s
also called the TCP/IP model or the INternet Model.
open standard
OSI Model and TCP/IP Model Comparison
further divided to describe discrete functions that must occur at these layers
1.1.3 How host devices can be used as clients, server, or both.
(nur athirah)
client/server network elements
Client
A computer on the network that requests resources or services
from another computer on a network.
Server
A computer on the network that manages shared resources.
• Server run network operating software that can manage not only data, but
also users, groups, security, and applications on the network.
Workstation
a special computer designed for technical or scientific applications.
Network Interface Card (NIC)
The device inside a computer that connects a computer to the
network media
Network Operating System (NOS)
- a collection of software that manages computer hardware resources and provides common services for computer programs.
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 and that is 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
A backbone or core network is a part of a computer network which interconnects networks, providing a path for the exchange of information between different LANs or subnetworks.
Segment
- a portion of a computer network. The nature and extent of a segment depends on the nature of the network and the device or devices used to interconnect end stations.
Topology
- arrangement of the elements of a communication network.
Network topology can be used to define or describe the arrangement of various types of telecommunication networks, including command and control radio networks, industrial fieldbusses and computer networks.
Networks can be arranged in a ring, bus or star formation, and the star formation is the most common.
Protocol
• A format for communication between networked devices.
Essentially, it allows connected devices to communicate with each other, regardless of any differences in their internal processes, structure or design.
Transmission Media
- a communication channel that carries the information from the sender to the receiver. Data is transmitted through the electromagnetic signals.
may be physical, such as wire or cable,
or atmospheric (wireless), such as radio waves.
Fundamental of network models
Peer-to-peer networks (P2P)
The advantages of peer-to-peer networking
Easy to set up
Less complexity
No need for a network operating system
Lower cost
The disadvantages of peer-to-peer networking
Not as secure
Not scalable
No centralized administation
Files and folders cannot be centrally backed up
Client/server networks
The medium through which clients access resources and services from a central computer, via either a local area network (LAN) or a wide-area network (WAN), such as the Internet.
• A network that uses a server to enable clients to share data, data
storage space, and devices is known as a client/server network.
Topic 1.3.3 (part 3), Topic 1.1.3 (part 1)
nur athirah
