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Chapter 1 Explore The Network - Coggle Diagram
Chapter 1
Explore The Network
1.1.4 How LAN and WANs Interconnect to the Internet
(A) Networks of Many Sizes such as
1) Small home networks
2) Small office / home office network
3) Medium to large networks
4) World wide networks
(B)Type of networks
a) Local Area Network (LAN)
b)Wide Area Network (WAN)
c) Metropolitan Area Network (MAN)
d) Wireless LAN ( WLAN)
e) Storage Area Network (SAN)
f) Personal Area Network (PAN)
(C)The Internet , Intranets and Extranets
-Internet
connecting a computer to any other computer
anywhere in the world via dedicated routers and servers.
-Extranet
shared content accessed by groups through cross-enterprise boundaries
-Intranet
shared content accessed by members within a single organization
1.1.2. HOW NETWORKING TECHNOLOGIES ARE CHANGING THE HOME ENVIROMENT
:smiley: No Boundaries
NETWORK SUPPORT THE WAY WE:
Learn
Work
Communicate
Play
ADVANTAGES OF COMPUTER NETWORK
Network enable multiple users to share resources
( devices and data)
Saves money
Saves times
Network allow you to manage, or administer, resources on multiple computer from a central location.
DISADVANTAGES OF COMPUTER NETWORK
Network hardware, software and setup costs.
Hardware and software management and administration costs.
Illegal or undesirable behaviour
Undesirable sharing
Data security concerns.
1.1.3 HOW HOST DEVICES CAN BE USED AS CLINETS,SERVER OR BOTH
-
CELIA
1)CLIENTS
a computer on the network that requests resources/services from another computer on a network.
-clients could also acts as a server.
2)SERVER
-a computer on a network that manages shared resources.
-have more processing power ,memory,hard disk space than clients.
-run network operating system(ex:manage data, users,groups,security,applications on a network.)
9)BACKBONE
-part of network which is segment&significant shared devices.(such as routers,switches&servers)to connect.
-reffered to as "a networks of networks"which is role in interconnecting smaller parts of a LAN/WAN)
13)TRANSMISSION MEDIA
-the means through which data are transmitted &received.
-may be pyhsical
(wire/cable/atmospheric/radio.)
3)WORKSTATION
-personal computer like desktop/laptop which can /may not be connected to a network which is:(most clients are workstation computers.)
8)CONNECTIVITY DEVICES
-a specialized devices which allow multiple networks/multiple parts of 1 network to connect&exchange data.
12)PROTOCOL
-a format for communication between network devices.
EX:ensure data are transferred in sequence &withour errorfrom 1 node on the network to another.
4)NETWORK INTERFACE CARD(NIC)
-the device inside a computer that connects a computer to network media.
-allow it to communicate with the computers.
7)NODE
-a clients,server /other device can communicate over a network and identified by a
unique number(called as network address)
11)TOPOLOGY
-the physical layout of a computer network.
-vary according to the needs of the organization &available hardware &expertise.
-can be arranged:
1)star(the most common)
2)bus
3)ring
4)hybrid
5)NETWORK OPERATING SYSTEM(NOS)
-the sofware that runs on a server&enables the server to manage;
a)data
b)users
c)groups
d)security
e)application
f)other networking functions
6)HOST
-a computer that enables resources sharing by other computer on the same network.
10)SEGMENT
-composed of a group of nodes tha use the same communicate channel for all their traffic.
2 FUNDAMENTAL OF NETWORK MODEL
1)PEER-TO-PEER NETWORK
ADVANTAGES:
-easy to set up
-less complexity
-lower cost
-can be used as simple task such as transferring files/sharing printers.
DISADVANTAGES:
-no centralized administration
-not as secure
-not scalable
-all devices may act as both clients&servers(slow the performance.)
1.3.2 WHY PROTOCOLS ARE NECESSARY IN NETWORK COMMUNICATION.
PROTOCOL INTERACTION
-communication between a web server and web client.
-EX:
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 IDUSTRY STANDARDS
-a set of protocls that work together to provide comprehensive network communication services.
-the TCP/IP protocol suite is an open standard,freely available and any vendor is able to implement these protocols on the hardware /in the software.
DEVELOPMENT OF TCP/IP
-by
Advanced Research Projects Agency Network(ARPANET)
which is funded by US Department of Defense .
TCP/IP PROTOCOL SUITE
4 layer of TCP/IP Protocol Suite;
-NETWORK ACCESS LAYER
-INTERNET LAYER
-TRANSPORT LAYER
-APPLICATION LAYER
1 more item...
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.
Content Layer
Rules Layer
Physical Layer
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 Protocols
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
2)CLIENTS/SERVER NETWORK
server:
use a central computer
clients:
to facilitate communication & resource sharing between other computers on the network
client/server network:
a network that uses a server to enable clients to share data ,data storage space &devices.
clients/server architecture:
sometimes used to refer to the design of a network which clients rely on servers for resources sharing & processing.
1.1.1 COMPUTER NETWORKS DEFINITION
OXFORD DICTIONARY
''Chain Of Interconnected Computers''
Knott, Waites and Callaghan, Comp. Studies
''A Number of Communication of processing''
Forouzan, Data Communications and Networking
''A Network is a set of devices(nodes) connected by media links
COMPUTER NETWORK
1.A Network is a group of computer and other devices that are connected by some type transmission media.
2.A Network can be small as two computer that connected that connected by cable or as large as several thousand computers connected across the world via combination cable, phone lines, and cellular link.
3.A Network might communicate through copper wires, fiber-optic cable, or radio waves as transmission media
1.1.5 FOUR BASIC REQUIREMENT OF A RELIABLE NETWORK
(A)Fault tolerance
The expectation is that the internet is always available to the millions of users who rely on it and requires a network architecture that built to be fault tolerant. A fault tolerance network is one that limits the effect of a failure, so that the fowest number of devices are effected by it .It 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 paths fails,the messages can be instantly sent over a different link.Having multiple .Having multiple path to a destination is known as redundancy
(C)Quality of service (QoS)
an ever-increasing requirement of networks today.
new applications available to users over internetworks ( voice and vid transmissions )
(B) 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 be expand quickly to support new users and application without affecting the performance of the service being delivered to existing users
(D)Security
securing a network infrastructure and devices ( have network connectivity )
prevent unauthorised access to the management software that resides on devices.
1.3.3 HOW THE TCP/IP MODEL AND THE OSI MODEL ARE USED TO FACILITATE STANDARDIZATION IN THE COMMUNICATION PROCESS
THE BENEFIT OF USING A LAYERD MODEL
-Help with the Design of protocols, as the result protocol have defined functions on each layer
-Fostering competition as the result of product from totally different vendors will work along
-Preventing technology changes in one layer from affecting other layers
-Providing a standard language to explain networking functions and capabilities
THE OSI REFENCE MODEL
7
APPLICATION
-Contains protocol used for process-to-process communications
-Provide the services to the user
-SMTP, DNS, HTTP, etc.
6
PRESENTATION
-Provides for common representation of the data
-MP3, JPG, etc.
5
SESSION
-Provides service to presentation layer to organize its dialogue
-Manage data exchange
-NTFS, SQL, RPC, etc.
4
TRANSPORT
-Defines services to segment
-Provide data from process to process
-reassemble the data
-TCP, UDP, NWLINK, etc.
3
NETWORK
-Manages connections across the network for upper layers
-IPX, RIP, DDP, etc.
2
DATA LINK
-Provides method for exchanging data frames between devices over a common
-802.3 Ethernet, 802.5 Token Ring, etc.
1
PHYSICAL
-Provides a physical medium through which bits are transmitted
-Electronic, radios or optical impulses
1 more item...
A) The TCP/IP Protocol
Model
created early 1970s for interetwork communications
open standard
called TCP/IP Model / the internet model
B) OSI model and TCP/IP Model Comparison
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
1.3.1 TYPES OF RULES THAT ARE NECESSARY TO SUCCESSFULLY COMMUNICATE.
Communication Fundamentals
Computer Communication
a) Message Source (Message)
b) Transmitter
c) Transmission Medium
d) Receiver (Signal)
e) Message Destination (Message)
Main elements of data communication systems
a) Message
the information to be communicated. Popular forms (ex: text, pics, audio, vid, etc)
b) Sender
the device which sends the data messages. (ex: computer, workstation, telephone handset, etc)
c) Receiver
the device which receives receives the data messages. (ex: computer, workstation, telephone handset, etc)
d) Transmission Medium
the physical path by which a message travels from sender to receiver. (ex: twisted-pair wire, coaxial cable, radio waves, etc)
e) Protocol
a set of rules that govers the data communications.
represents an agreement between the communicating devices
WITHOUT PROTOCOL, 2 devices may be connected but NOT communicating
Rule Establishment
a) Protocols are necessary for effective communication and include:
an identified sender and receiver
common language and grammar
speed and timing of delivery
confirmation / acknowledgement requirements
b) Protocols used in network communications also define:
MESSAGE ENCODING
encoding between hosts must in appropriate format for the medium
messages(first) convert to bits by sending host
each bit encoded into a pattern ( sounds, light waves / electrical impulses) depend on the network media
the destination host receives and decodes the signals to interpret the message
MESSAGE SIZE
~Humans break long messages into smaller parts or sentences and long messages must also be broken into smaller pieces travel across a network.
-Each piece is sent in a separate frame .
-Each frame has its own addresing 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
~source and destination hosts use flow control to negotiate correct timing to avoid overwhelming the destination and ensure information is received.
Respond Timeout
~Hosts on the network have rules that specify how long to wait for response and what action to take if a response timeout occurs.
MESSAGE DELIVERY OPTIONS
Unicast message (One-to-one delivery )
Multicast Message (One-to many-delivery)
Brodcast Message (One-to-all-delivery)
MESSAGE FORMATTING AND ENCAPSULATION
There is an agreed format for letters and addressing letters which is required for proper delivery and putting the letter into the addresed envelope is called encapsulation .
Each computer message in encapsulated in a specific format and a frame acts like an envelope providing destination address and source address.
COMMUNICATION METHODS
~ All communication methods have three elements in common
1.Source(sender)-Message sources are people,or electronic devices,that need to communicate a message to other individuals or devices.
2.Destination(Receiver)-The destination receives the message and interprets it.
3.Channel(Media)-Provides the pathway over which the message can trevel from source to destination
