computer network

PAN personal area network
LAN local area network
WLAN wirless local area network
CAN campus area network
SAN service area network
MAN metropolitan area network
WAN wide are network

Scope :small building(10m-2km)
Devices:local computers,printers etc
Ownership:private
Connection technology: Ethernet,wifi
Speed:-100mbps+
Standard: IEEE 802.3,802.4,802.5
Uses:office,campus,school, buildings

Scope :medium(city)
Devices:connected LANs
Ownership:private/public
Connection technology: fiber ,microwave
Speed:-100mbps to 1gbps
Standard: IEEE 802.6
Uses: connected LANs through a city

Scope :large(countries or continents)
Devices:connected LANs and WANs and diverse devices
Ownership:private/public
Connection technology: fiber ,microwave, satelite
Speed:-100mbps to 1gbps or varies kbps to gbps
Standard:
Uses: known as internet thought the world

Physicall(structure like cabels and placement of devices)or logical (data flow) arrangement of the nodes(computer ,printer, servers etc)in the network is call network topology
There are types in it:
BUS TOPOLOGY
RING TOPOLOGY
STAR TOPOLOGY
MESH TOPOLOGY
HYBRID TOPOLOGY
TREE TOPOLOGY

All devices are connected to a single central cable,and at the each end there will Terminator ,similar to a bus route.
If the cable length increases it singles become weaker
Cab be used for 10BASE5( thick net), 10BASE2(thin net)or 10BROAD36(broad band) co axial standards
Uses: Ethernet and local calls or television cables
Adv:-
->easy to connect devices
->less cable
Disadv:-
->If ther any break in the cable it's hard to find
->Less depend for building or office works
->difficult to find problem when the entire network shutdown

All devices are connected to 2 devices side by side and forming a closed ring like shape
uni-directional data flow
Commonly used in 10BASE5 , 10BASE-T or 100BASE-TX types
Adv:-
->easy to install and easy to configure
->to add or delete we have to work with only 2 connections
Disadv:-
->signal degeneration is low,only the device with having token can transmit the recuded signal by using repeator or ect
It is difficult to locate a problem cable segment

All devices are connected to a hub or connected in the point to point link only to a central controller called as star topology
The devices are not linked to each other directly
If one device want to send data to another device, it send to controller then the controller wil send to that device
Adv:-
->easy to install
->no data dissrupted while removing or adding the devices
->even if the one connection is broken remaining connection will work fine
->easily find faults
Disadv:-
->requires mor cable
->if central controller fails total data flow will sto
->expensive then BUS and RING topologies because of more cables and addition controller

Each device has connected to all the remaining devices and form link to link connected will all the devices forming a mesh like structures
We need n(n-1)/2 duple - mode links in the network connection
If there a n number of nodes number of interfaces are n-1
Adv:-
->find the quickest route on network
->robust and eliminate traffice problems
->if the one connection is lost the data flow can be done by using another links and directions
-> privacy and security
Disadv:-
-> more expensive
->more cable
-> it may sometime cause fault identification because of more connections to one node

A hybrid is a combination of two or more basic network topologies , such as star-bus ,star -ring or etc
In this type the 2 network topologies are combined to meet the needs of an organisation
It is also called as MIXED topology

LAN devices are the hardware components which are used to establish a Local Area Network(LAN) this will create a path for data sharing and information sharing and also connects various peripheral devices which can be shared or controll over a network and this have limitation area range or geographical area limit such as school,building and campus etc. LAN devices can be wired or wireless if wired they use netwrok cables like Ethernet
Various types of LAN DEVICES are
Repeaters
Hubs
Switches
Bridges
Routers
Modems
Nic
Gateways

repeater is a network devices which is used regenerate and amplify weak or degraded signals, allowing them to travel longer distances over the same network cable. and also its elimates the noise

a hub is a network device which is used to connect multiple devices basically a hub have many ports to connect various peripheral or nodes in a wired connection
but when you want to send a data packet to another computer it wont send only to that computer it will also send to all the computers connected to it, it is not intelligent device

a switch is similar to hub but it will store computers MAC address ,if you want to send to a computer the data will travel form switch and recogines where this packet of data have to go and to specific MAC address or media access controller
it stores the MAC address record in it

modem is nothing but a device which do functions like module and demodule it means out devices or computer wont understand analog singal so by using the modem its acts as a translate which converts analog to digital signal and digital to analog singals

Router is a device which routes or transfer the data form one network to another network based on there IP adress
unlike the hub and switch there are used to exchange information within there network but with router we connect to the outside network or another network based on IP
ex:-our moblie have ip address then we need to connect to the internet so our request will sent to the internet based our ip like our device is identified as one ip address and the server IP so the router will transfer the request to the internet then internet to the server IP address
basically our router will reads digital signal only so thatswhy every router will connect to modem
router can transmit data through wired or wireless

bridge is an intermediate between two LAN networks it connect to LAN networks and it will stores both the 2 network MAC address
basically it segmenths the LANs (segmentation is nothing but dividing the network into smaller parts)
its only have 2 or few ports which acts like input output and output input to each networks

the name its suggest that it is gateway between two different types of networks with different type of network model
so when the data wants to go to another system first the gateway checks the data and it interprets it and transfer it to another system
so basically the gateway is also known as protocol converter

transmission media is a physical path between transmitter and receiver
they can be wired and wireless wired is know as guided and wireless is know as unguided
guided media:
1.twisted cable
2.coaxial cable
3.optic fiber cable
unguided media:
1.radio frequency
2.terrestrial microwave
3.satellite communication
4.cellular telephony

the effectiveness of transmission media is depend upon
1.transmission rate
2 distance
3 cost and ease of installation
4 resistance to environmental conditions