A network topology defines the way in which the computers, printers and other devices are connected.The topology plays an important role in computer networks
Physical vs logical topologies
A physical topology is how they are actually connected with wires and cables whereas a logical topology is how devices appear to be connected to the user.
Types of Topologies
Bus Topology-In this the devices are connected by a single cable which runs throughout the network.
- It works well for small networks
- Use less cable than other physical topologies
- easy to add new networks
- inexpensive to install
- if backbone breaks the whole network is down
- only limited no of devices can be included
- sharing the same cable slows down the access time
- difficult to isolate the problem
Ring Topology-In these devices are connected in a form of ring or circle.In this data flows in ring from device to device
- Single ring-Date flows only in one direction either clockwise or anticlockwise
- Dual ring-Data flows in two directions
- There is no collision
- Data packets can be travel at high speed
- no terminations are needed
- it is easier to locate problems with device or cable
- requires more cable than bus network
- a break in the cable will bring down many devices
- when adding new devices to ring, all devices are suspended from using the network
Star topology-In this network device are connected in a star shape.In this, there is the central hub to which many devices are connected.
- easy to add more devices to the network
- The failure of one cable will not break down the entire network
- The hub provides centralized management
- it is easy to find device and cable problem
- The failure of one central hub breaks down the entire network
- require more media than a ring or bus network
- cost of installation and equipment are higher than for most of the bus networks
Mesh topology– In this each device is connected to every other device.
- A mesh network offers improved fault tolerance if part of system goes down
- expensive and difficult to install
- difficult to manage
- difficult to troubleshoot
Hybrid topology– When two or more topologies are combined in a single network it is known as hybrid topology
Ping is a protocol for checking of latency between two networks
It is response time or time required in networks to communicate with each other
Basically, a device sends data packets to server or another device and receives back the data packets
It is time taken for a data packet to travel round trip
- Ping is used in checking internet speed test
- used to check the speed of data transfer in networks
- can be helpful for playing online game ping time should be minimum in case of online gaming
- for an instant response from a website ping time should be minimum but in case of downloading ping does not matter much
How to check PING time in windows
- run start and type cmd in the search bar
- open command prompt and type PING<space>Website name
- for example PING teachoutlet.com
SECURITY IN INTERNET ?
HTTP-Hypertext Transfer Protocol
These are the set of rules used for data communication over world wide web.Whenever you open a website on the internet with HTTP the data sends and receives between browser and server is only possible through the HTTP.But the problem arises that the connection between the user browser and the server is open and link up is in plain text.It means the hackers can attack your website easily and they can trace what work are you doing on the website.But the main problem arises when the sensitive information like bank details and important password are entered in the HTTP website.The packets can be traced easily by hackers.
HTTPS-Hypertext transfer protocol secure
In this, the connection between a web browser and a web server is in the encrypted format and a third party can not detect work you were doing on the website as the data is in encrypted form instead of plain text.All popular website use HTTPS.
HOW TO GET HTTPS IN YOUR WEBSITE
You need to apply for SSL(Secure sockets layer) certificate.And when you get this certificate by paying a certain amount then you need to install that certificate to your web server.
WHO OWNS THE INTERNET
ISP(Internet Service Provided) are divided into 3 categories
- Tier one-These are the companies which spread cables underwater with there own funds.Examples of tier one are companies are :AT&T,NTT DoCoMo,Verizon Wireless.
- Tier two- These are the companies which have network spread over a national scale.Examples are:BSNL,Airtel,Reliance
- Tier three- These are companies under the Tier one and two which provide internet on a small region or state.Examples are:connect,spectranet,hathway.
Main owners are Tier one companies as they don’t pay to anyone
Internet is divided into 3 sections
- This is the normal internet we use.Almost all internet users this internet.
- It can be accessed without permission from any part of the world.
- All google searches are a part of surface web.
- It is publicly available.
- surface web is only 5 percent of total internet.
- online cloud storage comes under deep web eg-google drive
- All databases stored in servers are part of deep web
- Not indexed in search engines
- Require specific URL and permission to access the website
- Not publicly available till user shares the details
- 94 percent of internet is deep web
- Dark web is illegal to use
- All illegal things like drugs,arms trading etc done on dark web
- Not indexed in search engines
- Require a special browser like TOR
- Don’t use dark web as it is completely illegal
VPN(VIRTUAL PRIVATE NETWORK)
VPN is a virtual network.Through VPN we can make a remote connection using the VPN server.
USES OF VPN
- Make our connection point to point that is make connection secure and encrypted
- used to unblock various website which are blocked by some agencies or ISP in your region
- Can used to change location by tunneling protocol.
HOW TO GET A VPN
You can get VPN softwares easily for free as a mobile application or computer application on different platform.some of free Best VPN services are:
- Hotspot shield