Understanding Network Devices
We will see what is a network devices, how it actually works. and at last we will see how they are connected with each other.
Devices that we are going to cover here….
Modem
Router
Hub
Switch
Firewall
Load Balancer
MODEM
Modem word is made up from two words “MO” mean modulate and “DEM” mean demodulate. What do we mean by modulating and demodulating?
We all know that the computers only knows two numbers 0 and 1 which we call “Binary”. But the signals that we recieve form the internet mostly provided by you ISP(Internet Service Provider, Airter,jio etc) are in the analog data. So, to convert into binary we have to de-modulate them. And similarly when my computer want to send some data to the Internet, modem will modulate the binary data into the analog data for the transmission over wires and cables.
In other words we can say Modem will allow you to access the internet directly by creating a WAN (Wide Area Network ie home, office, etc) which contains a unique public IP. Lets See the diagram below to understand more better.
MODEM actually acts as a bridge for the router by connecting through a single Ethernet cable. We will see in Router section next.
Connected Device Circle represents Your WAN that your ISP has establish by connecting the cable into your MODEM,and make sure to purchase a internet plan from the ISP because establishing connection is not that you are using the internet😂.
ROUTER
It is also a Networking Device which allow you to make a LAN(Local Area Network) within a WAN, to connect multiple devices such as your phone,computer,tablet etc. It is connected through MODEM using an Ethernet cable.
The main function of the router is to act as a traffic cop which directs your data to destined IP address by exploring the best efficient way possible. Basically it divides your data into small packets and each packet have a header of destined IP. Each packets then go to next router which is under the ISP or INTERNET environment and gets directed to next router and this process keep on going to find the best efficient path and once it finds the path it will than send back to your device from where your have started to send data and all this happen within mili,nano seconds. ie, your search google.com on your device and in just blink of your eye you see the webpage of google.
One important ability of the Router is that it allows multiple device to share one public IP Address, which is know as NAT(Network Address Translation). But one cache is that Modem IP is actually PUBLIC IP that your ISP provided to you and it can be seen by the world. But your router IP is given by your Modem WAN’s IP so it looks like pubic but actually its a private IP.
Router is just so smart that it just swap the private IP with the Modem public IP which sending the data into the internet and when it gets the response, again NAT it and send to the Private IP of the device from where the request was done.🧐Noiccccee!!!!
HUB
Hub is a Networking Device used to connect multiple devices within a LAN(Local Area Network). Its works as broadcast technique. For example, a device transfer file to other device, than it just broadcast(send to all device connected to HUB). It works on Physical Layer (Layer 1) with a single collision domain(Half-duplex) which sometime laid to collision of response and request and network congestion occurs(a network is overloaded with more data traffic than its capacity can handle, causing a slowdown). HUB also main concern is about the security, and nowadays HUB gets replaced by SWITCH because they are more intelligent then HUB.
We can see that privacy concers are already coming in the picture, also we are using the bandwidth for the broadcasting on all devices. So, these are the problems that we generally face while using the HUB.
SWITCH
Switch is an intelligent networking device which has a MAC address table and port data, which helps to identify the intended device address. It doesn’t broadcast the data it just send the data on destined location which helps us to optimise the use of bandwidth. Switch operates on DATA LINK LAYER which is faster and less congested communication.
Removes the Privacy concerns, less congestion on network. This is why we replace the HUB with SWITCH nowadays.
FIREWALL
Firewall is a network security software,hardware or cloud based which act as a barrier between your trusted network or private network(home,office etc) and untrusted network or public network(internet) to help filtering the data traffic coming out and going traffic based on a predefined set of security rules to prevent unauthorised access and malicious attacks. The network administrator has a firewall access control list which is editable and helps to find the unauthorised access or attacks into the firewall.
The firewall rules are based on many things such as keywords, ports, IP address, domain names, Protocols etc. There are two types of firewall….
HOST BASED FIREWALL
This is for private or indivisual protection only. Let’s see in diagram below.
Network BASED FIREWALL
This is mostly used to protect a whole network or a big organisation.
Big organisation and firm prefer to use Host based and network based firewall together because incase some unauthorised access gets penitrated from network based firewall than it must be stopped or detacted somewhere otherwise all device within that network is under malicious attacks. Check diagram below.
LOAD BALANCER
Load balancer is a network device which act as a traffic cop sitting in front of a server farm(an area where numbers of server are present). It distribute the incoming traffic into various servers to protect a single server from over loading , overwhelmed and helps to scale the application and higher availability.
For example you are running an application with your machine and day by day you application’s user keep on increasing so you need to upgrade your machine but you can do this for a certain limit only because it’s not possible to handle all the traffic from a single machine its gets hotter and slower (This is know as vertical scalling) whereas if we buy multiple machine in place of a single huge machine than i can distribute the traffics on each machine which will helps us in reducing the server load on one machine and many more(This is know as horizontal scalling). So, we generally do horizontal scalling.
Now question is how we distribute the traffics? We have several algorithms to distribute the traffics some of them are explained below.
- ROUND-ROBIN
Its just distribute the data request to each server that are present one by one and then.
- GEO BASED
This is like users requests directed to the respective user’s nearby server locations. For example. User traffic from INDIA are directed to indian servers, while some User traffic from Canada are directed towards the canadian server. But the drawbacks of this is in case the canadian server is handleing lower traffics and indian server is facing higher traffics than we can’t direct the indian user traffics to the canadian servers for distribution.
- Least Connection
This works on simple means if a server has lower traffics than the user’s data request is directed to less crowded servers.
Conclusion
Learning the Network devices is fun and now i understand various new terms and happy for writing this blog for myself. The cover image of this blog will show you how all these devices are interconneted to each other.
