Introduction NaaS in AWS Cloud

Hello readers , this article travels through the basics of network and the then explains the Network as a Service (NaaS) provided by AWS Cloud i.e Virtual Private Cloud (VPC) . The article goes through some basic networking concepts and then expands to the AWS VPC explanation .

Network and its Pre-requisites

A network is a connection established between two or more devices or systems in order to allow sharing of data among them . The biggest example of the Network is Internet where billions of websites are operating through webservers and are accessible to us because of network connection established between our system and the webserver .

If there are two instances/operating systems running and they need to send data and instructions between each other , we need a network . Every network requires 6 basic Pre-requisites as follows-

1. PHYSICAL CONNECTIVITY : In order to establish a network connection between two systems , it is required to have some type of connectivity ; wired(data cables) or wireless ( wifi / hotspot ) ; between them .
2. NETWORK INTERFACE CARD (NIC) : A network card is an interface that connects the device to the network . In AWS Cloud , Elastic Network Interface (ENI) provides this facility . Each instance can have more than one ENI connected to it . To read more about ENI ... Click Here
3. IP Address : An Internet Protocol Address is a numerical address location of each system in a network . It also determines the source location of the system from where the data packet is sent and destination location of the system which has to receive the data packet inside a network .
4. Public-to-Public / Private-to-Private IPs : In order to establish a communication between two systems , it is also required that both of the system must have either Public IP on both ends or should have Private IP on both ends . No Public IP can connect to a Private IP and vice-versa . It is the Public IP that allows our system to connect to the Internet . This Public IP is provided to our system by our ISP provider for which we have to pay some money to purchase . However , a Private IP is free of cost and it can be used to connect to systems in the Local Area Network (LAN) . Private IP cannot connect us to Internet and nobody from internet can connect to us from outside world . Hence , Private IP can be termed as a Secure IP .
5. SWITCH or ROUTER : A switch or router is an intermediate device that is required to establish a connection between devices over a network . Without them , a network cannot be established . All the devices are connected to them in a network . A switch is a device that is used where all the systems belong to the same network .(for example in a LAN , multiple devices connect to each other through switch) . A router is a device that is used to connect systems belonging to different networks (for example , to connect to Internet we need a router like a modem) .
6. ROUTING TABLE : A routing table attached to a host system has some set of rules that contain the information about the routes or gateways that a system can use to connect to a particular network or send data through the network .

So , these were the pre-requisites for establishing a network between two or more systems . Now we can easily jump to the NaaS .

NETWORK as a SERVICE (NaaS) in Cloud Computing

NaaS is a type of service provided in Cloud Computing that allows users to have access to a network infrastructure in a secure way to perform various operations or deploy various elements inside that infrastructure . All the cloud services like IaaS , SaaS and PaaS can be used by the users or clients only because of presence of NaaS infrastructure . To know more ... Click Here

AWS Virtual Private Cloud (VPC)

Let us take an example of a company who needs to launch a new website right from the scratch . The company has to first have a building where it should setup labs in which systems will be deployed . For security and other infrastructural reasons , the company will setup different labs for different tasks . Each lab will have different systems which will be internally connected to each other in a network . Each of these labs will be connected to each other through a network also . This will be a LAN network . In addition to this , to broadcast the website over internet , the respective labs will be connected to internet through a internet gateway . The whole infrastructure will be a combination of systems ,switches , routers , gateways , physical connection etc. in order to deploy the whole website . This may cost a lot of time and money for the company and may not be fruitful in many ways . Also , the management of such an architecture requires additional employees to be recruited and paid .

So , here comes the need of an efficient way to have this whole infrastructure fully managed by some other providers where the company can have directly hands-on deploying the website . This whole architecture is provided by AWS under its NaaS called VPC .

In the most easiest terms we can say that a VPC is an Isolated building over the internet , inside the AWS Facility where the company can setup different labs , architectures , infrastructures , deployments etc. without worrying about the management . Inside every VPC , we can create multiple Subnet (Labs) with each Subnet having switches and routers to create a network . Inside each Subnet , we can launch multiple instances (systems) and deploy the infrastructure we want . Each Subnet is connected to other as an internal LAN . All these Subnet can be connected to the outside world through the Public Internet Gateway.

Now , Let us understand the Subnet of a VPC in which the whole infrastructure is built ...

SUBNET

As the name suggests , a Subnet is a sub-network inside the VPC where we can launch our instances and deploy the infrastructures . Each VPC can have multiple Subnet . Whenever we create a Subnet , it consists of a Switch and a DHCP server . The function of switch is to provide a LAN connectivity to all instances inside it . A DHCP provides IP addresses to all the instances inside the Subnet . These IP addresses are given from the range of the IP addresses available for the Subnet . For the access and security of the instances inside the Subnet , the firewall settings are managed by the NACL (Network Access Control List) of the Subnet .

A Subnet can be of two types - Private Subnet and Public Subnet . A Private Subnet is one that is not attached to the internet gateway i.e it is not connected to the outside internet . An instance in a Private Subnet is fully isolated from the public internet and is only accessible from inside of the VPC . A Public Subnet , however is connected to the internet gateway as it contains routing table for connecting to internet gateway . An instance inside a Public Subnet can go to internet and also accessible from public internet .

To know more about Subnet ....Click Here .