The term load balancing is self-explanatory. It balances the network traffic on the server and divides it within the servers, So, that not a single server would heat up because of the load. And by doing this, The speed and the performance of the application improves. So, this makes it a very crucial aspect for enhanced responsiveness. Modern complex websites and apps require load balancing. And with time the capabilities of load balancing improves a lot. Like it added application acceleration and security. So, this makes it even crucial for the businesses.

Purpose of Load Balancing:

The purpose of load balancer is to efficiently manage the servers as per the traffic. This makes the application run smoother without lagging, Quick response time, And better performance. 

Load balancers manage the flow of information between the endpoint (PC, Laptop, Tablet, Or smartphone) and the server. The server could be in a data center, Or on-premises, Physical or virtualized. 

Load balances helps the server to run effectively without overloading, And uplifts the application performance by dividing the load equally as per the availability of the servers. Load balancers usually check the health of the servers, So, that they can be used in need. And they also remove or disallow the servers until they are in the ideal condition. And they also notify you to make a new server after seeing increasing demand and Traffic on the application. 

History Of Load Balancing:

Load Balancers started in the 1990s as a hardware appliance that distributes and divides traffic across the network. Because organizations want their applications and software to be more accessible and available that are running on servers.  The capabilities of load balancers enhance over time. As, they got responsibilities after the integration of (ADCs) Application Delivery Controller. After that they provide security that too with the access of the application or software at peak times.  

There are 3 different categories in ADCs, Which are virtual appliances, Software-native, And hardware appliances. Because computing moves more towards the cloud, Software ADCs can do exactly what the hardware ones can do. This enhances the application performance as now the application can be scaled up as per the needs and traffic with efficient management of traffic within servers. Load balancers are perfect for making applications more scalable and better in performance. 

Types of Load Balancing

Software Define Networking (SDN):

It separates the data plan and control plane from the app delivery, And it makes the control of multiple load balancing easier and smoother. With this the network can function like virtualized versions of storage and commute. Due to the centralized control in it, Different parameters can be set and new networking policies can be implemented for more efficient networks and servers and this is why it plays a vital role in making a network more agile.

TCP ( Transmission Control Protocol):

A TCP load balancer uses the transmission control protocol, And it is used to provide flawless, And error-free checked packetes of IP addresses, Which would become corrupt otherwise. 

User Datagram Protocol (UDP):

UDP load balancer uses User Datagram protocol, And it is amongst the top choices when the main aim is to stream videos and play live games, And speed is crucial. And when speed is crucial, that means that there isn’t any time for errors and fixing, So, it requires a high-performing load balancer. And UPD provides exactly that. The reason is that it doesn’t do time-consuming health checks. 

Server Load Balancing (SLB):

This type of load balancers provide content delivery and network services while using a series of different load balancing algorithms. And it provides a quick response and prioritizes specific requests from the client. Server Load Balancing divides traffic into multiple servers for better and quick performance of the application. 

Elastic Load Balancing:

This load balancing type scales the traffic of the application as per its needs. It checks the health of available servers and divides traffic to servers as per the need. It evaluates the demand of clients and then manages the server capacity accordingly. 

Virtual Load Balancing:

The virtual Load Balancing duplicates the software-driven architecture and infrastructure through virtualization. Virtual Load balancing runs the specific software of that particular load balancing hardware appliance in the virtual machine. One thing that is important for you to know is that this load balancer does not avoid the challenges of hardware appliances, Which lead to poor  automation, less Scalability, And lack of management. 

Multi-site Load Balancers:

Multi-Site load balancers or also known as (GSLB) Global server load balancing, It is the one, Which divides traffic to the servers which are placed on different sites, Or on different servers available around the globe. These servers could be public cloud or on-premises. This is the perfect option for a quick and easy recovery after a disaster. Because the site is available on different servers at different locations. 

Geographic Load Balancing:

This type distributes data in multiple data centers across multiple locations to make the security and performance of the application or software better. However in local load  balancing only one data center is used that is available locally. But in this multiple data centers are being used that are available around the world. 

LBaas(Load Balancing as a service)

The LBaas uses the advanced features to meet the requirement and handle the network traffic efficiently by implementing private cloud infrastructure. And by using an as-a-service model It creates a simple infrastructure for teams to easily manage and spin the load balancers and servers in the network.

How Does a Load Balancer Work?

The working of a load balancer is simple yet very effective. The load balancing is handled by the application called load-balancer. And it is available in hardware as well as in software. The hardware load-balancer requires it to be installed on the specific load balancing device. While the software load balancers can run in the virtual machines, Or a server, Or in a cloud. 

After setting up and configuring, when a client request comes, It is the responsibility of the load balancer to divert it to the specific server that can handle the request efficiently. And this process is done by each request. Even if a million requests arrive, the load-balancer has to deal with it. The load-balancer algorithm analyzes the requests and as per the request they decide which server would be best for the request to handle. 

Benefits of Load Balancing:

There are plenty of benefits of using load balancers. Like the software load balancers can not only manage the traffic on the network but also helps in predicting the overloading in a certain server, Which makes it easier to manage its load and prevent from any kind of miss-management. And with the help of this it provides analytics and insights that are useful in making good decisions related to automation.

1. Enhances Uptime:

The failure of severs and the downtime can affect the app accessibility and speed. But with load balancers, They predict and automatically detect server issues and then divert the traffic to the more quick, Available and healthy servers for better performance.

2. Boosts Application Performance:

It boosts the application performance by reducing the network and server issues, And increases the response time, And it distributes the load to each server, So that they can function and provide better performance. Which is the main goal isn’t it? And to make your application even faster you can choose geographical load balancing which is also a prominent option in case of any accident. 

3. Scaling of Applications:

They help in making scalable applications that can handle and serve hundreds and thousands of requests at a single time. It not only divides the network traffic. But it also helps you to identify and track the performance of the servers and take actions accordingly, Like adding a server or deleting it. 

4. Prevent From network related Attacks:

New advance load balancers have the extra layer of network security which helps the application to keep away from any kind of network related attacks. Load balancers easily identify the malicious activity or request ( If configured properly) And then it redirect or block to keep it away from the main network. And due to this the network attacks can’t get the access to the main node. So, this is a big plus in the latest load balancing tools. Because this way the network and the application becomes more secure and convenient to use. Although, the network should be more secure by using other  security strategies. But this helps a lot as well.

5. Flexible Operations:

Due to the load balancing servers It helps the IT people to work in a more flexible way and they can easily manage the servers and maintain them. Due to load balancing IT people can schedule their tasks and maintain the servers even without affecting the application, Or without any downtime. Because it helps application response from a single server when the other servers are under maintenance. So, this enhances the efficiency of the application and program.

Disadvantages of Load Balancers

1. Limitations in Some Geographic Environments:

Some of the load balancing algorithms are perfect for small area implementation, But the devices which are in remote locations suffer from many issues. Like network pause, Interruption in communication, And the space between the client and the server can’t be considered and solved. 

2. Load Balancers are difficult to keep up with the new technologies:

New technologies like AI, Blockchain, IoT and cloud services increase the expectation of the user. And the load balancer should be compatible with that and should have good processing speed, Storage capacity and different system functionalities to keep up with the latest trends. While it is a challenging task to maintain the load balancers’ algorithms with the latest tech advancements.

3. Centralized Node Problem:

Many load balancers are based on a single centralized node, Which means that if in any case the centralized node would be compromised then the whole setup would collapse. So, to handle that it is the best practice to configure multiple nodes for security reasons and to prevent downtime. 

4. Complexity of Load Balancing Algorithms:

Some load balancing algorithms are so complex that not only do they impact the overall performance, But also affect the speed, Response and migration time. Even with extreme burden load balancers should provide the best possible results. 

Load Balancing Algorithms?

An algorithm is a set of rules and regulations which evaluates the functioning of a computer program. And load balancing uses load-balancer algorithms that are designed in a way to divide and distribute the traffic into the servers of the network. 

Although, static algorithms are available which divides and distributes the network traffic equally on all the servers. But most applications do not implement this, Because of the low performance. And instead they use dynamic load balancing algorithms which distribute traffic as per the needs. Some of the load-balancing algorithms are:

1. Weighted Round Robin Algorithm:

The weighted round robin algorithm provides the capability to divide the inbound client requests, Throughout the whole server clustering. That too as per the proportional capacity of the server, It could be a simple rotation in servers as well. 

2. Round Robin Algorithms:

The incoming client requests would be distributed and divided across the available array of servers. Like if you have 4 servers, The first request will be redirected to the first server, The second request to the second server, Third to third, Fourth to fourth. And the fifth request will be diverted to the first server. 

3. Hash:

This load balancing algorithm divides the request as per the specified parameters you define. Like if you configure a server to handle a specific IP address or to handle a specific URL then this algorithm will redirect all the requests related to it to that specific server. 

4. Least Connection Algorithm:

With this load-balancing algorithm the new client request will be redirected to the server which has been handling the fewest request amongst all. With this it’ll help all the servers to cater around an equal amount of requests. 

5. Fixed Weighted Load Balancing Algorithm:

In this algorithm the administrator puts specific weight to each server as their capability to handle the traffic requests. 

6. Adaptive Load Balancing Algorithm:

With this algorithm when a new request comes from the back-end, the agent indicates the status and then the load balancer decides which server would be the best to handle that specific request. 

7. Two random servers:

This algorithm chooses any of the two available servers randomly and then sends the request to the one with the least connection. 

All of these algorithms are efficient as per the use case, Complexity of the application, Requirement, Possible amount of traffic to handle, Hardware servers or the usage of geographical servers. So, it is very crucial to make a plan about how the application would cater immense traffic. As with the development process it will become easier. Although, Even after development the migration can be done. But the best practice is to choose a type of load balancing as per the requirements for giving users the ideal experience, Reduce network related errors, Good uptime, Quick response. And all of these features are very important for providing the best possible result to the users. 

Conclusion:

A load balancer is a hardware and software tool, That is used to handle and manage the traffic on the server. There are plenty of different efficient load balancing types and algorithms, And by using that one can achieve great results, Like a smooth and fast application without any lagging. There are both pros and cons of using load balancers, The pros include enhanced uptime, Boost performance, Flexible IT operations, And scaling of applications etc. And the cons includes limitations in some geographic environments, Centralized node problem, And complexity of load balancing algorithms.