What is Round Robin Load Balancing?

Round Robin Load Balancing is a simple technique for spreading incoming traffic across multiple servers. It cyclically forwards client requests via a group of servers to effectively balance the server load. It is excellent in cases when the servers are very similar in their computational and storage capacities. 

Round Robin Load Balancing is most commonly used because of its simplicity. Its implementation is rather straightforward. It is a distributor that redirects the traffic from different users to the servers in order. Let’s see an example. Imagine you have 6 users (u1, u2, u3, u4, u5 and u6) who want to connect and you have 3 servers (s1, s2 and s3). U1 will connect to s1, u2 to s2, u3 to s3 and it will start all over again u4 to s1, u5 to s2 and u6 to s3. Can you guess to which will it connect the next user 7? Yes, it will connect to s1.

It takes into account just when somebody wants to connect. Nothing more. It will definitely serve as a load balance, based on this logic, but ignore all other parameters. So you will have reduced load on the network, but you can have different problems.

Maybe your servers are not equal. Imagine server 1 (s1) is a lot faster than the rest. With more RAM, better CPU, etc. It will still receive the same traffic as the rest which are weaker. It is not the most efficient scenario. For that reason, Round Robin Load Balancing works best with the same configuration of servers.

How does Round Robin Load balancing work?

Round Robin Load Balancing functions under a very easy-to-understand mechanism. As we mentioned earlier, this technique forwards requests cyclically between servers. They are sequenced depending on the order they arrive. This mechanism is especially helpful during high incoming traffic and keeps the load balanced. 

Here is an illustration of how Round Robin Load Balancing actually works. Let’s imagine a company that holds a group of four servers: A, B, C, and D, and many users send requests to connect with their website:  

• Server A gets request 1
• Server B gets request 2
• Server C gets request 3
• Server D gets request 4

The rotation starts all over again when the load balancer continues to send requests to servers. 

But what if one of the servers has the capacity to handle more requests compared to others? Then you can implement Weighted Round Robin (WRR)!

Weighted Round Robin (WRR)

Weighted Round Robin is a little bit more advanced configuration for balancing the load. Yet, it is a perfect opportunity if one of your servers has better characteristics than the rest. The administrator can assign weight to every server in the group based on chosen criteria. In a most popular scenario, the criterion is the server’s traffic‑handling capacity.

This variation of Round Robin takes into account the previous case, where one server is better than the rest. Imagine the s1 is twice more powerful than s2 and s3. We will assign it higher weight because it can handle a more significant load. Because we did this, it will get more traffic.

Following the example, u1 will connect to s1, then u2 will again connect to s1. This is the main difference. U3 will connect to s2, u4 to s3, then again u5 to s1 and u6 to s1. U7 will connect to s2.
There is another scenario where Weighted Round Robin can be useful. Maybe your servers are similar, but you have more important information in one, you want it to have less weight. So, it that case you assign higher values to the rest of the servers. This way they will handle more load and your essential server will have less work and less chance to crush.

Suggested article: What is Load Balancing?

Advantages and Disadvantages

Round Robin is a simple and widely used load balancing algorithm that distributes incoming network traffic across a group of servers. Like any other method, it has its own set of advantages and disadvantages. Here are the main benefits and drawbacks of the Round Robin Load Balancing mechanism:

Advantages

• Simplicity: It is an easy-to-understand and easy-to-apply technique. Additionally, it does not require much effort to set up, works on a clear mechanism, and has an uncomplicated framework.
• Even Distribution: It provides a relatively even distribution of incoming requests across the available servers. Each server gets an equal share of the load, which is beneficial when all servers have similar processing capabilities.
• Low Latency: Round Robin is generally low in terms of latency because it doesn’t involve complex decision-making processes. It simply follows a predictable rotation.
• Scalability: Round Robin is easy to scale horizontally. When you add more servers to your pool, they can be smoothly integrated into the rotation without major reconfiguration.

Disadvantages

• Deficiency of functionalities: The simplicity of this mechanism is also its main drawback. Many experienced administrators prefer to utilize Weighted Round Robin or more complicated algorithms. 
• Lack of Intelligence: Round Robin doesn’t consider the actual load or health of individual servers. It treats all servers as equal, which can be problematic if some servers are underutilized while others are overloaded. This can lead to inefficient resource allocation.
• Stateless Nature: It’s a stateless algorithm, meaning it doesn’t consider the current state of the server (like CPU load or memory usage). This lack of awareness can lead to not-so-optimal performance.

Can I use Round Robin Load Balancing with ClouDNS?

Yes, you can use Round Robin Load Balancing with ClouDNS. It is an included feature in both paid and free plans. You can easily sign up for a free account.

Here’s how you can use Round Robin load balancing with ClouDNS:

1. Register your domain with ClouDNS: If you haven’t already, register your domain with ClouDNS or transfer your existing domain to our DNS service.
2. Create DNS records: In the ClouDNS control panel, you can easily create DNS records. For Round Robin load balancing, you can use A records, AAAA records and ALIAS records, but you can’t use CNAME records with any other DNS record for the same host.
3. Set TTL values: Configure the Time to Live (TTL) values for your DNS records. TTL determines how long DNS resolvers should cache the DNS records. 
4. Regularly update DNS records: If you need to add or remove servers from the load balancing pool, you can do so by updating the DNS records in the ClouDNS Control Panel.
5. Monitor and optimize: Regularly monitor the performance of your load balancing setup and make adjustments as necessary to ensure that traffic is evenly distributed.

If you have any additional questions, you can contact our 24/7 Live chat support!

When to Use Round Robin Load Balancing

Round Robin Load Balancing is ideal for scenarios where all servers in the pool have similar resources and capacity. It is well-suited for small to medium-scale applications where even traffic distribution is the main concern. For example, small businesses with limited servers can effectively use this method to ensure their websites or applications stay responsive and balanced under normal traffic conditions.

However, if your infrastructure has servers with varying performance levels or inconsistent resource availability, more advanced load balancing algorithms like Weighted Round Robin or Least Connections may be necessary. Understanding when to use Round Robin is key to optimizing its efficiency in your particular setup.

Round Robin vs. Other Load Balancing Algorithms

Round Robin is just one of many load balancing algorithms. Depending on your needs, other methods may be more suitable:

• Least Connections: This algorithm directs new requests to the server with the fewest active connections, which can help ensure better resource utilization when server loads vary significantly.
• IP Hash: This method directs traffic based on the client’s IP address. It ensures that each client consistently connects to the same server, which is beneficial for maintaining session consistency.
• Weighted Least Connections: This approach combines the advantages of Least Connections and Weighted Round Robin, ensuring that more powerful servers handle more connections while still considering their current load.

Common Use Cases

Round Robin Load Balancing is commonly used in the following scenarios:

• Web Hosting: Distributing web traffic evenly across a set of identical servers to balance the load and prevent any one server from becoming overwhelmed.
• Content Delivery Networks (CDNs): In some CDN setups, Round Robin Load Balancing can be used to distribute content requests across different servers in the network, helping to ensure faster delivery.
• E-commerce Websites: Small to mid-sized e-commerce sites may use Round Robin to distribute user sessions across multiple servers, ensuring that no single server handles too much traffic during peak shopping times.

Conclusion

Round Robin Load balancing is a fundamental technique for distributing network traffic efficiently across multiple servers. It offers a simple and easy-to-implement method for ensuring optimal resource utilization and high availability. By cyclically assigning incoming requests to servers in a sequential manner, Round Robin helps prevent overload on any single server, facilitating fault tolerance and load distribution. While it may not consider server health or actual load, it serves as a cost-effective solution for basic load distribution requirements. However, for more complex scenarios, advanced load balancing algorithms may be preferred. Finally, Round Robin Load balancing remains a valuable tool in the arsenal of network administrators.

The post Round Robin Load Balancing. Simple and efficient appeared first on ClouDNS Blog.

Load Balancing – Definition

The network performance has become incredibly important. No matter if your organization is big or small, you don’t want to experience operational issues or network reliability problems. Load Balancing manages the demand by distributing the traffic and the application load over different servers depending on their current load.

It is not a new invention. In its early days, it was used between the end device and the application servers to check the servers and to send traffic to the least occupied.

But with the evolving of the networks, load balancing has gotten a new shape. Now it is not a simple distribution system. The load balancing has become very divided.

Here are some Load Balancing examples:

• There is application load balancer which distributes one single application over the servers; there is another which distributes only between the server cluster; another directs the traffic from multiple paths to a single destination.
• Other load balancing solutions are very advanced. They can shape the traffic and act as intelligent traffic switches, do different health checks on the content, applications, and servers, add extra security on the network and protect it from malicious software and improve availability.

Choosing load balancing is hard. You need to think about the demands on your networks and servers. You need 100% reliability on every part. If one component fails, this can lead to downtime.

Why Do You Need Load Balancing?

Load balancing is crucial for optimizing the performance, reliability, and scalability of your online services. Without it, a single server could become a bottleneck, causing downtime or even crashes during periods of high traffic. Load balancing helps distribute traffic efficiently across multiple servers, reducing the risk of server overloads and ensuring uninterrupted service. It also enhances user experience by providing faster response times and higher availability. Furthermore, load balancers help protect your infrastructure against DDoS attacks by distributing malicious traffic across multiple servers. It is particularly important for businesses with high traffic volumes or mission-critical services, as it can help maintain uptime and performance consistency. Another significant reason for adopting this mechanism is its scalability. As your website grows, adding more servers is a standard solution to manage the increased traffic load. Load balancing enables this growth by ensuring that new servers are smoothly integrated into your system without affecting overall performance.

How does it work?

Load balancing is achieved and managed with a tool or application that is called a load balancer. Despite the form of the load balancer (hardware or software), its main goal is to spread the network traffic among different servers and prevent overloading. 

Here are several steps which explain how load balancing works:

1. Your website receives traffic. Once users reach your website, they send a lot of requests to your server at the same time. 
2. The traffic is spread toward the server resources. The load balancer (hardware or software) intercepts and examines every request. Then, it directs it to the most suitable server node.
3. Every server works with a reasonable workload. The server node receives the request. When it is able to accept it, the server notifies the load balancer that it is not overloaded with too many requests.
4. The server answers the request. In order to complete the process, the server sends the response back to the user.

Whenever a user request arrives, the load balancer directs it to a precise server. The process repeats for every request. Load balancers are responsible for deciding which server is going to receive a precise request. That is determined based on different techniques for load balancing.

Types of Load Balancing

There are three appliances of Load Balancing – Physical, Virtual and Cloud-based.

Physical Appliance

This is the most traditional approach. The load balancer is placed right after the firewall and before the server cluster. Now you can expect the balancer to include more advanced functions like a built-in firewall and to be the all-in-one gatekeeper of the network.

There are other subtypes to the Physical. Some load balancers serve as caching devices, others like SSL accelerators or ADCs.

They are all physically present in the same data center as the application servers. The benefits that they provide are easy controlled and easy to connect and form bigger structures.

The negative part is that they are costly, you need to buy a lot of hardware and software to control them and lack geographical distribution.

Virtual Appliance

In the previous appliance, the main accent was put on hardware; here we don’t have a specific hardware. It runs on a virtual machine. This virtual machine provides the environment where the load balancing software works. It is a lot easier to apply because it can run on different computer configurations. It is cheap as well, and you can buy less expensive servers; the focus goes on the software, not on the hardware; it is easier to back up.

As for disadvantages, we can mention the problem with choosing a virtualization platform, and patches and upgrades can sometimes hurt the system.

Cloud-based Load Balancing

This is a convenient and robust solution for bigger networks. It is based on the cloud, and there it handles the load balancing and other functions like failover.

It manages interruptions, network problems, and outages far better and it can easily redistribute the traffic. Some other benefits of using Cloud-based Load Balancing are:

• Speed – it significantly reduces the response times and reduces the load on applications and web servers.
• Security – at load balancer level, DDoS attacks can be blocked and prevented.
• Low starting cost – you don’t need to buy software, nor expensive hardware. It is a service that you choose based on your current needs, and it is easily upgradable.

If you want to manage your DNS traffic (DNS requests) more efficiently, you can implement Load balancing in one of the following ways:

• Round Robin DNS

Round Robin DNS is a technique of load distribution, load balancing, or fault-tolerance provisioning multiple, redundant Internet Protocol service hosts (e.g. Web server, FTP servers), by managing the Domain Name System’s (DNS) responses to address requests from client computers according to an appropriate statistical model.

Round Robin DNS is often used to load balance requests between a number of Web servers. You can find more information regarding Round Robin DNS and how to use it here.

• GeoDNS

The GeoDNS service allows you to redirect your customers to specific IPs (servers) based on their geographic location. The service allows you to build your own CDN or to load balance your traffic. It is more accurate and smart than the Round-Robin. You can also set up different websites for each geolocation region. You can find detailed information regarding GeoDNS here.

Load Balancing Benefits

Load balancing is all about improving the management of network traffic and making the user experience better. Therefore, the benefits it provides are the following:

• Scalability: If you notice a drop or spikes in your traffic, you can easily increase or decrease the number of your servers to satisfy urgent requirements. That way, you can handle sudden massive amounts of requests. They usually appear, for instance, during a promotion or holiday sales.
• Redundancy: When you have the ability to maintain your website on multiple servers, you can ensure excellent uptime. Relying only on one web server hides a lot of risks that will force your visitors to leave your website. Load balancing is key if you can’t afford downtime.
• Flexibility: Load balancing gives you the ability to redirect traffic from one server to another. So that way, you have the flexibility to perform your regular maintenance work without disturbing the normal operations of your website.
• Avoid failures: Load balancing can be very helpful for avoiding failures. It spreads large amounts of traffic to the available servers and prevents outages. You can manage the servers efficiently and precisely. It is best if they are distributed across several data centers.
• DDoS attack protection: Spreading traffic across servers is also valuable when protecting against Distributed Denial of Service (DDoS) attacks. Load balancing helps when a particular server gets flooded with malicious traffic by a DDoS attack. The traffic is forwarded to many servers rather than just one, and the attack surface is reduced. This way, load balancing eliminates single points of failure, and your network is resilient against such attacks.

Who can benefit from load balancing?

Here are the organizations and sectors that can benefit significantly from load balancing:

• Websites and E-commerce: Websites with high traffic, online retailers, and e-commerce platforms benefit from load balancing to ensure fast page loading, minimal downtime, and a seamless user experience.
• Cloud Service Providers: Companies offering cloud-based services rely on this technique to distribute workloads across servers, ensuring scalability and fault tolerance for their customers.
• Enterprises: Large enterprises use load balancing to evenly distribute network traffic across servers, preventing overloads, optimizing resource utilization, and maintaining system stability.
• Content Delivery Networks (CDNs): CDNs use the mechanism to efficiently deliver content to users, reducing latency and improving the delivery of multimedia, software updates, and web content.
• Gaming Industry: Online gaming companies utilize it to handle multiplayer game traffic, reduce lag, maintain game responsiveness, and ensure a smooth gaming experience.
• Healthcare and Telecommunications: Critical sectors like healthcare and telecom rely on load balancing for fault tolerance and high availability, ensuring that vital services remain accessible even during peak loads or server failures.
• Internet Service Providers (ISPs): ISPs can optimize network traffic, improving internet connectivity for their customers and efficiently managing the load.
• Government and Educational Institutions: These organizations employ load balancing to handle high volumes of traffic on their websites and online resources, ensuring accessibility and reliability.

Best Practices

When implementing the load balancing mechanism, it is important to follow the best practices, which are the following:

• Implement Health Checks

Always use health checks to monitor the status of your servers. Regular monitoring ensures that traffic is routed only to functioning servers, preventing requests from being sent to unresponsive or slow servers, which can negatively affect the user experience. Health checks allow your load balancer to automatically exclude problem servers and reintroduce them once they are back online.

• Select the Right Type of Load Balancer

Choosing the appropriate load balancer for your needs is key. Hardware, software, and cloud-based load balancers each offer different advantages. For small businesses, a cloud-based load balancer can offer flexibility and scalability, while enterprises with complex needs may benefit from physical or hybrid solutions. Consider your traffic type, load, and future growth when making a decision.

• Prioritize Redundancy and Failover Plans

Always ensure you have redundancy built into your load balancing setup. A backup or failover load balancer should be in place to take over in case the primary one fails. This ensures that traffic continues to flow smoothly even during server or network outages, thereby maintaining high availability for your users.

• Enhance Security

Load balancers are a frontline defense against Distributed Denial-of-Service (DDoS) attacks and other malicious traffic. By distributing traffic, they prevent bottlenecks that attackers aim to exploit. Implement DDoS protection strategies alongside load balancing, such as limiting excessive connections from a single source and setting up rate-limiting rules.

• Leverage Geo-based Load Balancing

For global businesses, using geo-based load balancing can significantly improve the user experience. This strategy directs users to the server closest to their geographic location, reducing latency and speeding up content delivery. By leveraging GeoDNS, businesses can ensure that customers experience fast, reliable service no matter where they are located.

• Monitor and Optimize Regularly

After setting up load balancing, ongoing monitoring and optimization are crucial to maintaining performance. Regularly assess traffic patterns, response times, and server health to ensure the configuration continues to meet your needs. Make adjustments as your infrastructure or traffic load changes to keep everything running smoothly.

Conclusion

As always you should know the needs of your organization to choose how exactly to implement the load balancing. Based on the advantages we recommend to start with a Cloud-based Load Balancing. You can sign up for free to use Round Robin DNS or if you want to use the more advanced GeoDNS service, you can find details about prices and features on our website.

The post What is Load Balancing? appeared first on ClouDNS Blog.

SYN flood attack: Origin and Basics

In the 1990s, a man named Wietse Venema explained a certain attack method in-depth. On its surface, the concept seems innocuous enough. In a network protocol, namely TCP, a three-way handshake commences communication. Imagine this as a modern chivalry ritual between your computer and the server you want to engage with.

1. You send a SYN (synchronize) packet: “Hi, can we chat?“
2. Server sends back SYN-ACK (acknowledgment): “Sure, let’s talk.“
3. You finish with an ACK: “Cool, let’s get started.“

What SYN flood attack is?

Broadly speaking, a SYN flood attack, also referred to as a TCP/IP-based attack, is a type of Denial of Service (DDoS) attack on a system. It might be compared to an irritating prankster continuously dialing a business phone to keep the line busy and prevent legitimate callers from reaching the establishment. The attacker here sends a flood of SYN requests from either a single or multiple spoofed IP addresses to a server with the malicious intent to halt the server’s functionality to process new incoming service requests. As the server gets trapped in a vicious cycle of responding to these inexistent or half-open connections, it can lead to crashing or becoming unavailable to legitimate users.

How does it work? 

The mechanics of a SYN flood operate in a methodical sequence of steps that exploit the TCP handshake protocol. Let’s break it down for clarity:

Step 1: Identifying the Target

The attacker first picks out the target server. Usually, they’re gunning for a specific service, like a website or an application hosted on that server.

Step 2: Initiating SYN Requests

Here, the attacker commences the mischief by generating a multitude of SYN packets. Each of these SYN packets asks the server, in essence, for permission to establish a connection.

Step 3: Half-Open Connections

Upon receiving a SYN request, the server reciprocates with a SYN-ACK packet and moves the corresponding request to a backlog queue. This places the connection in a “half-open” state, awaiting the client’s final ACK for completion.

Step 4: Server Response

At this juncture, the attacker ghosts the server, never sending the final ACK to complete the handshake. Consequently, the server’s backlog queue starts brimming with incomplete handshakes.

Step 5: Resource Exhaustion

With each half-open connection, the server allocates a chunk of its resources. As these incomplete connections accrue, the server begins to hit its limit on resources.

Step 6: Denial of Service

At this point, the server becomes unable to accept any new connections. Legitimate users trying to connect encounter timeouts or failures, achieving the attacker’s endgame of denying service.

Types of SYN Flood Attacks

SYN flood attacks can take on multiple forms, each with its own level of complexity and associated risks:

1. Direct Attack: In this type of attack, the attacker does not hide their IP address, meaning that all traffic comes from a single source. This makes it relatively easier for network administrators to identify and block the attack by filtering the IP address. However, direct attacks can still overwhelm a server, especially if they come from high-capacity sources.
2. Spoofed Attack: Here, the attacker sends SYN requests using spoofed IP addresses, making it difficult to track the origin of the traffic. The server tries to send SYN-ACK packets to non-existent or unreachable IPs, leaving the connections open and slowly exhausting server resources​. Spoofing adds an extra layer of complexity, making it harder to mitigate, as simply blocking the traffic source won’t solve the problem.
3. Distributed Attack (DDoS): In a distributed SYN flood attack, the attacker uses a botnet – a network of compromised devices – to send SYN requests from various IP addresses. This creates massive amounts of traffic from multiple sources, overwhelming the server and making it extremely difficult to pinpoint and block the attack. This method was infamously used by the Mirai botnet, which leveraged IoT devices to launch one of the largest DDoS attacks in history​.

Ways to mitigate the SYN flood attack

Ah, but there’s hope! Multiple strategies can serve as lifelines in mitigating the fallout from a SYN flood.

SYN cookies

Implementing SYN cookies proves useful in minimizing risk. When deployed, the server doesn’t allocate resources right away for a new SYN request. Rather, it converts the connection into a unique cryptographic cookie. Only when the handshake gets completed does the server expend resources, reducing vulnerability to attacks.

Rate limiting

Another solid tactic involves imposing rate limiting on incoming SYN packets. By setting a strict threshold for the number of allowable new connections per unit of time, the server can effectively nip malicious flood attempts in the bud.

DDoS Protection

Incorporating DDoS protection is an advanced, indispensable strategy. These specialized solutions not only defend against SYN flood attacks but also guard against a broader range of DDoS threats. DDoS protection services usually feature large traffic scrubbing networks that can sift through immense volumes of data, allowing legitimate traffic through while blocking malicious requests.

Anycast DNS

Anycast DNS serves as another invaluable layer of defense. By distributing incoming traffic across multiple data centers (PoPs), it minimizes the load on any single server. This distribution can effectively dilute a SYN flood attack, rendering it far less potent. Anycast DNS is especially beneficial when used in conjunction with DDoS protection services, providing an additional layer of robust, scalable defense.

Robust Load balancers
High-capacity load balancers can significantly improve your system’s capacity to manage an enormous volume of connection requests. In turn, this can enhance your network’s ability to resist SYN flood attacks.

Monitoring services
Real-time Monitoring services track and scrutinize network patterns, activities, and performance, enabling the early detection of potential threats or attacks. These services can monitor server health, network performance, and traffic patterns, thereby identifying and alerting about possible anomalies that might indicate a SYN flood attack.

Firewall rules

Tweaking firewall configurations can also be invaluable. For instance, you can set rules to block incoming requests from a specific IP address if it exceeds a set number of SYN requests within a short timeframe.

Suggested article: Router vs firewall

Consequences of non-protection

• Service disruption: SYN flood attacks can result in service disruption or downtime, as the targeted server becomes overwhelmed and unable to handle legitimate requests.
• Financial loss: Downtime can lead to financial losses for businesses, especially e-commerce websites, online services, and organizations heavily reliant on internet connectivity.
• Reputation damage: Frequent DDoS attacks, including SYN floods, can tarnish a company’s reputation, eroding trust and customer confidence.
• Security overhaul costs: Post-attack, merely patching vulnerabilities won’t suffice. A complete revamp of security protocols becomes vital, often draining both time and financial resources.

Conclusion

In a world increasingly reliant on digital technology, understanding and defending against threats like SYN flood attacks is crucial. While they are a potent threat, solutions such as SYN cookies and robust load balancers offer effective means of mitigation. In essence, maintaining cybersecurity is not just a good idea, but a necessity in today’s digital landscape.

The post Understanding SYN flood attack appeared first on ClouDNS Blog.

Why do we need load balancing?

With the massive increase of the internet traffic each year, it is getting harder to provide a sustainable service for all the millions of clients without having some downtime. For this purpose, you need to apply a model of load balancing, that will reduce the load caused by the countless users trying to reach your website or use your application.

Another reason why you need to use load balancing is the rising number of DDoS attacks. To evade them you will need to spread the traffic to as many as possible servers that you have. That way, their combined efforts can resist the wave of high traffic.

DNS load balancing explained

DNS load balancing is a technique that distributes incoming web traffic across several DNS servers by associating a single domain name with multiple IP addresses (IPv4 and IPv6). When users request the domain, DNS servers provide different IP addresses in a DNS Round-Robin fashion or based on other algorithms that help effectively spread the load. That way, traffic is distributed across multiple servers, preventing any single server from becoming overwhelmed and maintaining overall service availability.

Pros of DNS load balancing

Some of the main benefits of DNS load balancing include the following:

• Easy to Implement: It doesn’t require specialized hardware and can be implemented by only configuring DNS records. That makes it an excellent choice for businesses of all sizes.
• Geographic Distribution: It can also be utilized to direct users to servers in different geographic locations. As a result, it improves performance by reducing latency for users located at different points all over the world.
• Scalability: Adding or removing servers from the load balancing pool is a relatively easy and simple process. That makes it suitable for applications that experience changing levels of traffic.

Cons of DNS load balancing

Here are several things you should consider before implementing this technique:

• TTL Impact: DNS records have a Time-to-Live (TTL) value, which determines how long a DNS response is cached. Changing load balancing configurations might take time to propagate due to the caching mechanism.
• Limited Monitoring: It lacks real-time awareness of server health. If a server becomes unavailable, DNS will still route traffic to it until the DNS cache expires. To avoid that, you can implement a Monitoring service to help identify potential issues quickly.

Hardware load balancer (HLB)

HLBs are the first to appear sometime in the late 90s. They are hardware, which means you need to purchase the device and connect it to your network. Hardware load balancing (HLB) distributes traffic across multiple servers depending on the servers’ process power, the connections, usage of resources or randomly.

The hardware load balancers are implemented on Layer4 (Transport layer) and Layer7 (Application layer). On Layer4 it makes use of TCP, UDP and SCTP transport layer protocol details to make decision on which server the data is to be sent.

Suggested article: Comprehensive Guide on TCP Monitoring vs. UDP Monitoring

On Layer7, the hardware forms an ADN (Application delivery network) and passes on requests to the servers as per the type of the content.

Pros of Hardware load balancing

Here are the primary benefits of Hardware load balancing:

• Advanced Features: Hardware load balancers can perform complex traffic distribution algorithms, considering factors like server health, response times, and content-based routing, leading to more efficient traffic distribution.
• Real-Time Monitoring: These devices continuously monitor server health and network conditions, enabling immediate traffic redirection in case of server failures or high loads.
• Enhanced Scalability: Hardware load balancers can handle large amounts of traffic and provide seamless scalability for growing services.

Cons of Hardware load balancing

Some of the drawbacks or things you should have in mind when choosing this method for load balancing are the following:

• Cost and Complexity: Implementing hardware load balancing requires a significant investment in specialized hardware devices and ongoing maintenance, which might be a barrier for small to medium-sized businesses. Configuration and management can be complex, especially for organizations without specialized networking experts.
• Single Point of Failure: While hardware load balancers enhance server availability, they themselves can become single points of failure. Proper advanced configuration is often necessary to mitigate this risk.

DNS load balancing vs. Hardware load balancing

We will compare them in two conditions, with a single data center, and with cross data center load balancing.

In the first scenario, both are very competitive. The main difference is in price. The DNS load balancer can be more accessible because usually it is offered as a subscription. In the case of HLB you must buy it and if you need extra power in the future, the upgrades can come very costly. The DNS service can be scaled easier, just by updating to another plan.

In the second scenario with cross data center, things are similar. It is getting very expensive to create a global server load balancing with the HLB because you need to properly equip every of your data center.

With global in mind, the DNS load balancing has a clear advantage over the HLB with scalability and price. The DNS option has a better failover and easy recovery.
Another advantage of the DNS load balancing is the cost to maintain. The DNS services are mostly offered as Managed DNS, so it requires less maintenance.

Which One to Choose?

Choosing between DNS load balancing and hardware load balancing largely depends on the specific needs and resources of your business.

DNS load balancing is generally more cost-effective and easier to implement, making it ideal for small to medium-sized businesses or those with inconsistent traffic levels. Its scalability and ability to direct traffic based on geographic location provide a significant advantage for globally distributed user bases. However, it’s important to consider the limitations, such as the impact of TTL on configuration changes and the lack of real-time server health monitoring, which can actually be compensated by implementing ClouDNS’s monitoring service. Despite these drawbacks, DNS load balancing offers a flexible and affordable solution for many online services.

On the other hand, hardware load balancing is better suited for enterprises requiring advanced features and robust real-time monitoring capabilities. The hardware solution offers more sophisticated traffic distribution algorithms, taking into account server health and network conditions to optimize performance. Although the initial investment and complexity in setup and maintenance are higher, hardware load balancers provide enhanced scalability and reliability for handling large volumes of traffic. They are particularly beneficial for applications requiring high availability and minimal latency.

Finally, your decision should consider the cost, desired level of control, and specific performance requirements to ensure a seamless and efficient online experience for your users.

Conclusion

Both DNS load balancing and hardware load balancing offer a good solution for distributing traffic. Which one to choose depends on the needs of your company. How tight control you would like to have? How much can you invest? Do you like a subscription model with small monthly fees or do you prefer to put a lot of money every few years to have top of the notch performance?

We recommend you to try a DNS cloud-based load balancing, like our GeoDNS.
It is cost-effective, easily scalable; you can use multiple geolocation target options and have protection from DDoS attacks.

Later you can combine it with your own hardware load balancing and create a hybrid for your specific needs.

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What is CDN?

CDN (Content Delivery Network) is a network of geographically distributed servers all around the world. Each of these servers is a PoP (Point of Presence). It has a cache of the data that the users in this specific location will use. CDN doesn’t substitute the web hosting; it just makes many cached data of the original data and stores it around the world for better accessibility. It works using the GeoDNS technology so the visitors of your website will be connected to the fastest/closest server, without the need to get the data from the web hosting. CDN saves a lot of time.

Why is it important?

A Content Delivery Network (CDN) is important because it improves the performance, scalability, and security of websites and applications. By distributing content across multiple servers located in different geographic locations, CDNs can deliver content faster and more efficiently to users. That way, it reduces latency, improves page load times, and provides a better user experience. CDNs can also handle high volumes of traffic, reducing server load and improving website scalability. Furthermore, CDNs offer security features such as DDoS protection and web application firewalls, which help protect against cyber threats. Overall, CDNs are an essential tool for modern businesses that rely on fast and efficient content delivery, global reach, and robust security.

History of CDN

Different technologies affected the birth of CDN – hierarchical caching, server farms, cache proxy deployment and improved web servers.
The first generation of CDN came around the late 90’s. People created them because of the growing use of on-demand content (audio, video, etc.). Dynamic and static content delivery. It was mostly intelligent routing and edge computer methods. The second and current generation, is cloud-based, relying on a peer-to-peer connection and it is focused on video-on-demand.

How does it work?

A Content Delivery Network (CDN) is a system of servers distributed geographically to deliver web content to users more quickly and efficiently. When a user requests a web page, the CDN provides the content from a server closer to the user’s location, reducing the time it takes to load.

The process of delivering content through a CDN typically involves the following steps:

1. A user requests a website or a specific web page from their browser.
2. The user’s request is received by the nearest CDN server, called an edge server, to their geographic location. The edge server is determined based on the user’s IP address, which reveals their location.
3. If the edge server has a cached copy of the requested content, it serves it directly to the user’s browser. Caching involves storing a copy of the content on the edge server. That way, it can be delivered more quickly to users in the future.
4. If the edge server doesn’t have a cached copy of the content, it requests it from the origin server. The origin server is the original source of the content, typically the website’s hosting server.
5. The origin server responds by sending the requested content to the edge server.
6. The edge server caches the received content from the origin server for future requests.
7. Finally, the edge server provides the requested content to the user’s browser.

By distributing content across multiple servers, a CDN can reduce the load on the origin server and provide a more reliable and scalable infrastructure for delivering content to users worldwide. Additionally, since edge servers are located closer to users, the time it takes to load web pages is significantly reduced, improving the user experience.

For who is it?

Anyone can benefit from CDN. From the big companies that we mentioned before and small blog websites. The technology increases the speed of the website and can be very useful even if you have just a WordPress blog. This helps the SEO, and your website will rank a lot better in Google, and your visitors will be happier thanks to the speed boost.

Here are some examples of who can benefit the most from implementing a CDN:

• E-commerce Platforms: E-commerce websites can experience irregular traffic patterns, especially during peak shopping seasons or promotional events. CDNs help these platforms deliver product images, videos, and web pages quickly and efficiently to customers worldwide, ensuring a seamless shopping experience and maximizing sales.
• Media and Entertainment Companies: Streaming services, gaming platforms, and content providers rely heavily on CDNs to deliver high-quality audio and video content to users across different locations, devices and platforms. CDNs minimize buffering, reduce latency, and ensure smooth playback, enhancing the overall user experience and driving engagement.
• Software Companies: Software companies distribute updates, patches, and installation files to users globally. CDNs accelerate the download process, reduce bandwidth consumption, and ensure reliable delivery of software updates, enabling users to access the latest releases quickly and securely.
• News and Publishing Websites: News websites and publishing platforms require fast and reliable content delivery to keep readers informed and engaged. CDNs ensure timely delivery of articles, images, and multimedia content, even during periods of high traffic volume or breaking news events, enhancing reader satisfaction and retention.
• Gaming Industry: Online gaming platforms depend on low-latency, high-performance networks to deliver an immersive gaming experience to players worldwide. CDNs minimize lag, reduce packet loss, and optimize server response times, providing gamers with enhanced gameplay experiences.

How to create your CDN using DNS

Benefits

CDN is able to provide numerous benefits, some of which are the following:

• The most significant benefit is definitely the speed. It reduces the latency; everything loads way faster than before. How fast? On average 70% faster!
• Load balancing. By using different PoPs around the world, the traffic gets well distributed, and it reduces the traffic on the original server.
• It reduces the bandwidth consumption, so if your web host has low bandwidth, this can help you a lot.
• It has DDoS protection. It protects you from a single point of failure, thanks to the many different PoPs.
• It will improve the SEO of your site. Google values the speed of your website as one of the key indicators for ranking in its search engine.

Conclusion

Content Delivery Networks are getting more popular thanks to its advantages. Many people start using it for E-commerce Entertainment and blog sites. It can help you over rank your competitors on the Google pages and provide a better uptime. There is no doubt that this solution is definitely worth trying!

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