Tag: Load balancing

Network

3 types of Load Balancing

Load balancing is a method of traffic management that will redirect the incoming traffic to your multiple servers. That way, non of them will get all the traffic, they will be able to manage less traffic better, and your network will be stronger. Now we will look 3 types of Load Balancing and how do they differ from one another.

Network load balancing

The network load balancing is ideal for balancing TCP and UDP traffic from clients over the internet. It operates on Layer 4 (the transport layer) of the OSI model (Open Systems Interconnection Model). When the network load balancer receives the traffic, it uses its algorithm and directs the traffic to one of the predefined servers in its list. It opens a TCP connection on the designated port and forwards the requests without modifying them. Not modifying them, but also not inspecting them, which means that the traffic is not checked about malicious packets, not it is organized based on the type of traffic it is. The focus here is just to transfer the traffic to various servers that are on the network.

You can use it when you are expecting large TCP or UDP traffic spikes, and you want to keep the packets unchanged.

It is easy to set up, scalable and it can save you during times of extreme traffic.

Classic

The Classic load balancing is very similar to network load balancing. It also can manage TCP and UDP, but also SSL, HTTP, and HTTPS traffic. The big difference here is that it works both on Layer 4 and Layer 7 of the OSI model. It has 3 components: the Classic load balancing instances, Listeners, and the Back-end servers.

The CLB instances will capture the traffic and distribute it to the Backed servers.

The Listeners will check the Back-end servers and see if they are functional. If any of them is down, they will give instruction to the CLB not to direct traffic to them until they are back in order.

The Classic load balancing is relatively economical, easy to set up, and provides good availability.

It also supports sticky sessions, so if a client connects to a particular Back-end server, it will stick to it and won’t go and connect to another for the time of the session.

Application load balancing

The Application load balancing works only on layer 7 (the application layer) of the OSI model. Here the load balancer is more intelligent and uses many parameters like hostname, host location (IP address), port number, and other parameters of the query. It supports protocols like HTTP, HTTPS, and WebSockets. It supports a sticky session that keeps the session open and doesn’t redirect to another instance. The Application load balancer checks the Back-end servers for different parameters and can take more advanced decisions regarding traffic distribution. It has the same components as the Classic one: load balancers, listeners, and back-end servers.

These are the 3 types of Load Balancing. You should pay attention to the protocols they use and at what level of the OSI model they work to properly understand them.

DNS

DNS – a key piece of the Internet

DNS is one of the most important and essential pieces when it comes to the Internet. Without it, it will be very hard for humans to search, connect, and explore different websites. So, let’s explain a little bit more about it!

What is DNS?

Thanks to the Domain Name System (DNS), we are able to use the Internet as simple as it is in present days. However, it is an infrastructure with vast functionality. In its foundation is the database with all of the domain names and their corresponding IP addresses.

A long DNS process is triggered once a user types a domain name for connecting with it. So, the domain name has to be translated to a language that machines understand, which are the IP addresses. That is necessary because the machines communicate with one and another through numbers. Finally, when the IP address corresponding to the domain name is resolved, it can be delivered to the browser of the user. So, the user is able to reach and explore the website. In the time when DNS was not created yet, the user would have to type an IP address, for instance, 56.155.208.13. Instead, it is much easier to remember and type a domain name, for example, domain.com. Thus, DNS gave the opportunity for humans to use the Internet and successfully communicate with machines efficiently.

What is DNS used for?

  • It makes searching on the Internet flexible, easy, and simple.
  • The Domain resolution process is crucial.
  • Load balancing
  • DNS caching
  • Email servers and routing the messages
  • Additionally, for service’s routing
  • Verifying of services, servers, e-mails, and so on.

What is the structure of DNS?

The domain name space has a structure on several levels, and various DNS servers are positioned all around the world. On the top of the structure above all stands the root. The level below is for different top-level domains (TLDs). Under them are the secondary domains and subdomains.

Root level – This is the origin of the DNS. When the DNS resolution process is initiated, the search starts from this level. After that, it proceeds to one of the name servers for the domain’s TLD. It is represented with a dot “.” at the end of the domain name. However, everyday users don’t use it.

TLD level – The top-level domains are every extension you have probably seen, such as .com, .net, .co.uk, .info, and so on. Within the TLD name servers, you are going to receive the answer, for which name servers hold the information about the domain name you are seeking for.

Second level domain. This is the name of the website that you are searching for without the TLD extension. For instance, Google, from google.com.

Subdomain level – This is the subpart of the domain name. You can see it before the domain name. Moreover, it is divided by a dot (“.”). For instance, a blog subdomain is blog.google.com.

Why is it so important?

DNS is so essential because, without it, every action on the Internet is going to take a more prolonged time, and it is going to challenge us, humans, to memorize a bunch of information. The DNS assists communication on the Internet, plus it makes domain name queries seem so fast and straightforward. Thanks to the system, you can connect to nearly every website 24/7.