The network load balancer (NLB) is an appliance that sits in front of your web servers and distributes incoming requests to them based on the IP address of the client.
The NLB will typically have multiple ports open for incoming connections from clients, and each port can be assigned to a different server.
When you use a load balancer like this, it’s called “sticky sessions” or “sticky cookies” because the browser remembers which server it connected to last time, so subsequent requests are sent to the same server.
Users can easily navigate between pages on your site without having to re-enter their login information every time they visit a new page.
When to use a network load balancer?
If you need to make sure that all traffic goes through one server at any given moment, then a network load balancer is what you need. For example, if you run a website where people can upload images, but don’t want anyone else to access those images until they’re approved by a moderator, then you’d probably want to make sure that only one image is being displayed at any given time.
If you want to distribute traffic evenly across several servers, then a load balancer isn’t necessary. However, if you do want to spread out the work among several servers, then using a load balancer may help with performance issues.
How does a network load balancer work?
A network load balancer works by listening on a single port and distributing incoming requests to several servers behind it. Each request is passed through the load balancer, and the load balancer determines which server to send the request based on the IP address associated with the request.
Once the request reaches its destination, the load balancer passes the response back to the original client.
What types of load balancers exist?
There are two main categories of load balancers: hardware and software. Hardware load balancers are appliances that sit in front of your servers and are usually very expensive. Software load balancers are much cheaper than hardware load balancers but aren’t as powerful.
Hardware load balancers include:
- Application Delivery Controllers (ADCs)
- Content Delivery Networks (CDNs)
- Edge Servers
Software load balancers include:
- Web Server Load Balancers (WS LBs)
- Reverse Proxy Servers
- Virtual Private Servers (VPSes)
- Cloud Load Balancers
Choosing the Right Load Balancer
The first thing you need to keep in mind when choosing a load balancer is how many servers you want to add. Do you want to add a couple of servers, or dozens?
You also need to consider whether you want to use a hardware or software load balancer. Hardware load balancers are expensive than software load balancers, but they offer greater flexibility. They allow you to configure multiple rules per server, so you can easily set different policies for each server.
Moreover, also keep in mind the kind of workload you expect to see. Will you have lots of small files, or large ones? How often will users hit your site? What sort of content will they be viewing? These questions will help you determine which load balancing technology is right for you.
Now another step is choosing between a web-based or appliance-based load balancer. You can get both kinds of load balancers, but there are pros and cons to each.
Web-Based Load Balancers
- Easy to install
- Can be used with almost any application
- Requires constant maintenance
- Doesn’t provide advanced functionality
Appliance-Based Load Balancers
- More flexible
- Provides advanced functionality
- Harder to maintain
What type of load balancer is best for me?
It depends! If you just want to balance traffic across a few servers, then a WS LB might be enough. But if you want to scale up to hundreds of servers, then a CDN would be better suited. A CDN has more features than a WS LB, including: • Geo distribution
- DDoS protection
- SSL offloading
- HTTP/2 support
- Dynamic DNS
- Traffic shaping
- High availability
Does Network Load Balancer cost more?
The costs associated with load balancing differ depending on what type of load balancer you decide to use. For example, there are different types of load balancers available to handle both network traffic and application traffic.
In addition, some load balancers offer features such as health checks, SSL termination, and failover capabilities. When choosing a load balancer, it’s important to consider how much you want to pay, the number of resources required to manage the load balancer, and whether the load balancer provides sufficient functionality. However, you may look for a public cloud provider who offers affordable load balancing solutions.
The bottom line
The method of load balancing is frequently used to improve the performance of websites. It helps keep your servers busy, while also making navigation easier for visitors. The most popular way to implement load balancing is with a web server load balancer.