18th November 2020

AVI Load Balancers-The Beginning

AVI Load Balancers-The Beginning

Load Balancers 

Load balancers have come a long way since they started from only Layer 4 load balancer services to Layer 7 load balancers we have made leaps and bounds in this area.

Starting out what even is load balancing.  This is when a task or process is distributed through resources in order to make the overall process work more efficiently, this might include reducing response time by reducing the load on one particular server and spreading it out more evenly. This is illustrated below.

The load balancer sits in front of the servers and routing client which then requests across all of the servers that are capable of fulfilling those requests to maximise speed and capacity. This makes sure none of the servers are overworked as this could degrade performance. If one server fails the load balancer will redirect the traffic to the remaining online servers. When a new server is added to the server group the load balancer automatically starts to send requests to it. The load balancer allows for high availability and reliability by only sending requests too servers that are online and provides the flexibility to add or subtract servers as the demand changes.

To look more into load balancers and what they are link here

Load Balancers – Scheduling Algorithms 

So how does a load balancer distribute the traffic and how does it decide which server to choose, the answer is it uses a load balancing algorithm.

I am going to briefly cover a few of the main ones below:

  • Round robin – requests are distributed across the group of server in a defined sequence
  • Least connections – the new request is sent to the server with the least connections the relative compute capacity is taken into consideration
  • Least time – a formula that combines least connections and fastest response time
  • Hash – based on a key that you define such as client ip address or request URL
  • Ip hash – the IP address of the client is used to determine which server receives the request
  • Random with two choices – picks two servers at random and sends the request to the one that is selected by then applying the least connections algorithm


AVI Networks was founded in 2012, it features the AVI Vantage Platform. So why is AVI different? AVI architecture separates the control or management plane from the data plane in order to create a centrally managed distributed fabric of application service delivery. As well as this AVI uses SEs (service engines) to continuously analyse data for application performance, security and end-user insights. The software can run on bare-metal servers, VMs and containers in private and public clouds as well as traditional data centres.


In 2019 Avi Networks was acquired by VMware, this was due to VMware’s expansion into their Virtual Cloud Vision. Avi Networks tied in brilliantly with one of VMware’s main product set, NSX. Therefore AVI was reborn as VMware NSX Advanced Load Balancer, striving to become a leader in modern load balancing.

What’s Next

Now that we’ve had a whistle stop tour of load balancers I think we need to delve a bit more into VMware’s NSX Advanced Load Balancer and understand how customers can use it to their advantage. Look out for my next post NSX Advanced Load Balancers-  The Journey.