A server load balancer (SLB) is another device that is used to provide redundancy for the application in case the physical or virtual servers go down. A server load balancer is a device that abstracts the actual server pool that runs an application and provides a single logical view of the entire pool to the end users. Note that a basic form of load balancing can also be done using Domain Name Service (DNS) by resolving the same host to multiple IP addresses at the DNS server.
There are multiple types of SLBs, such as application SLBs and transport SLBs. We will focus on the transport SLBs in this section. A sample deployment using transport SLBs is depicted in the following figure: