|Round-Robin DNS load balancer||A DNS server with round-robin enabled will respond different IP addresses to requests.||Easy to implement.||1. Not evenly-distributed load balancing caused by client-side and DNS caching.|
2. Cannot be depended upon for site reliability.if one of the servers goes down, traffic will still be routed to this down server.
3. Does not account for server size, server load, transaction time, geographical distance, and other factors.
|L3/L4 load balancer||Traffic is routed by IP address and port. L3 is network layer (IP). L4 is session layer (TCP).||Better granularity, simple, responsive|
|L7 load balancer||Traffic is routed by what is inside the HTTP protocol.||Better granularity|
|Round Robin||Client requests are distributed to application servers in rotation.||simple||Does not take into consideration the characteristics of the application servers i.e. it assumes that all application servers are the same with the same availability, computing and load handling characteristics.|
|Weighted Round Robin||Weighted Round Robin builds on the simple Round-robin load balancing algorithm to account for differing application server characteristics.|
|Least Connection||Client requests are distributed to the application server with the least number of active connections at the time the client request is received.|
|Weighted Least Connection||Account for differing application server characteristics.|
|Resource Based (Adaptive)||Resource Based (Adaptive) is a load balancing algorithm requires an agent to be installed on the application server that reports on its current load to the load balancer.|
|Resource Based (SDN Adaptive)||SDN Adaptive is a load balancing algorithm that combines knowledge from Layers 2, 3, 4 and 7 and input from an SDN Controller to make more optimized traffic distribution decisions.|
|Fixed Weighting||Administrator assigns a weight to each application server based on criteria of their choosing to demonstrate the application servers traffic-handling capability.|
|Weighted Response Time||The response times of the application servers determines which application server receives the next request.||If a server fails and makes quick error response, it will attract more traffic and fails more.|
|Source IP Hash||combines source and destination IP addresses of the client and server to generate a unique hash key. The key is used to allocate the client to a particular server.|
|URL Hash||URL Hash is a load balancing algorithm to distribute writes evenly across multiple sites and sends all reads to the site owning the object.|