In version 2 of the LBaaS API, the following load balancing algorithms can be applied to a pool:

• Round robin
• Least connections
• Source IP

With the round robin algorithm, the load balancer passes each new connection to the next server in line. Over time, all connections will be distributed evenly across all machines being load balanced. Round robin is the least resource-intensive algorithm and has no mechanism to determine when a machine is being overwhelmed by connections. To avoid overwhelming a pool member, all members should be equal in terms of processing speed, connection speed, and memory.

With the least connections algorithm, the load balancer passes a new connection to a server that has the least number of current connections. It is considered a dynamic algorithm, as the system keeps track of the number of connections attached to each server and balances traffic accordingly. Pool members of higher capabilities will likely receive more traffic, as they are able to process connections quicker.

With the source IP algorithm, all connections originating from the same source IP address are sent to the same pool member. Connections are initially balanced using the round robin algorithm and are then tracked in a table for future lookup with subsequent connections from the same IP address. This algorithm is useful in cases where the application requires clients to persist to a particular server for all requests, such as an online shopping cart that stores session information on the local web server.