The LoadMaster makes a differentiation between L4 and L7 handling. This refers to Layer 4 and Layer 7 of the OSI model. Layer 4 involves TCP/UDP ports, and Layer 7 refers to the higher-level awareness of the LoadMaster, such as with HTTP cookies, SSL acceleration, and content switching. For all Layer 4 Virtual Services, the only behaviour available is transparent networking.

Layer 4 is any load balanced traffic that does not involve cookie persistence, SSL acceleration, content switching or content switching rules. Layer 4 does include SRC (source IP) address persistence.

It is possible to tell if a Virtual Service is using L4 or L7 handling by looking at the Virtual Service in Virtual Services and View/Modify Services in the main menu of the LoadMaster Web User Interface (WUI). It will indicate what layer it is operating on in the Layer column.

Any time any cookie persistence, SSL acceleration, or content switching options are used, the traffic automatically becomes L7.