Topology for multiple networks
As shown in below, you can create multiple WAN optimization configurations between many private networks. Whenever WAN optimization occurs, it is always between two FortiGate units, but you can configure any FortiGate unit to perform WAN optimization with any of the other FortiGate units that are part of your WAN.
WAN optimization among multiple networks
You can also configure WAN optimization between FortiGate units with different roles on the WAN. FortiGate units configured as security devices and for WAN optimization can perform WAN optimization as if they are single-purpose FortiGate units just configured for WAN optimization.
WAN optimization with web caching
You can add web caching to a WAN optimization topology when users on a private network communicate with web servers located across the WAN on another private network.
WAN optimization with web caching topology
The topology above is the same as that shown in Basic WAN optimization topology on page 2836 with the addition of web caching to the FortiGate unit in front of the private network that includes the web servers. You can also add web caching to the FortiGate unit that is protecting the private network. In a similar way, you can add web caching to any WAN Optimization topology.