Chapter 11 IPsec VPN for FortiOS 5.0 : Hub-and-spoke configurations : Configure the hub : Configuring communication between spokes (policy-based VPN)
  
Configuring communication between spokes (policy-based VPN)
For a policy-based hub-and-spoke VPN, you define a concentrator to enable communication between the spokes.
To define the VPN concentrator
1. At the hub, go to VPN > IPSEC > Concentrator and select Create New.
2. In the Concentrator Name field, type a name to identify the concentrator.
3. From the Available Tunnels list, select a VPN tunnel and then select the right-pointing arrow.
4. Repeat Step 3 until all of the tunnels associated with the spokes are included in the concentrator.
5. Select OK.