Fortinet FortiGate 4000 Benutzerhandbuch

In a hub-and-spoke network, all VPN tunnels terminate at a single VPN peer called a 
hub. The peers that connect to the hub are known as spokes. The hub functions as a 
concentrator on the network, managing the VPN connections between the spokes.

The advantage of a hub-and-spoke network is that the spokes are simpler to configure 
because they require fewer policy rules. Also, a hub-and-spoke network provides 
some processing efficiencies, particularly on the spokes. The disadvantage of a hub-
and-spoke network is its reliance on a single peer to handle management of all VPNs. 
If this peer fails, encrypted communication in the network is impossible.

A hub-and-spoke VPN network requires a special configuration. Setup varies 
depending on the role of the VPN peer.

If the VPN peer is a FortiGate unit functioning as the hub, or concentrator, it requires a 
VPN configuration connecting it to each spoke (AutoIKE phase 1 and 2 settings or 
manual key settings, plus encrypt policies). It also requires a concentrator 
configuration that groups the hub-and-spoke tunnels together. The concentrator 
configuration defines the FortiGate unit as the hub in a hub-and-spoke network.