A site-to-site VPN that allows you to connect two or more sites separated by a wide area network (WAN) such that they appear to be on a single private network. The following figure shows a site connected by a tunnel.

The following figure shows how the Vyatta router supports IPsec-protected site-to-site tunnels.

For site-to-site IPsec tunnels, the Vyatta router supports a special kind of interface—a virtual tunnel interface—that provides a routable interface at the endpoints of the tunnel.

For information about site-to-site VPN deployment and virtual tunnel interfaces, see Ciena Vyatta Network OS IPsec Site-to-Site VPN Configuration Guide.