Voyager Reference Guide 17VPN (Virtual Private Networking) TunnelsVPN tunnels encapsulate IP packets using Generic Routing Encapsulation(GRE) without options. The encapsulated packets appear as unicast IPpackets. For each VPN tunnel you create, you must assign a local and remoteIP address. You also must provide the local and remote endpoint addresses ofthe interface to which this tunnel is bound. VPN tunnels provide redundantconfiguration between two sites for high availability. The remote router mustalso support VPN encapsulation and must be configured with a tunnelinterface to the local router.Routing OverviewThis section discusses the following topics:! Nokia Routing Subsystem! Routing ProtocolsNokia Routing SubsystemThe Nokia routing subsystem, Ipsilon Routing Daemon (IPSRD), is anessential part of your firewall. IPSRD’s role is to dynamically compute pathsor routes to remote networks. Routes are calculated by a routing protocol.Besides providing routing protocols, IPSRD also allows routes to beconverted or redistributed between routing protocols. Finally, when there aremultiple protocols with a route to a given destination, IPSRD allows you tospecify a ranking of protocols. Based on this ranking, a single route isinstalled in the forwarding table for each destination.You can configure each of the supported routing protocols, routeredistribution, and other routing options via the Configuring Routing sectionin Voyager.Routing monitoring is available by following links from the individualprotocol pages or by clicking on the Monitor button in Voyager. Another
