Nokia Network Voyager for IPSO 4.0 Reference Guide 3519 Configuring RoutingThis chapter describes the IPSO routing subsystem, how to configure the various routingprotocols that are supported, route aggregation, and route redistribution.Routing OverviewThe Nokia routing subsystem, Ipsilon Scalable Routing Daemon (IPSRD), is an essential part ofyour firewall. IPSRD’s role is to dynamically compute paths or routes to remote networks.Routes are calculated by a routing protocol. IPSRD provides routing protocols, allows routes tobe converted or redistributed between routing protocols, and, when there are multiple protocolswith a route to a given destination, allows you to specify a ranking of protocols. Based on theranking, a single route is installed in the forwarding table for each destination.You can monitor routing by following links from Network Voyager. Another monitoring tool isICLID, which provides interactive, text-based monitoring of the routing subsystem.Routing ProtocolsRouting protocols compute the best route to each destination. Routing protocols also exchangeinformation with adjacent firewalls. The best route is determined by the cost or metric values.Routing protocols can be broken up into two major categories: exterior gateway protocols(EGPs) and interior gateway protocols (IGPs). Interior gateway protocols exchange routinginformation inside an autonomous system (AS). An AS is a routing domain, such as inside anorganization, that contacts its own routing. An EGP exchanges routing information betweenASes and provides for specialized policy-bound filtering and configuration.IPSRD supports three interior gateway protocols: RIP (Routing Information Protocol), IGRP(Interior Gateway Routing Protocol), and OSPF (Open Shortest Path First).Static routes and aggregate routes are also supported. For more information on static routes, see“Static Routes” on page 394. For more information on aggregate routes, see “RouteAggregation” on page 398.