102OSPF can work normally only after being enabled on a router, regardless of the router’s type. Onan OSPF-enabled router, use the default values of parameters, such as the transmit interval ofOSPF packets, LSA delay timer, and SPF calculation interval, or configure them as required.Network planning is needed before OSPF configuration on routers. The configurations for routersin an area are performed on the area basis. Wrong configurations may cause communicationfailures, even routing information blocks, or routing loops between neighboring routers.Enabling OSPFYou must enable OSPF before you can perform other OSPF configuration tasks.PrerequisitesBefore configuring OSPF, you must configure the link layer protocol and IP addresses forinterfaces, making neighboring nodes accessible with each other at the network layer.Configuration procedureTo enable OSPF on a router, create an OSPF process and specify areas with which the process isassociated, and the network segments contained in each area. If an interface’s IP address resideson a network segment of an area, the interface belongs to the area and is enabled with OSPF,and OSPF advertises the direct route of the interface.To run OSPF, a router must have a Router ID, which is the unique identifier of the router in the AS.Following is additional information about Router IDs:• You can specify a Router ID when creating the OSPF process. Any two routers in an AS musthave different Router IDs. In practice, the ID of a router is the IP address of one of itsinterfaces.• If you specify no Router ID when creating the OSPF process, the global Router ID will beused. For details about a global Router ID, see IP Routing Basics in the Layer 3 – IP RoutingConfiguration Guide. H3C rec specifying a Router ID when creating the OSPF process.The system supports OSPF multiprocess and OSPF multi-instance as follows:• When a router runs multiple OSPF processes, specify a Router ID for each process, whichtakes effect locally and has no influence on packet exchange between routers. This meansthat two routers with different process IDs can exchange packets.• You can configure an OSPF process to run in a specified VPN instance.To do… Use the command… RemarksStep 1 Enter system view System-view —
