Configuring OSPF Network Types 941n ■ It is required to use the stub command on routers attached to a stub area.■ It is required to use the nssa command on routers attached to an NSSA area.■ Using the default-cost command only takes effect on the ABR of a stub areaor the ABR/ASBR of an NSSA area.Configuring OSPFNetwork TypesOSPF classifies networks into four types upon link layer protocols. Since an NBMAnetwork must be fully meshed, namely, any two routers in the network must havea virtual link in between. In most cases, however, the requirement cannot besatisfied, so you need to change the network type using commands.For routers having no direct link in between, you can configure related interfacesas the P2MP mode. If a router in the NBMA network has only a single peer, youcan also configure associated interfaces as the P2P mode.In addition, when configuring broadcast and NBMA networks, you can specify forinterfaces router priorities for DR/BDR election. In practice, routers having higherreliability should become the DR/BDR.Prerequisites Before configuring OSPF network types, you have configured:■ IP addresses for interfaces, making neighboring nodes accessible with eachother at network layer.■ OSPF basic functionsConfiguring the OSPFNetwork Type for anInterfaceFollow these steps to configure the OSPF network type for an interface:n ■ Configuring a new network type for an interface overwrites the previousnetwork one (if any).Create and configure a virtuallinkvlink-peer router-id [ helloseconds | retransmit seconds| trans-delay seconds | deadseconds | simple [ plain |cipher ] password | { md5 |hmac-md5 } key-id [ plain |cipher ] password ] *OptionalConfigured on both ends of avirtual linkNote that hello and deadparameters must be identicalon both ends of the linkConfigure and advertise ahost routehost-advertise ip-addresscostOptionalNot advertised by defaultTo do... Use the command... RemarksTo do... Use the command... RemarksEnter system view system-view -Enter interface view interface interface-typeinterface-number-Configure the networktypeospf network-type{ broadcast | nbma | p2mp |p2p }OptionalNot configured by defaultThe network type of an interfacedepends on the media type ofthe interface
