This page was exported from Free Cisco Training & Resources - Certification Exam Preparation [ https://www.ciscobibles.com ] Export date:Tue Mar 4 16:05:27 2025 / +0000 GMT ___________________________________________________ Title: CCNP BSCI Notes - OSPF Network Topologies --------------------------------------------------- OSPF Network Topology Options OSPF assumes a subnet is broadcast-capable by default. OSPF Network Types Broadcast multiaccess Point-to-point Point-to-multipoint broadcast Point-to-multipoint nonbroadcast Nonbroadcast multiaccess (NBMA) NBMA and point-to-multipoint are standards-compliant (RFC 2328), whereas point-to-multipoint nonbroadcast, broadcast, and point-to-point implementations are Cisco proprietary. NBMA networks utilize DRs like broadcast networks, however neighbors must be manually defined instead of being automatically discovered. Configuring OSPF in a Nonbroadcast Environment Nonbroadcast Network Because NBMA is the default network type for a nonbroadcast interface, the only necessary configuration is to define neighbors. DR priorities should be specified to ensure only candidates positioned well in the topology are elected DR and BDR. priority - This can be used to specify a higher priority than what has been configured on the neighbor (but not lower) poll interval - The rate at which hellos are sent to inactive neighbors (default 120 seconds) cost - Cost to reach the neighbor NBMA configuration: Point-to-multipoint Network Point-to-multipoint automatically establishes adjacencies along PVCs. Point-to-multipoint assumes broadcast capability by default; nonbroadcast can be specified, and neighbors must then be defined manually. Broadcast Network Point-to-point on Subinterfaces Router(config)# interface serial0 Router(config-if)# no ip address Router(config-if)# encapsulation frame-relay Router(config)# interface serial0.1 point-to-point Router(config-if)# ip address 10.1.1.1 255.255.255.0 Router(config-if)# frame-relay interface-dlci 51 Router(config)# interface serial0.2 point-to-point Router(config-if)# ip address 10.1.2.1 255.255.255.0 Router(config-if)# frame-relay interface-dlci 52 Router(config)# router ip ospf 1 Router(config-router)# network 10.1.1.1 0.0.0.255 area 0 --------------------------------------------------- Images: http://ciscobibles.com/wp-content/uploads/2010/01/CCNPBSCINotesOSPFNetworkTopologies_CB3E/clip_image002_thumb.jpg http://ciscobibles.com/wp-content/uploads/2010/01/CCNPBSCINotesOSPFNetworkTopologies_CB3E/clip_image004_thumb.gif http://ciscobibles.com/wp-content/uploads/2010/01/CCNPBSCINotesOSPFNetworkTopologies_CB3E/clip_image006_thumb.gif http://ciscobibles.com/wp-content/uploads/2010/01/CCNPBSCINotesOSPFNetworkTopologies_CB3E/clip_image008_thumb.gif http://ciscobibles.com/wp-content/uploads/2010/01/CCNPBSCINotesOSPFNetworkTopologies_CB3E/clip_image010_thumb.gif --------------------------------------------------- --------------------------------------------------- Post date: 2010-03-30 14:27:06 Post date GMT: 2010-03-30 06:27:06 Post modified date: 2010-07-23 00:37:36 Post modified date GMT: 2010-07-22 16:37:36 ____________________________________________________________________________________________ Export of Post and Page as text file has been powered by [ Universal Post Manager ] plugin from www.gconverters.com