Chapter 6

"Do I Know This Already?"

5.A and D
10.A and C


Router(config-if)#ip ospf network point-to-multipoint broadcast

The broadcast option is a default, not a keyword option.

2.The ip ospf priority number command is used to determine the DR manually. The higher the priority is, the greater the likelihood of success.
3.It is necessary to have one subnet per connection. Thus, if there are four point-to-point links, four subnets are required.
4.The ip ospf network point-to-multipoint non-broadcast command was introduced with Cisco IOS Release 11.3a. You can find more information online at by searching for "OSPF point-to-multipoint network with separate costs per neighbor." This feature was added to support customers using point-to-multipoint on nonbroadcast media, such as classic IP over ATM.
5.The syntax of the neighbor command is
Router(config-if)#neighbor ip-address [priority number ] [poll-interval sec]


6.Multiaccess topologies, such as those found in NBMA and broadcast OSPF network types, rely on DRs and so are best applied to full-mesh topologies. If the topology is not a full mesh, then the DR should be manually selected, using priorities, to be a router with permanent virtual circuits (PVCs) connecting to all other routers.
7.4—30/120 (NBMA, point-to-multipoint) or 10/40 (broadcast and point-to-point)
8.The configuration options proprietary to Cisco for NBMA are
  • Point-to-multipoint nonbroadcast

  • Broadcast

  • Point-to-point

9.In a point-to-point network, the concept of multicast is not relevant because the communication is direct to another router. There is very little network overhead. An IP subnet is required for each point-to point link.

With multipoint interfaces, OSPF network traffic is replicated and sent down each PVC.

10.The default OSPF network type for serial interfaces is nonbroadcast multiaccess.