11.2.4 OSPF router id
	* defined by router-id command
	* highest loopback address
	* highest active physical address
11.2.5 OSPF adjacency requirement
11.3.1 OSPF Metric  ==> cost = 10^8/bandwidth
11.3.2 modifying cost  (bandwidth or ip ospf cost)
11.4.1 five link types
11.4.2 DR/BDR election
11.4.3 ip ospf priority
11.5.2 set intervals