1. Packet Types
   1. HELLO
   2. Database Description (DBD)
   3. Link-State Request (LSR)
   4. Link-State Update (LSU)
   5. Link-State Ack (LSAck)
2. History
   1. 1987 - OSPF Group
   2. 1991 - OSPFv2 (RFC 1247)
   3. 1998 - OSPFv2 (RFC 2328)
   4. 1999 - OSPFv3 (RFC 2740) for IPv6
3. Basic Config
   1. R1(config)#router ospf process-id
   2. R1(config-router)#network network-address wildcard-mask area area-id
   3. R1(config-router)#router-id ip-address
      1. if none - highest IP of Loopback interfaces
      2. if none - highest IP of any physical interfaces
      3. to modify router-id
         1. reload
         2. clear ip ospf process
   4. R1(config-router)#default information originate
   5. R1(config-router)#auto-cost reference-bandwidth {1-4294967}
   6. R1(config-if)#router ospf priority {0-255}
   7. R1(config-if)#ip ospf cost
   8. R1(config-if)#ip ospf hello-interval seconds
   9. R1(config-if)#ip ospf dead-interval seconds
   10. Troubleshooting
       1. R1#show ip ospf neighbor
       2. R1#show ip protocols
       3. R1#show ip ospf
       4. R1#show ip ospf interface
4. Algorhytm
   1. LSDB
   2. SPF Algorhitm
   3. SPF Tree
   4. Routing Table
5. Intervals
   1. HELLO
      1. MA & P2P - 10 sec
      2. NBMA - 30 sec
   2. DEAD
      1. MA & P2P - 40 sec
      2. NBMA - 120 sec
6. Metric
   1. FE & Faster = 1
   2. Ethernet = 10
   3. E1 = 48
   4. T1 = 64
   5. 128 kbps = 781
   6. 64 kbps = 1562
   7. 56 kbps = 1785
7. IP
   1. 224.0.0.5 - All OSPF Routers
   2. 224.0.0.6 - All DR
8. DR & BDR Election
   1. DR - router with highest ospf priority
   2. BDR - router with a second highest ospf priority
   3. if prioritys are equal - roiter-id is used
   4. All another routers - DROther