Topology

Topology: five-routers-five-pcs

Open Shortest Path First

• Link-State Vector
  • takes “cost” of links into account
  • not just “distance”, like RIP
• Forms neighbour relationships
  • negotiates and compares parameters with peers
    • eg timer values must match
    • subnet configuration must match
• Has a concept of “Router-ID”
  • 32-bit number, expressed as a dotted quad
    • eg 1.1.1.1
    • copied from the loopback interface with the highest IP address
    • or specified manually
• Supports areas, for scaling large networks
  • we will all use area 0

Configuration

r7#configure
r7(config)#router ospf 100   <- process ID
r7(config-router-ospf)#network 10.0.0.0/24 area 0
r7(config-router-ospf)#network 192.168.x.0/24 area 0
r7(config-router-ospf)#end
r7#show ip ospf interface brief
...
r7#show ip ospf neighbor
...

Setting an OSPF router ID

r7#configure
r7(config)#interface loopback 1
r7(config-if-Lo1)#ip address 7.7.7.7/32
r7(config-if-Lo1)#ospf network point-to-point
r7(config-if-Lo1)#ip ospf 100 area 0
r7(config-if-Lo1)#end
r7#show ip ospf interface brief
...
r7#show ip ospf ?
...

Investigate OSPF!

r7#show ip ospf summary
r7#show ip ospf neighbor
r7#show ip ospf database
r7#show ip ospf interface brief
r7#show ip route
r7#show ip ospf