Basic OSPF Topology Configuration
Fixed Switch Configuration Guide 22-7
Router 1(su)->router(Config-if(Vlan 1))#ip ospf areaid 0.0.0.1
Router 1(su)->router(Config-if(Vlan 1))#ip ospf enable
Router 1(su)->router(Config-if(Vlan 1))#exit
Router 2 CLI Input
Router 2(su)->router(Config)#interface vlan 1
Router 2(su)->router(Config-if(Vlan 1))#ip ospf priority 10
Router 2(su)->router(Config-if(Vlan 1))#ip ospf areaid 0.0.0.1
Router 2(su)->router(Config-if(Vlan 1))#ip ospf enable
Router 2(su)->router(Config-if(Vlan 1))#exit
Router 3 CLI Input
Router 3(su)->router(Config)#interface vlan 1
Router 3(su)->router(Config-if(Vlan 1))#ip ospf priority 30
Router 3(su)->router(Config-if(Vlan 1))#ip ospf areaid 0.0.0.1
Router 3(su)->router(Config-if(Vlan 1))#ip ospf enable
Router 3(su)->router(Config-if(Vlan 1))#exit
Router 4 CLI Input
Router 4(su)->router(Config)#interface vlan 1
Router 4(su)->router(Config-if(Vlan 1))#ip ospf priority 0
Router 4(su)->router(Config-if(Vlan 1))#ip ospf areaid 0.0.0.1
Router 4(su)->router(Config-if(Vlan 1))#ip ospf enable
Router 4(su)->router(Config-if(Vlan 1))#exit
Configuring the Administrative Distance for OSPF Routes
If several routes coming from different protocols are presented to the fixed switch device, the
protocol with the lowest administrative distance will be chosen for route installation. By default,
OSPF administrative distance is set to 110. The distance ospf command in router configuration
mode can be used to change this value, resetting OSPF’s route preference in relation to other
routes as shown in the table below.
Configuring SPF Timers
In router configuration mode, use the timers spf command to fine-tune the operation of OSPF in
the network. You can change two timers with this command:
• The SPF delay, which is the delay in seconds between the receipt of an update and execution
of the shortest path first (SPF) calculation. The default delay is 5 seconds.
• The SPF hold time, which is the minimum amount of time, in seconds, between two
consecutive SPF calculations. The default value is 10 seconds, and valid values can range from
Route Source Default Distance
Connected 0
Static 1
OSPF Intra-area - 8; Inter-area - 10; External type 1 - 13; External type 2 - 150
RIP 15