Implementing & verification OSPF

Configuring OSPF in a Single Area

Necessary information:

• OSPF process ID (locally significant)
• Participating interfaces
• Area ID
• Router ID

Enable OSPF

Router(config)# router ospf 

Configure Included Networks

Router(config-router)# network   area

A single interface can be specified by supplying its IP address and a null wildcard mask:

network 192.168.0.1 0.0.0.0 area 0

Router ID

If no router ID has been administratively declared, a router will choose the highest loopback IP address. If no loopback addresses are present, the highest IP address of the first active interface will be used.

A router ID can be manually specified:

Router(config-router)# router-id 

Best practice dictates the creation of a loopback address to be used as the router ID for stability and continuity:

Router(config)# interface loopback 0
Router(config-if)# ip address  

Default Cost

Link cost is a 16-bit value (0-65535); default cost is calculated as 100Mbps/interface bandwidth. (Interfaces 100Mbps and faster are assigned a cost of 1.)

OSPF cost can be manually specified per interface:

Router(config-if)# ip ospf cost 

An alternative to defining static costs per interface is to change the numerator bandwidth (default 100Mbps):

Router(config-router)# ospf auto-cost reference-bandwidth 

Reference speed is a 32-bit value (1 - 4294967). If reference speed is modified, the same modification should be performed on all routers within the area.

Router Priority

Default DR election priority is 1, and a router with a priority of 0 will not become a DR. Priority range is 0 - 255.

Router(config-if)# ip ospf priority 

Verifying OSPF Configuration

• show ip ospf - OSPF process details

• show ip ospf database - Contents of the topology database

• show ip ospf interface - Interfaces participating in OSPF

• show ip ospf neighbor - Neighbor information

• show ip protocols - Displays all active routing protocols

• show ip route

• debug ip ospf events

• debug ip packet

!! В дебаге роутер определяется router-id !!



# clear ip ospf process