What Will An Ospf Router Prefer To Use First As A Router Id?

What will an OSPF router prefer to use first as a router ID?

• A loopback interface because it is configured with the high IP address on the router.
• The interface IP is highly active and is configured on the router.
• The IP address which configured with the command router-id.
• Right before the specific configuration, the interface participates in the routing process is the preference of the ODPF.

Answer: The preference for the OSPF router ID is the 32-bit address and is not present in the routing table and is not taken into account by any network command. If the OSPF router ID is not used for the configuration with the router-id command then the loopback interface. if these options are not available then the OSPF router uses the IP address from the physical interface.

What is OSPF?

The first open part is the IP protocol to functions such as IGP (Inner Gateway Protocol of internet and work in the IP address distribution over the autonomous system in the network. OSPF is also the link-state routing protocol and shares the information related to the network with the neighboring networks. The information is all over the AS that’s why every router in the AS has the provided information. With the help of the Dijkstra algorithm, the information determined the end-to-end path .that is the reason that is link-state the next-hop address which is the destination for the data is identified by selecting the best end-to-end path.

The main pros of the link state that the information which is spread throughout the AS helps the router to determine the routes his meets their criteria and is effective for traffic engineering, where the router meets the specific quality of the required services. While the protocol will not hold more routes as they continue to add. Greater the routs then increase in length, frequency, and the time to find the end-to-end routes. It means the link protocol is not suitable for the internet in a wide area and the IGPS work with a single AS due to this reason.

Configuration of the OSPF

Suppose if we have three router names with R1, R2, R3, and they are associated with the network 10.255.255.80/30, 192.168.10.48/29, and 10.255.255.8/30 (interface gi0/0).

 R1 configuration are in the following:

R1(config)#router ospf 1

R1(config-router)#network 192.168.10.48 0.0.0.7 area 1

R1(config-router)#network 10.255.255.80 0.0.0.3 area 1

R1(config-router)#network 10.255.255.8 0.0.0.3 area 1.

Configuring of the R2 in OSPF

R2 (config)#router ospf 1

R2 (config-router)#network 192.168.10.64 0.0.0.7 area 1

R2 (config-router)#network 10.255.255.80 0.0.0.3 area 1

Now for the R3 configuration

R3 (config)#router ospf 1

R3 (config-router)#network 192.168.10.16 0.0.0.7 area 1

R3 (config-router)#network 10.255.255.8 0.0.0.3 area 1

The configuration is checked with the command in the following:

R3#show ip protocols