Juniper JN0-360 OSPF RID Calculation
Question
-- Exhibit --
interfaces {
ge-1/0/3 {
unit 0 {
family inet {
address 192.168.1.1/30;
}
}
}
ge-1/1/0 {
unit 0 {
family inet {
address 10.100.10.1/30;
}
}
}
fxp0 {
unit 0 {
family inet {
address 10.2.1.13/28;
}
}
}
lo0 {
unit 0 {
family inet {
address 10.100.1.1/32;
address 127.0.0.1/32;
}
}
}
}
protocols {
ospf {
area 0.0.0.0 {
interface ge-1/0/3.0;
interface ge-1/1/0.0;
}
}
}
-- Exhibit --
Click the Exhibit button.
The router was just powered on.
Referring to the exhibit, what is the OSPF RID?
Answers
Explanations
Click on the arrows to vote for the correct answer
A. B. C. D.B
In the given exhibit, there are four interfaces defined with IP addresses and one OSPF protocol defined with two interfaces added under area 0.0.0.0.
OSPF RID (Router ID) is the unique identifier assigned to each router running OSPF in a network. It is used to identify the router in OSPF protocol updates and is used to elect the designated router (DR) and backup designated router (BDR) in multi-access networks.
In the given exhibit, the router has not been explicitly configured with a RID, so it will automatically choose a RID based on the following criteria in the given order:
- The highest IP address assigned to a loopback interface.
- The highest IP address assigned to a non-loopback interface.
- The router ID specified using the router-id configuration statement.
As per the exhibit, the router has one loopback interface lo0, which has two IP addresses configured, 10.100.1.1/32 and 127.0.0.1/32. Therefore, the router will choose 10.100.1.1 as its OSPF RID since it has the highest IP address among all the configured addresses on the router.
Therefore, the answer is option B, 10.100.1.1.
