-- Exhibit --
user@R1> show
interfaces {
ge-1/1/0 {
unit 0 {
family inet {
address 10.100.1.1/30;
}
family iso;
}
}
lo0 {
unit 0 {
family inet {
address 10.100.10.1/32;
}
family iso {
address 49.1001.0010.0100.00;
}
}
}
}
protocols {
isis {
level 1 disable;
interface ge-1/1/0.0 {
level 2 disable;
}
interface lo0.0;
}
}
user@R2> show
interfaces {
ge-1/1/0 {
unit 0 {
family inet {
address 10.100.1.2/30;
}
family iso {
mtu 1496;
}
}
}
lo0 {
unit 0 {
family inet {
address 10.100.10.2/32;
}
family iso {
address 49.1002.0010.0200.00;
}
}
}
}
protocols {
isis {
interface ge-1/1/0.0 {
level 2 disable;
}
interface lo0.0;
}
}
-- Exhibit --
Click the Exhibit button.
Referring to the exhibit, R1 and R2 are directly connected using interface ge-1/1/0.
What is the reason the IS-IS adjacency fails?
Click on the arrows to vote for the correct answer
A. B. C. D.B
Referring to the exhibit, there are two Juniper routers, R1 and R2, connected via interface ge-1/1/0. The exhibit shows the configuration of both routers.
The IS-IS protocol is a link-state protocol used for routing in IP and OSI networks. In this case, both routers are running IS-IS, and there is a problem with the adjacency between them. The question asks for the reason why the adjacency fails.
Looking at the configuration, we see that R1 has the following IS-IS configuration:
kotlinprotocols { isis { level 1 disable; interface ge-1/1/0.0 { level 2 disable; } interface lo0.0; } } This configuration disables IS-IS for Level 1 and Level 2 on interface ge-1/1/0.0. On the other hand, R2 has the following IS-IS configuration:
kotlinprotocols { isis { interface ge-1/1/0.0 { level 2 disable; } interface lo0.0; } } This configuration disables IS-IS for Level 2 only on interface ge-1/1/0.0.
Therefore, the reason the IS-IS adjacency fails is that R1 has IS-IS disabled for both Level 1 and Level 2 on interface ge-1/1/0.0, while R2 only has IS-IS disabled for Level 2 on the same interface. Since IS-IS is disabled for Level 2 on R2, it expects to form an adjacency with another Level 2 router, which R1 is not.
To fix this problem, the IS-IS configuration on R1 should be updated to enable IS-IS for Level 2 on interface ge-1/1/0.0, or the IS-IS configuration on R2 should be updated to disable IS-IS for Level 2 on interface ge-1/1/0.0.