Exam JN0-363 topic 1 question 53 discussion

C - install statement allows you to associate one or more prefixes with an LSP. It cannot be B (explicit-null) because explicit-null is specifically targeted to the egress router for label removal (as opposed to the penultimate router) and for QoS value checking by the core network.

B - The explicit-null label ensures that an MPLS header is retained in packets when they are forwarded through the label-switched path (LSP). It allows downstream devices to recognize the MPLS labels and forward traffic accordingly. This ensures that all devices within the LSP use the MPLS labels for traffic forwarding.

he "install" command associates one or more IP prefixes with a Label Switched Path (LSP), effectively adding those prefixes to the routing table (inet.3 or inet6.3) once the LSP is active, allowing traffic destined for those prefixes to be routed through the MPLS tunnel established by the LSP; essentially, it "installs" the route for the specified prefixes within the MPLS context

explicit-null applied on egress router under protocol mpls ultimate-hop-popping on ingress router (R1) under lsp configuration

I think A is the correct Answer

B is corret.

I agree with lukaspi

The question is about penultimate-hop-popping and implicit and explicit null labels.

https://www.juniper.net/documentation/us/en/software/junos/mpls/topics/ref/statement/install-edit-protocols-mpls.html

Correct answer is C

https://www.juniper.net/documentation/us/en/software/junos/mpls/topics/ref/statement/install-edit-protocols-mpls.html