mediumMultiple Select
300-410 Practice Question: Which TWO statements about MPLS label imposition…
Which TWO statements about MPLS label imposition (push) are true? (Choose TWO.)
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Label imposition occurs at the ingress LSR.
Label imposition occurs at the ingress LSR, which pushes a label onto an unlabeled IP packet. The label is based on the FEC (Forwarding Equivalence Class) derived from the IP destination. The egress LSR pops the label, not imposes it.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Label imposition occurs at the ingress LSR.
Why this is correct
Label imposition happens at the ingress label switching router, where the edge device classifies incoming packets and pushes the MPLS shim header before forwarding into the provider core. This satisfies the stem's requirement that push operations occur at the network edge, not on transit or egress routers deeper within the MPLS domain.
- ✗
Label imposition occurs at the egress LSR.
Why it's wrong here
Imposition pushes the label stack at the ingress LSR as packets enter the MPLS domain; the egress LSR performs disposition (pop) instead. It is tempting because egress nodes do handle label operations, but that is removal, not push.
- ✓
The imposed label is determined by the Forwarding Equivalence Class (FEC).
Why this is correct
The ingress LSR maps each incoming packet to a Forwarding Equivalence Class, and that FEC determines which label the LSR pushes onto the packet. Packets sharing a FEC receive identical forwarding treatment, so the imposed label reflects FEC membership.
- ✗
The imposed label is always the top label in a label stack.
Why it's wrong here
While the imposed label becomes the top label, this statement is not always true in all contexts (e.g., when pushing multiple labels). However, in basic MPLS, it is the top label, but the key point is that it is determined by FEC.
- ✗
Label imposition is performed using the 'tag-switching' command.
Why it's wrong here
Label imposition is configured with 'mpls ip' on the interface, not 'tag-switching', which is legacy Cisco terminology for enabling MPLS forwarding. It tempts because tag-switching commands did once control MPLS, but modern IOS uses mpls ip.
Go deeper
Related to this question
About these practice questions
One of 1,401 original 300-410 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 300-410 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 300-410 exam.