The correct answer is that the headend will impose a label stack containing labels 16000, 16001, and 16002. This is because an SR-TE policy with an explicit segment-list defines a strict, predetermined path using MPLS prefix-SIDs assigned to specific nodes, and the headend router must push the entire label stack in order to enforce that exact path without relying on dynamic computation or LDP. On the Cisco SPCOR 350-501 exam, this concept tests your understanding of how explicit segment-lists differ from dynamic paths, and a common trap is assuming the headend only pushes a single label or that intermediate routers perform label swapping. Remember the key distinction: with an explicit segment-list, the headend is responsible for imposing the full ordered stack, so think “explicit equals full stack push.” A useful memory tip is “Explicit = Entire stack imposed at entry.”
350-501 MPLS and Segment Routing Practice Question
This 350-501 practice question tests your understanding of mpls and segment routing. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Exhibit
segment-routing traffic-engineering
policy POLICY1
color 100 end-point 192.0.2.1
candidate-path path1
preference 50
explicit segment-list SEG1
!
segment-list SEG1
index 10 mpls label 16000
index 20 mpls label 16001
index 30 mpls label 16002
!
Refer to the exhibit. An operator configures an SR-TE policy on a headend router. Which statement is true about the traffic steered into this policy?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The headend will impose a label stack containing labels 16000, 16001, and 16002
The correct answer is D because the SR-TE policy uses a segment-list with three labels (16000, 16001, 16002), which are MPLS labels assigned to prefix-SIDs for specific nodes. The headend imposes this label stack to steer traffic along the explicit path defined by the segment-list, ensuring strict source routing without relying on dynamic CSPF computation or LDP.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The segment-list consists of adjacency-SIDs
Why it's wrong here
Labels 16000,16001,16002 are typical prefix-SIDs.
✗
The path is automatically computed using CSPF based on IGP metrics
Why it's wrong here
The path is explicitly defined via segment-list.
✗
Traffic is forwarded using MPLS LDP labels
Why it's wrong here
SR-TE does not use LDP; it uses SR labels.
✓
The headend will impose a label stack containing labels 16000, 16001, and 16002
Why this is correct
Explicit segment-lists define the ordered list of labels.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distinction between explicit segment-lists (which require manual label configuration) and dynamic path computation (CSPF), leading candidates to mistakenly assume CSPF is always used in SR-TE policies.
Detailed technical explanation
How to think about this question
In SR-TE, the segment-list defines an ordered list of MPLS labels (prefix-SIDs or adjacency-SIDs) that the headend pushes onto the packet. The label stack 16000, 16001, 16002 corresponds to prefix-SIDs of intermediate nodes, and each router along the path pops its own label and forwards based on the next label, enabling strict traffic engineering without per-flow state in transit routers. This is defined in RFC 8402 and commonly configured via the 'segment-routing traffic-engineering' policy under Cisco IOS XR.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A network engineer at a university connects two campus buildings via a fibre link. Both routers run OSPF, but no adjacency forms — even though both routers can ping each other. The engineer finds one router is in area 0 and the other in area 1. OSPF adjacency requires matching area numbers, hello/dead timers, and network type. IP reachability alone is not enough.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
MPLS and Segment Routing — This question tests MPLS and Segment Routing — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The headend will impose a label stack containing labels 16000, 16001, and 16002 — The correct answer is D because the SR-TE policy uses a segment-list with three labels (16000, 16001, 16002), which are MPLS labels assigned to prefix-SIDs for specific nodes. The headend imposes this label stack to steer traffic along the explicit path defined by the segment-list, ensuring strict source routing without relying on dynamic CSPF computation or LDP.
What should I do if I get this 350-501 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This 350-501 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 350-501 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.