350-501 Services Practice Question
A service provider is migrating from LDP to Segment Routing. What is the correct order of operations to ensure uninterrupted MPLS forwarding?
⚠ Common exam trap
Cisco often tests the misconception that you must disable the old protocol before enabling the new one, but the correct approach is to run both protocols in parallel to maintain forwarding continuity during migration.
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
✓
Enable SR on each router one by one while LDP remains active, then remove LDP after SR is stable.
It follows the recommended migration strategy of running LDP and Segment Routing (SR) in parallel. By enabling SR on each router one by one while LDP remains active, MPLS forwarding continues uninterrupted via LDP until SR is fully deployed and stable. Once SR is verified on all routers, LDP can be safely removed without causing any forwarding black holes.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Enable SR on each router one by one while LDP remains active, then remove LDP after SR is stable.
Why this is correct
Correct. This gradual migration ensures continuous forwarding via LDP while SR is established.
- ✗
Enable SR on all routers simultaneously.
Why it's wrong here
Incorrect. This can cause signaling mismatches and loss of connectivity.
- ✗
Configure IS-IS SR extensions on all routers, then disable LDP.
Why it's wrong here
Incorrect. Disabling LDP before SR is fully deployed will break MPLS forwarding.
- ✗
Disable LDP first to free labels, then enable SR.
Why it's wrong here
Incorrect. Disabling LDP first will remove all LDP labels, causing a forwarding outage.
Go deeper
Related to this question
About these practice questions
Courseiva writes every 350-501 question from scratch — 971 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.