350-501 Networking Practice Question
An ISP is designing a new core network using MPLS-TE. They require very fast failure detection for link and node failures to minimize traffic loss. Which two technologies should they combine? (Choose two.)
⚠ Common exam trap
Cisco often tests the misconception that OSPF or IS-IS fast hello timers alone can achieve sub-second failure detection, but BFD is required for truly fast detection independent of routing protocol convergence.
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
✓
MPLS-TE Fast Reroute (FRR)
MPLS-TE Fast Reroute (FRR) provides sub-50 ms protection switching by pre-computing backup paths (bypass tunnels) for link and node failures, ensuring minimal traffic loss. Bidirectional Forwarding Detection (BFD) provides sub-second failure detection by sending rapid, lightweight hello packets independent of routing protocols, enabling faster convergence when combined with FRR.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
OSPF with hello timers set to 1 second
Why it's wrong here
Even with fast hello, OSPF convergence is slower than BFD+FRR.
- ✓
MPLS-TE Fast Reroute (FRR)
Why this is correct
Provides local repair via backup tunnels.
- ✓
Bidirectional Forwarding Detection (BFD)
Why this is correct
Provides fast hello detection.
- ✗
LSP Ping and Traceroute
Why it's wrong here
Used for fault detection and isolation, not for fast protection.
- ✗
Label Distribution Protocol (LDP)
Why it's wrong here
LDP does not provide fast failure detection.
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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.