350-501 Networking Practice Question
An engineer is configuring VPLS on a Cisco ASR 9000. After verifying the pseudowire status, they notice that the 'pw status' shows 'down' for one of the PWs. Which two conditions could cause this? (Choose two.)
⚠ Common exam trap
Cisco often tests the distinction between conditions that cause a pseudowire to be 'down' versus conditions that affect VPLS forwarding but leave the PW 'up', leading candidates to incorrectly select VPLS ID mismatch (Option B) as a cause of PW failure.
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
✓
Mismatched encapsulation type on the pseudowire (e.g., Ethernet vs. VLAN)
A mismatched encapsulation type (e.g., Ethernet vs. VLAN) on the pseudowire causes the PW to fail to come up. In VPLS, the encapsulation must match between the local and remote PE for the pseudowire to be operational; otherwise, the PW status will show 'down' due to a negotiation failure.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Mismatched encapsulation type on the pseudowire (e.g., Ethernet vs. VLAN)
Why this is correct
Encapsulation must match between peers.
- ✗
VPLS ID mismatch on the same bridge domain
Why it's wrong here
VPLS ID is local and not negotiated.
- ✗
SNMP MIB not loaded
Why it's wrong here
SNMP does not affect pseudowire status.
- ✓
MTU mismatch between local and remote PE
Why this is correct
MTU mismatch can cause pseudowire to go down.
- ✗
LDP session is missing
Why it's wrong here
LDP session is required for signaling; if missing, PW would not come up, but not directly causing 'down' status as described.
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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.