350-501 EVPN-VPWS Practice Question
A service provider is deploying EVPN-VPWS for point-to-point services. They have set up an EVPN instance with Ethernet Segment Identifier (ESI) and EVI. After configuration, the pseudowire is not coming up. Which misconfiguration is most likely?
⚠ Common exam trap
Candidates may mistakenly think that the EVI must be unique per PE, but in EVPN-VPWS the EVI must match across PEs for the same service. The real misconfiguration is often forgetting to activate the BGP EVPN address-family.
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
✓
The BGP EVPN address-family is not activated.
In EVPN-VPWS, the EVI (EVPN Instance) must be the same on both PEs for the same point-to-point service to ensure proper route matching and label assignment. Therefore, using the same EVI is correct and not a misconfiguration. The most likely issue is that the BGP EVPN address-family is not activated on the PEs. Without this address-family, the PEs cannot exchange EVPN routes (e.g., Type 1 per-EVI AD routes), so the pseudowire cannot be established. The other options—ESI all-zeros (acceptable for single-homed) and MTU mismatch (would cause operational issues but not prevent pseudowire from coming up at the control-plane level)—are less likely to be the root cause.
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 same EVI is used on both PEs.
Why it's wrong here
Incorrect. In EVPN-VPWS, the EVI must be the same on both PEs for the same service to ensure correct route matching and label assignment. Using the same EVI is standard and not a misconfiguration.
- ✗
The ESI is all-zeros.
Why it's wrong here
Incorrect. An all-zeros ESI is allowed for single-homed connections and would not prevent the pseudowire from coming up.
- ✗
The MTU mismatch on the attachment circuits.
Why it's wrong here
Incorrect. MTU mismatch on attachment circuits can cause operational issues but typically does not prevent the pseudowire control plane from coming up.
- ✓
The BGP EVPN address-family is not activated.
Why this is correct
Correct. The BGP EVPN address-family must be activated on both PEs to exchange EVPN routes. Without it, the PEs cannot advertise or receive the necessary per-EVI AD routes, and the pseudowire will not be established.
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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.