350-501 Services Practice Question
Which THREE components are required to deploy MPLS Layer 3 VPN?
⚠ Common exam trap
Cisco often tests the misconception that an IGP like OSPF is mandatory for MPLS Layer 3 VPN, when in fact the required components are VRFs, LDP (or another label distribution protocol), and MP-BGP with VPNv4 address family—the IGP is only needed to support LDP, not as a direct component of the VPN service.
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
✓
VRFs on PE routers
VRFs (Virtual Routing and Forwarding) are required on PE routers to maintain separate, isolated routing tables for each customer VPN. This allows overlapping IP addresses between different customers and ensures that traffic from one VPN does not leak into another. Without VRFs, the PE router cannot distinguish between customer routes, making Layer 3 VPN operation impossible.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
VRFs on PE routers
Why this is correct
VRFs provide per-customer routing separation.
- ✗
GRE tunneling
Why it's wrong here
GRE tunneling is not required; MPLS encapsulation is used.
- ✗
OSPF
Why it's wrong here
Any IGP (OSPF, IS-IS) can be used; not specifically required.
- ✓
LDP
Why this is correct
LDP distributes labels for MPLS forwarding.
- ✓
MP-BGP with VPNv4 address family
Why this is correct
MP-BGP carries VPN routes between PEs.
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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.