mediumMultiple SelectObjective-mapped
350-401 Practice Question: Which two statements about MPLS Layer 3 VPNs are…
Which two statements about MPLS Layer 3 VPNs are true? (Choose two.)
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
✓
PE routers use MP-BGP to exchange customer VPN routes with other PE routers.
In MPLS Layer 3 VPNs, the provider edge routers participate in customer routing via MP-BGP, and the MPLS label stack includes both an outer transport label and an inner VPN label. The VPN label is used to identify the correct VRF and egress PE, not the ingress PE. The provider core routers do not need to know customer routes; they only switch based on the outer label. The VPN label is assigned by the egress PE, not the ingress PE.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
PE routers use MP-BGP to exchange customer VPN routes with other PE routers.
Why this is correct
Correct because MP-BGP is used to carry VPNv4 routes between PE routers, including the VPN label and route distinguisher.
- ✗
The MPLS label stack in an MPLS VPN packet contains only a single label that identifies the egress PE.
Why it's wrong here
Incorrect because the MPLS label stack typically contains two labels: an outer transport label (IGP label) and an inner VPN label.
- ✗
P routers must maintain a full routing table for all customer VPNs to forward traffic correctly.
Why it's wrong here
Incorrect because P routers only need to know how to reach PE loopbacks; they do not need customer VPN routes.
- ✗
The VPN label is assigned by the ingress PE and used by the egress PE to determine the outgoing interface.
Why it's wrong here
Incorrect because the VPN label is assigned by the egress PE and advertised via MP-BGP; the ingress PE pushes that label.
- ✓
The inner VPN label is used by the egress PE to forward the packet to the correct customer VRF.
Why this is correct
Correct because the egress PE pops the outer label and uses the inner VPN label to identify the VRF and forward the packet to the correct CE.
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Variation 1. Which two statements about MPLS Layer 3 VPNs are true? (Choose two.)
medium- ✓ A.PE routers use MP-BGP to exchange VPNv4 routes that include the route distinguisher and the VPN label.
- B.P routers in the MPLS core must maintain a full routing table for each customer VRF.
- C.CE routers must run MPLS and participate in the label distribution with the PE router.
- ✓ D.Each VRF on a PE router maintains a separate routing table and forwarding table per customer.
- E.The MPLS label stack in a Layer 3 VPN always contains exactly one label.
Why A: MPLS Layer 3 VPNs use MP-BGP to exchange VPNv4 routes between PE routers, and each VRF maintains a separate routing table per customer. The P routers do not need to know customer routes, and the CE router does not run MPLS. The label stack includes both an IGP label and a VPN label.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-401 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 350-401 exam.