300-410 Layer 3 Technologies Practice Question
A network engineer is configuring MPLS Layer 3 VPN on a Cisco IOS XE router. The engineer needs to enable the provider edge (PE) router to exchange VPNv4 routes with another PE router. Which address family must be configured under the BGP routing process to achieve this?
⚠ Common exam trap
Many candidates confuse the VPNv4 address family with the IPv4 VRF address family, which is used for PE-CE routing.
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
✓
address-family vpnv4 unicast
To exchange VPNv4 routes between PE routers in an MPLS L3VPN environment, the BGP process must be configured with the address-family vpnv4 unicast command. This enables the PE routers to exchange VPNv4 prefixes along with MPLS labels and route targets. The other address families do not support VPNv4 route exchange.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
address-family ipv4 vrf
Why it's wrong here
This address family is used within a VRF context to exchange IPv4 routes for a specific VRF. It is not used for PE-to-PE route exchange; rather, it is used between PE and CE routers. To exchange VPNv4 routes between PEs, the vpnv4 address family is required.
- ✗
address-family ipv6 unicast
Why it's wrong here
This address family is used for IPv6 unicast routing and does not support VPNv4 routes. MPLS L3VPN for IPv4 uses VPNv4 address family. While there is a VPNv6 address family for IPv6, this option is for standard IPv6, not VPNv4.
- ✗
address-family ipv4 unicast
Why it's wrong here
This address family is used for standard IPv4 unicast routing and does not carry MPLS labels or VPNv4 prefixes. It cannot be used to exchange VPNv4 routes between PE routers. While it is necessary for underlying routing, it does not fulfill the requirement for MPLS L3VPN route exchange.
- ✓
address-family vpnv4 unicast
Why this is correct
This address family is specifically designed to carry VPNv4 routes with MPLS labels between PE routers. It enables the exchange of customer VPN routes along with their associated route targets and MPLS labels. Configuring this address family under BGP is essential for MPLS L3VPN operation.
Go deeper
Related to this question
Learn chapter
BGP Route Selection and Policy
Key term
MP-BGP for VPN
MP-BGP for VPN is an extension of the Border Gateway Protocol that carries multiple types of network layer information to enable scalable, isolated virtual private networks over a shared provider infrastructure.
Key term
LDP Protocol
LDP, or Label Distribution Protocol, is a protocol that routers use to automatically exchange labels that enable MPLS (Multiprotocol Label Switching) to create fast, efficient paths for data packets across a network.
About these practice questions
Courseiva writes every 300-410 question from scratch — 1,401 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
This 300-410 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 300-410 exam.