350-501 Services Practice Question
Exhibit
Refer to the exhibit. ! On PE1 interface Loopback0 ip address 10.0.0.1 255.255.255.255 ! interface GigabitEthernet0/0/0 mpls ip ! router ospf 1 router-id 10.0.0.1 network 10.0.0.0 0.255.255.255 area 0 network 192.168.0.0 0.0.255.255 area 0 ! router ldp ! router bgp 65000 neighbor 10.0.0.2 remote-as 65000 neighbor 10.0.0.2 update-source Loopback0 ! address-family vpnv4 neighbor 10.0.0.2 activate neighbor 10.0.0.2 send-community extended !
Refer to the exhibit. Which prerequisite for MPLS L3VPN is missing on PE1?
⚠ Common exam trap
Cisco often tests the misconception that MPLS or LDP configuration alone is sufficient for L3VPN, when in fact the VRF definition is the mandatory first step that candidates overlook.
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
✓
VRF is not defined
The exhibit shows that PE1 has an interface configured with an IP address and MPLS enabled, but no VRF definition is present. For MPLS L3VPN, a VRF must be defined on the PE router to separate customer routing tables and to associate the customer-facing interface with that VRF. Without the VRF, the PE cannot import/export VPN routes or maintain per-VPN routing instances, which is a fundamental prerequisite for L3VPN operation.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
MPLS is not enabled on the interface
Why it's wrong here
`mpls ip` is present.
- ✗
LDP is not enabled globally
Why it's wrong here
LDP is enabled with `router ldp`.
- ✓
VRF is not defined
Why this is correct
No `ip vrf` definition or VRF applied to any interface.
- ✗
OSPF is not redistributed into BGP
Why it's wrong here
Redistribution is done within the VRF, but VRF itself is missing.
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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.