mediumMultiple Choice
300-410 Practice Question: Examine the following configuration on a PE…
Examine the following configuration on a PE router:
ip vrf CUSTOMER-C
rd 200:1 !
interface GigabitEthernet0/3 ip vrf forwarding CUSTOMER-C ip address 10.2.2.1 255.255.255.252
!
router ospf 1 vrf CUSTOMER-C network 10.2.2.0 0.0.0.3 area 0
!
router bgp 65000
address-family ipv4 vrf CUSTOMER-C redistribute ospf 1 exit-address-family
What is missing from this configuration?
⚠ Common exam trap
300-410 often tests the misconception that RD and RT are the same or that RTs are optional. Candidates must remember that RTs are mandatory for VRF route import/export.
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 VRF is missing route-target export and import commands.
In MPLS L3VPN, a VRF requires route-target export and import commands to control the distribution of VPN routes via MP-BGP. Without these, the VRF cannot import or export routes, and the VPN will not function. The configuration shows a VRF with RD but no route-targets, so they are missing.
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 VRF is missing route-target export and import commands.
Why this is correct
Without route-target export and import commands under the VRF, BGP cannot populate the VPNv4 route-target extended community, so no routes are exchanged between VRFs. The stem's configuration lacks these, preventing the OSPF-redistributed routes from being imported into CUSTOMER-C.
- ✗
The OSPF network command should use a wildcard mask of 0.0.0.0.
Why it's wrong here
A wildcard of 0.0.0.0 matches only the single address 10.2.2.1, whereas 0.0.0.3 correctly matches the /30 subnet containing 10.2.2.0-10.2.2.3. It is tempting because host masks appear in loopback or point-to-point statements, but here the subnet mask demands the wider wildcard.
- ✗
The BGP neighbor must be configured under the VRF address-family.
Why it's wrong here
No BGP neighbour is required here: the address-family redistributes OSPF into BGP so the PE advertises the customer's routes. It is tempting because eBGP peerings normally need explicit neighbours, and that would be correct for a PE-CE BGP session, but this scenario relies on redistribution instead.
- ✗
The VRF must have a route distinguisher that matches the route-target.
Why it's wrong here
The route distinguisher and route target serve separate functions: the RD makes VPNv4 prefixes unique, while the RT controls import and export into VRFs. They need not match. Requiring them to match is tempting because both are configured as 200:1-style values, yet the missing element is the route-target export/import under the VRF.
Visual reference
Quick reference
Routing Protocol Comparison
| Protocol | Metric | Max Hops | Algorithm | Type |
|---|---|---|---|---|
| RIP v2 | Hop count | 15 | Bellman-Ford | Distance vector |
| OSPF | Cost (bandwidth) | Unlimited | Dijkstra (SPF) | Link state |
| EIGRP | Composite metric | Unlimited | DUAL | Hybrid |
| IS-IS | Cost | Unlimited | Dijkstra | Link state |
| BGP | Policy / attributes | Unlimited | Path vector | Path vector |
RIP's 15-hop limit makes it unsuitable for large networks. OSPF and EIGRP dominate modern enterprise deployments.
Go deeper
Related to this question
Learn chapter
Introduction to ENARSI Exam and Network Fundamentals
Key term
MPLS Layer 3 VPN
A technology that uses Multiprotocol Label Switching to create secure, scalable virtual private networks that connect multiple sites at the network layer, where the service provider manages routing between customer sites.
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.
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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.