350-501 Architecture Practice Question
Exhibit
Refer to the exhibit. interface GigabitEthernet0/0/0/0 description Link to PE2 ipv4 address 10.1.1.1 255.255.255.252 ipv6 address 2001:DB8::1/64 ! router ospf 1 router-id 1.1.1.1 network 10.0.0.0 0.255.255.255 area 0 ! router bgp 65001 bgp router-id 1.1.1.1 bgp log-neighbor-changes neighbor 10.1.1.2 remote-as 65002 address-family ipv4 unicast network 10.1.1.0 mask 255.255.255.252 neighbor 10.1.1.2 activate exit-address-family
Refer to the exhibit. The router is configured as a PE router in an MPLS VPN network. Which option correctly identifies a configuration error that would prevent proper operation?
⚠ Common exam trap
Cisco often tests the distinction between OSPF wildcard masks and subnet masks, where candidates mistakenly think any wildcard mask that includes the interface IP is sufficient, but the mask must match the subnet exactly for OSPF to advertise the correct network.
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 OSPF network statement uses an incorrect wildcard mask
The OSPF network statement uses a wildcard mask of 0.0.0.0, which matches only the exact IP address 10.1.1.1, but the interface has a /30 prefix (255.255.255.252), so the correct wildcard mask should be 0.0.0.3 to include the entire subnet. This misconfiguration prevents OSPF from advertising the correct network, breaking MPLS VPN CE-to-PE routing.
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 neighbor remote-as should be the same AS number for iBGP
Why it's wrong here
The neighbor is in a different AS, so eBGP is correct.
- ✗
The interface lacks the 'mpls ip' command
Why it's wrong here
The exhibit does not show MPLS configuration, but the question asks for an error shown in the exhibit; the absence of 'mpls ip' is not visible.
- ✓
The OSPF network statement uses an incorrect wildcard mask
Why this is correct
The wildcard mask 0.255.255.255 is too broad and does not match the /30 prefix correctly.
- ✗
The BGP network statement does not match the interface prefix
Why it's wrong here
The BGP network command can specify a more specific prefix than the interface; it is not an error.
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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.