hardMultiple ChoiceObjective-mapped
300-410 Practice Question: A company uses IP SLA to track a route to a…
A company uses IP SLA to track a route to a remote network via a DMVPN tunnel. Router R1 (hub) has:
ip sla 5
icmp-echo 172.16.0.1 source-ip 10.0.0.1 frequency 10
ip sla schedule 5 life forever start-time now track 5 ip sla 5 reachability ip route 192.168.1.0 255.255.255.0 Tunnel0 track 5
Tunnel0 is a DMVPN tunnel to spoke R2. The tunnel is up, but the route is intermittently removed. Show output on R1:
show ip route 192.168.1.0 % Subnet not in table
show track 5
Track 5 IP SLA 5 reachability
Reachability is Down 2 changes, last change 00:00:05
What is the root cause?
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 source IP of the IP SLA probe is not the tunnel source, so the probe is sent out the physical interface and does not reach the destination.
The IP SLA probe is sent to 172.16.0.1, which is the tunnel IP of R2. However, the DMVPN tunnel might be using a different encapsulation (e.g., mGRE) and the probe might be sent over the physical interface instead of the tunnel, or the tunnel might be in a VRF. The correct answer is that the IP SLA probe is sourced from 10.0.0.1, which is not the tunnel source, so the probe goes out the physical interface and may not reach 172.16.0.1, causing the track to go down.
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 source IP of the IP SLA probe is not the tunnel source, so the probe is sent out the physical interface and does not reach the destination.
Why this is correct
The probe should be sourced from the tunnel source IP to ensure it goes through the tunnel; otherwise, it may be dropped or not reach the target.
- ✗
The DMVPN tunnel is down because the spoke is not reachable.
Why it's wrong here
The tunnel is up per the scenario, but the probe fails due to source IP mismatch.
- ✗
The IP SLA frequency is too low, causing the track to go down after 10 seconds of no response.
Why it's wrong here
Frequency is not the issue; the probe is not reaching the target at all.
- ✗
The route is removed because the track is down, but the track is down due to a routing loop in the DMVPN network.
Why it's wrong here
There is no evidence of a routing loop; the issue is with the probe source.
Visual reference
Go deeper
Related to this question
Learn chapter
Introduction to ENARSI Exam and Network Fundamentals
Key term
IP SLA for Path Control
IP SLA for Path Control is a Cisco technology that uses active network measurements to dynamically influence routing decisions and redirect traffic along a preferred path when network conditions change.
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.
About these practice questions
This 300-410 question is part of Courseiva's 1,966-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.