The answer is that the data MDT group is not within the configured data MDT group range on the receiving PEs. In an MVPN data MDT group configuration using Rosen GRE encapsulation (Profile 1), each PE must have a matching data-MDT group range defined under the VRF; if the dynamically assigned group address falls outside this range, the receiving PE will ignore the BGP MDT SAFI route and refuse to join the data MDT, even though the source PE correctly advertises it. This question tests your understanding of how data MDT boundaries are enforced in Cisco SPCOR / CCNP Service Provider Core 350-501, specifically the distinction between default MDT and data MDT behavior—a common trap is assuming that BGP advertisement alone guarantees group membership. Remember the memory tip: “Range rules the join”—if the data MDT group isn’t inside the configured range on the receiver, no join occurs, regardless of the source’s state.
350-501 Architecture Practice Question
This 350-501 practice question tests your understanding of architecture. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A service provider offers IPTV services using multicast. The network uses Multicast VPN (MVPN) with Rosen GRE encapsulation (Profile 1) in an MPLS L3VPN environment. The Provider Edge (PE) routers participate in both the default MDT and data MDT for high-bandwidth streams. Recently, a new channel was added, and it uses a data MDT. The content server is attached to a PE that is acting as a multicast source. Other PEs are receivers. Upon adding the channel, some receivers report missing packets. The network engineer checks the PEs and notices that the data MDT group address is being advertised via BGP as an MDT SAFI route, but some PEs are not joining the data MDT. The source PE's multicast routing table shows that it believes data MDT is active. Which architecture issue is most likely preventing some PEs from joining the data MDT?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
The source PE is not sending IGMP joins for the data MDT group.
Why wrong: Incorrect. The source PE does not send IGMP joins; it originates the multicast stream.
B
The default MDT group is flapping.
Why wrong: Incorrect. Default MDT flapping would affect all channels, not just this specific data MDT.
C
The PIM sparse mode RP is not reachable.
Why wrong: Incorrect. Data MDT often uses SSM, which does not require an RP; if using ASM, RP reachability could affect, but the issue is specific to joining the data MDT group.
D
The data MDT group is not within the configured data MDT group range on the receiving PEs.
Correct. If the group is outside the configured range, the PE will not participate in that data MDT.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The data MDT group is not within the configured data MDT group range on the receiving PEs.
The data MDT group must be within the configured data-MDT group range on each PE; if not, the PE will ignore the BGP MDT SAFI route and not join the data MDT. Source PE IGMP joins are not relevant; default MDT issues are separate; PIM RP reachability might affect default MDT but not data MDT join if using SSM.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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 PE is not sending IGMP joins for the data MDT group.
Why it's wrong here
Incorrect. The source PE does not send IGMP joins; it originates the multicast stream.
✗
The default MDT group is flapping.
Why it's wrong here
Incorrect. Default MDT flapping would affect all channels, not just this specific data MDT.
✗
The PIM sparse mode RP is not reachable.
Why it's wrong here
Incorrect. Data MDT often uses SSM, which does not require an RP; if using ASM, RP reachability could affect, but the issue is specific to joining the data MDT group.
✓
The data MDT group is not within the configured data MDT group range on the receiving PEs.
Why this is correct
Correct. If the group is outside the configured range, the PE will not participate in that data MDT.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Got this wrong? Here's your next step.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 350-501 NAT questions on configuration and troubleshooting.
Architecture — This question tests Architecture — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: The data MDT group is not within the configured data MDT group range on the receiving PEs. — The data MDT group must be within the configured data-MDT group range on each PE; if not, the PE will ignore the BGP MDT SAFI route and not join the data MDT. Source PE IGMP joins are not relevant; default MDT issues are separate; PIM RP reachability might affect default MDT but not data MDT join if using SSM.
What should I do if I get this 350-501 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 350-501 NAT questions on configuration and troubleshooting.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.