hardMultiple ChoiceObjective-mapped
300-410 Practice Question: Configures RSPAN on a switch to monitor traffic…
A network engineer configures RSPAN on a switch to monitor traffic from VLAN 10 to a remote switch via VLAN 100 as the RSPAN VLAN. The source switch has: monitor session 1 source vlan 10 rx monitor session 1 destination remote vlan 100. The remote switch has: monitor session 2 source remote vlan 100 monitor session 2 destination interface Gi0/1. The remote switch's Gi0/1 is connected to a network analyzer. The analyzer sees no traffic. The RSPAN VLAN 100 is configured on all intermediate switches with the 'remote-span' command. However, the intermediate switches run MST and VLAN 100 is mapped to a different MST instance than the native VLAN. 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
✓
MST maps VLAN 100 to a different instance, causing the port to be in a blocking state for that instance, thus dropping RSPAN traffic.
RSPAN relies on flooding the mirrored traffic across the RSPAN VLAN. In MST, if the RSPAN VLAN is mapped to a different MST instance than the native VLAN, the spanning-tree topology may block the RSPAN VLAN on some ports. Specifically, if the RSPAN VLAN is in a different MST instance, the port may be in a blocking state for that instance, preventing the mirrored traffic from reaching the destination. The 'remote-span' command does not override MST behavior. The fix is to map the RSPAN VLAN to the same MST instance as the native VLAN or use a single spanning-tree region.
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 RSPAN VLAN is not allowed on the trunk ports between switches.
Why it's wrong here
The scenario states VLAN 100 is configured on all intermediate switches, but MST instance mapping can still cause blocking.
- ✓
MST maps VLAN 100 to a different instance, causing the port to be in a blocking state for that instance, thus dropping RSPAN traffic.
Why this is correct
MST can block VLANs in different instances, preventing RSPAN traffic from traversing.
- ✗
The 'remote-span' command is missing on the source and destination switches.
Why it's wrong here
The 'remote-span' command is only needed on intermediate switches, which have it.
- ✗
The RSPAN VLAN must be the native VLAN on all trunks.
Why it's wrong here
RSPAN does not require the VLAN to be native; it can be any VLAN.
Visual reference
Go deeper
Related to this question
About these practice questions
Courseiva writes every 300-410 question from scratch — 1,966 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or 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.