mediumMultiple Choice
CCNP Practice Question: The purpose of the 'encapsulation replicate'…
What is the purpose of the 'encapsulation replicate' keyword in a SPAN destination configuration?
⚠ Common exam trap
Candidates often confuse 'encapsulation replicate' with duplicating traffic to multiple ports (Option B) or enabling RSPAN (Option C), when in fact it is a simple VLAN tag preservation mechanism that is easily overlooked in favor of more complex concepts.
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
✓
It preserves the original VLAN tag of mirrored frames.
The 'encapsulation replicate' keyword in a SPAN destination configuration ensures that the mirrored frames retain their original 802.1Q VLAN tag when they are sent out the SPAN destination port. Without this keyword, the switch strips the VLAN tag from the mirrored frames, which can cause issues if the monitoring device relies on VLAN information for analysis. This keyword is specifically used to preserve the original VLAN ID for accurate traffic inspection.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
It preserves the original VLAN tag of mirrored frames.
Why this is correct
The 'encapsulation replicate' keyword tells the SPAN destination port to preserve the original 802.1Q VLAN tag on every mirrored frame sent to the monitoring device. Without this keyword, the switch strips the VLAN tag and delivers untagged frames, which can obscure which VLAN a packet originally traversed. Using this feature ensures the monitor can see VLAN membership, which is critical for troubleshooting per-VLAN issues.
- ✗
It duplicates the mirrored traffic to multiple destination ports.
Why it's wrong here
SPAN sessions do not use 'encapsulation replicate' to duplicate traffic to multiple destinations; that keyword only governs whether the 802.1Q header is retained. Local SPAN supports a single destination port per session (or a single destination VLAN for RSPAN), and sending copies to multiple monitors requires separate sessions or additional configuration. Replicating to multiple ports is a distinct function, not related to tag preservation.
- ✗
It enables RSPAN functionality.
Why it's wrong here
RSPAN (Remote SPAN) is enabled by configuring a dedicated RSPAN VLAN as the destination, not by using 'encapsulation replicate'. With RSPAN, mirrored traffic is sent onto a specified VLAN that carries it across switches to a remote monitoring port. The 'encapsulation replicate' keyword is only applicable to local SPAN destination ports and does not change the fundamental SPAN architecture.
- ✗
It allows the destination port to send traffic as well.
Why it's wrong here
SPAN destination ports are set to a special monitor mode that stops them from participating in normal Layer 2 forwarding, so they cannot send regular data traffic. The only traffic that egresses a SPAN destination port is the mirrored frames being sent to the attached analyzer; typical production traffic is not forwarded. Thus, 'encapsulation replicate' has no effect on the port's ability to transmit normal traffic—that capability is disabled by the SPAN configuration itself.
Visual reference
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-401 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 350-401 exam.