H12-821_V1.0 · Question #806
The deployment of port isolation technology in Ethernet can realize layer 2 interoperability and layer 3 isolation, making the network more flexible.
The correct answer is B. FALSE. B is correct because port isolation (also called Private VLAN or port-based isolation) actually achieves the opposite of what the statement claims - it provides layer 2 isolation (preventing direct communication between isolated ports on the same VLAN) while allowing layer 3…
Question
Options
- ATRUE
- BFALSE
How the community answered
(59 responses)- A22% (13)
- B78% (46)
Explanation
B is correct because port isolation (also called Private VLAN or port-based isolation) actually achieves the opposite of what the statement claims - it provides layer 2 isolation (preventing direct communication between isolated ports on the same VLAN) while allowing layer 3 interoperability (routing through a gateway). The statement has the layers inverted.
Why A is wrong: Saying the statement is true would mean accepting that port isolation enables layer 2 communication between isolated ports, which defeats the entire purpose of the technology - isolating hosts at the data link layer to enhance security and reduce broadcast traffic.
Memory tip: Think "isolation happens at the layer you're working on." Port isolation is a layer 2 (switching) feature, so it creates layer 2 barriers - hosts can only communicate upward through a layer 3 router/gateway, not sideways across the switch. The layers in the original statement are simply flipped.
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