VLANs: Understanding Layer-2 Virtual LANs

Layer-2 VLANs

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Which statement about layer-2 VLAN is true?



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A. B. C. D.


Layer 2 VLANs are a method of logically dividing a single physical switch into multiple virtual switches. Each VLAN is considered a separate broadcast domain, and devices in one VLAN cannot communicate with devices in another VLAN without routing. Here is a detailed explanation of the given statements:

A. VLAN cannot be routed. This statement is incorrect. VLANs can be routed with the help of a router or layer 3 switch. VLANs operate at layer 2 of the OSI model, and routing occurs at layer 3. Layer 3 switches are capable of routing traffic between VLANs, and routers can also be used for inter-VLAN routing.

B. VLANs 1006 through 4094 are not propagated by VTP version 3. This statement is true. VTP (VLAN Trunking Protocol) is a Cisco proprietary protocol used to propagate VLAN information across a network. VTP version 3 introduced support for extended VLANs (VLAN IDs 1006 to 4094), but these VLANs are not propagated by default. You need to enable extended VLAN propagation explicitly.

C. VLAN1 is a Cisco default VLAN that can be deleted. This statement is incorrect. VLAN1 is a default VLAN that exists on all Cisco switches, and it cannot be deleted. VLAN1 is used for management traffic, and best practice is to avoid using it for user traffic.

D. The extended-range VLANs cannot be configured in global configuration mode. This statement is incorrect. You can configure extended-range VLANs (VLAN IDs 1006 to 4094) in global configuration mode on Cisco switches that support them. However, these VLANs are not propagated by default using VTP version 3, as mentioned in answer B.

Therefore, the correct answer to the question is B: VLANs 1006 through 4094 are not propagated by VTP version 3.