What must be true for hosts on different VLANs to communicate with each other?

What must be true for hosts on different VLANs to communicate with each other?

• A. They must be connected to the same switch
• B. They must have the same IP address
• C. A router or Layer 3 switch must be present
• D. They must use the same protocol

Answer: (C)

For hosts on different VLANs to communicate with each other, a router or Layer 3 switch must be present to perform inter-VLAN routing. VLANs (Virtual Local Area Networks) logically segment a network, allowing devices within the same VLAN to communicate directly, while isolating traffic from devices in different VLANs. Since VLANs create separate broadcast domains, devices in different VLANs cannot communicate directly without routing. A router or Layer 3 switch functions to route traffic between these separated broadcast domains. By performing this routing, it allows the necessary traffic to flow between hosts that are on different VLANs, enabling communication. This is essential for maintaining network organization, security, and traffic management. The other options do not address the requirement for inter-VLAN communication effectively. Being connected to the same switch does not solve the isolation issue posed by VLANs. Having the same IP address would not facilitate communication across different networks and is generally discouraged as it can lead to address conflicts. Finally, using the same protocol is irrelevant, as VLAN communication strictly relies on routing capabilities, rather than protocol compatibility.

For hosts on different VLANs to communicate with each other, a router or Layer 3 switch must be present to perform inter-VLAN routing. VLANs (Virtual Local Area Networks) logically segment a network, allowing devices within the same VLAN to communicate directly, while isolating traffic from devices in different VLANs. Since VLANs create separate broadcast domains, devices in different VLANs cannot communicate directly without routing.

A router or Layer 3 switch functions to route traffic between these separated broadcast domains. By performing this routing, it allows the necessary traffic to flow between hosts that are on different VLANs, enabling communication. This is essential for maintaining network organization, security, and traffic management.

The other options do not address the requirement for inter-VLAN communication effectively. Being connected to the same switch does not solve the isolation issue posed by VLANs. Having the same IP address would not facilitate communication across different networks and is generally discouraged as it can lead to address conflicts. Finally, using the same protocol is irrelevant, as VLAN communication strictly relies on routing capabilities, rather than protocol compatibility.