What is necessary to apply different policies to traffic for different VLANs?

To apply different policies to traffic for different VLANs, implementing VLAN tagging is essential. VLAN tagging allows network devices to distinguish between various VLANs as data packets are transmitted across the network. By tagging these packets, it becomes possible to identify which VLAN they belong to, enabling the application of distinct security policies, quality of service rules, or access controls tailored to each VLAN's specific requirements.

This is critical in environments where multiple VLANs serve different purposes, such as separating guest traffic from internal business operations or segregating traffic for different departments. Without VLAN tagging, all traffic would be treated as a single entity, making it impossible to apply differentiated policies effectively.