What defines a "native VLAN" on a trunk link?

The concept of a native VLAN on a trunk link is primarily associated with the handling of untagged traffic. Specifically, the native VLAN is the default VLAN assigned to a trunk port, and it is responsible for managing any frames that arrive untagged. In other words, when a switch receives frames on a trunk link that lack a VLAN tag, those frames are associated with the native VLAN.

This mechanism is crucial for maintaining communication in environments where both tagged (VLAN-aware) and untagged (non-VLAN-aware) devices operate. Essentially, by designating a particular VLAN as the native VLAN, network administrators ensure that untagged traffic is appropriately processed and directed, preventing data loss and maintaining network efficiency.

The native VLAN typically defaults to VLAN 1 but can be configured to any VLAN as needed. Choosing the appropriate native VLAN is essential to avoid issues such as VLAN hopping or security vulnerabilities that may arise from misconfigurations in trunking.

Other choices may mention different characteristics of VLANs but do not accurately define the specific role of a native VLAN in the context of untagged traffic on trunk links.