What role does VLAN 1 usually serve in network configurations?

VLAN 1 typically serves as the native VLAN in network configurations. The native VLAN is the default VLAN for Ethernet frames that are untagged; it is the VLAN that will carry traffic from devices that have not been assigned to any specific VLAN. In most switch configurations, VLAN 1 is often set as the native VLAN by default. When a trunk link is configured between switches, any traffic that does not have a VLAN tag will be associated with the native VLAN, allowing for the seamless transmission of untagged traffic.

This configuration is important for network management and ensures that certain protocols, such as Spanning Tree Protocol (STP), can operate across trunked connections without interruption. Although VLAN 1 is often used as the native VLAN, best practices recommend changing its default usage to improve security, since it is widely recognized and can be a target for unauthorized access. This enhances the overall security posture of a network, by reducing the predictability of VLAN configurations.