Which command is used to configure an interface as a trunk port in Cisco IOS?

The command "switchport mode trunk" is used to configure an interface as a trunk port in Cisco IOS. A trunk port is necessary for carrying traffic from multiple VLANs (Virtual Local Area Networks) across a single network link. When you set an interface to trunk mode, it allows VLAN tagging, which ensures that frames from different VLANs can travel over the same physical connection while remaining logically separated.

In a typical network environment, trunk ports are commonly found between switches or between a switch and a router, as they facilitate inter-VLAN routing and communication. Unlike access ports, which are designed to carry traffic for a single VLAN, trunk ports support multiple VLANs, making them essential for segmenting traffic within larger networks.

Understanding this command and its purpose is crucial for network configuration and management, particularly in environments that require VLAN segmentation and efficient use of network resources.