Interconnecting Switches for Multi-VLAN Communication

A

The correct answer is A. trunk port.

A trunk port is a type of port that is used to interconnect switches for multi-VLAN communication. Trunk ports are capable of carrying traffic for multiple VLANs simultaneously by adding a VLAN tag to the Ethernet frame.

In a VLAN environment, each VLAN is assigned a unique identifier, called a VLAN ID or a VLAN tag. When a switch receives a frame, it checks the VLAN ID of the frame to determine which VLAN the frame belongs to. If the frame belongs to a VLAN that is configured on the switch, the switch forwards the frame to the appropriate port(s) that are members of that VLAN.

Trunk ports use a trunking protocol, such as IEEE 802.1Q or Cisco's proprietary Inter-Switch Link (ISL), to carry traffic for multiple VLANs over a single physical link. When a frame is sent out of a trunk port, the switch adds a VLAN tag to the frame to indicate which VLAN the frame belongs to. When the frame reaches its destination switch, the switch removes the VLAN tag and forwards the frame to the appropriate port(s) based on the VLAN ID.

Access ports, on the other hand, are used to connect end devices, such as computers, printers, and servers, to the switch. Access ports are configured to belong to a single VLAN and do not add a VLAN tag to the Ethernet frames. Interface ports and switch ports are not specific types of ports in the context of VLAN communication.

Therefore, the correct answer is A. trunk port.