To allow each device to access its expected network without additional connections, the administrator needs to configure VLANs (virtual LANs) on the switch. VLANs are logical groups of devices that share the same broadcast domain, regardless of their physical location or connection. VLANs can improve network performance, security, and management by isolating traffic and reducing broadcast storms. To configure VLANs on the switch, the administrator needs to assign each device port to a specific VLAN and set the VLAN tagging mode. VLAN tagging is a method of adding a VLAN identifier to the Ethernet frames to indicate which VLAN they belong to. There are two types of VLAN tagging: untagged and tagged. Untagged VLAN tagging means that the switch removes the VLAN identifier from the frames before sending them to the device port. This is suitable for end devices that do not support VLAN tagging, such as PCs, printers, etc. Tagged VLAN tagging means that the switch keeps the VLAN identifier on the frames when sending them to the device port. This is suitable for devices that support VLAN tagging, such as routers, servers, other switches, etc. To allow each device to access the rest of the network, the administrator needs to configure a trunk port on the switch that connects to the uplink. A trunk port is a port that can carry traffic from multiple VLANs using tagged VLAN tagging. This way, the switch can send and receive frames from different VLANs to and from the rest of the network. Therefore, the administrator should do the following to meet the requirements:
Untag an individual VLAN per device port. This will assign each device port to a specific VLAN and remove the VLAN identifier from the frames before sending them to the device port. This will allow each device to access its expected network without additional connections.
Tag the three VLANs across the uplink. This will configure a trunk port on the switch that connects to the uplink and add the VLAN identifier to the frames before sending them to the uplink. This will allow the switch to carry traffic from multiple VLANs to and from the rest of the network.
Reference:
VLANs and Trunks
VLAN Tagging Explained with DTP Protocol
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