The network device that can join several LANs and can also divide a network to…

Concept

A bridge is a data-link-layer device that learns source MAC addresses and uses its forwarding table to filter or forward frames between LAN segments. This creates separate collision domains and reduces unnecessary cross-segment traffic, although broadcasts and frames with unknown destinations may still be flooded.

Application

The stem asks for a device that connects LAN segments and segments their traffic. After learning MAC locations, a bridge can keep known unicast frames on the relevant path instead of repeating every bit across all segments; this is the traffic-isolation function meant here.

Contrast

• Gateway translates or mediates between networks or applications that use dissimilar protocols.

• Hub repeats every incoming bit to all other ports and keeps connected devices in one shared collision domain.

• Network Interface Card provides one host with the hardware interface needed to access a network.

• Bridge learns MAC addresses and selectively filters or forwards frames between LAN segments.

Cross-check

A hub does not segment the collision domain, while a bridge both interconnects LAN segments and filters learned traffic between them. Therefore, the required device is a bridge.