Which of the following is a network interconnectivity device that translates different communication
protocols and is used to connect dissimilar network technologies?

A.
Gateway

B.
Router

C.
Bridge

D.
Switch

Explanation:

A gateway is a network interconnectivity device that translates different communication protocols
and is used to connect dissimilar network technologies. It provides greater functionality than a
router or bridge because a gateway functions both as a translator and a router. Gateways are
slower than bridges and routers. A gateway is an application layer device.
Answer option B is incorrect. A router is an electronic device that interconnects two or more
computer networks. It selectively interchanges packets of data between them. It is a networking
device whose software and hardware are customized to the tasks of routing and forwarding
information. It helps in forwarding data packets between networks.
Answer option C is incorrect. A bridge is an interconnectivity device that connects two local area
networks (LANs) or two segments of the same LAN using the same communication protocols, and
provides address filtering between them. Users can use this device to divide busy networks into
segments and reduce network traffic. A bridge broadcasts data packets to all the possible
destinations within a specific segment. Bridges operate at the data-link layer of the OSI model.
Answer option D is incorrect. A switch is a network device that selects a path or circuit for sending
a data unit to its next destination. It is not required in smaller networks, but is required in large
inter-networks, where there can be many possible ways of transmitting a message from a sender
to destination. The function of switch is to select the best possible path.
On an Ethernet local area network (LAN), a switch determines from the physical device (Media
Access Control or MAC) address in each incoming message frame which output port to forward it
to and out of. In a wide area packet-switched network, such as the Internet, a switch determines
from the IP address in each packet which output port to use for the next part of its trip to the
intended destination.