Q18
1 markMCQSection A

Which network device serves as the entry and exit point of a network, as all data coming in or going out of a network must first pass through it in order to use routing paths ?

Computer Networks
Network Devices — Gateway

Options

(A)Modem
(B)Gateway
(C)Switch
(D)Repeater
Official Answer

Correct option: (B) Gateway


A gateway is the network device that acts as the entry/exit point of a network — all traffic entering or leaving the network passes through it so it can be routed towards its destination, often across dissimilar networks.

gatewaynetwork deviceentry and exit pointroutingdissimilar networksmodemswitchrepeater

Marking Scheme

  • 11 mark for selecting option (B) Gateway; no partial marks in MCQ.

Hint

Think of the device positioned at the 'boundary' of a network that connects it to the outside world, unlike devices that only work within one LAN.

Quick Oral Answer

A gateway is the network device that acts as the entry and exit point of a network, routing all incoming and outgoing traffic, even between dissimilar networks.

Analysis & Explanation

This is a definition-based question that tests whether students can distinguish between commonly confused networking devices.


Why (B) is correct

  • A gateway sits at the boundary of a network and connects it to other networks (including dissimilar networks with different protocols).
  • All inbound and outbound traffic is funnelled through the gateway before it can be routed to its final destination.

Why the distractors are wrong

  • (A) Modem — converts digital signals to analog (and back) for transmission over telephone/cable lines; it does not manage routing of traffic between networks.
  • (C) Switch — connects devices within the same LAN using MAC addresses; it works inside one network, not as its entry/exit boundary.
  • (D) Repeater — simply regenerates and amplifies a weakening signal to extend cable length; it has no role in routing or network boundaries.

Common Mistakes

  1. 1Confusing Gateway with Modem, since both are boundary-facing devices for internet connectivity.
  2. 2Selecting Switch, forgetting that a switch only operates within a single LAN and does not connect a network to the outside.

Interesting Facts

A gateway can connect networks running entirely different protocol stacks — e.g., linking a traditional PSTN telephone network to a VoIP network.

Home Wi-Fi routers usually combine the functions of a router, switch, and gateway into a single device, which is why the term 'gateway' is often loosely used for a home router.

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Frequently Asked Questions

How is a Gateway different from a Router?

A router forwards data between networks using the same protocol, while a gateway can connect networks using different protocols, translating data as needed.

Is a Gateway the same as a Modem?

No. A modem modulates/demodulates signals for transmission over telephone or cable lines, while a gateway manages entry/exit routing between networks, often of different types.