Discovery · Lesson 08

How does a local network reach another network?

A device can deliver directly inside its subnet, but a remote destination needs a next step. A router connects networks, and the default gateway is the local router a device uses for destinations beyond its own subnet.

The remote destination

A device does not need the whole path at once.

First, a device compares the destination IP (Internet Protocol) address with its own subnet. If the destination is local, it delivers directly. If it is remote, it sends the packet to its default gateway.

The gateway is not the final destination. It is the next local router, which can inspect the packet and make the next forwarding decision.

A gateway is a next step, not a shortcut through the whole Internet.Each router only needs enough information to choose where the packet should go next.

Build the model

Four useful roles

01

Local subnet

The address range where a device can deliver directly.

02

Default gateway

The local router used when the destination is outside the subnet.

03

Router

Connects networks and chooses a next hop for traffic.

04

Remote network

A destination range that cannot be reached directly on the current link.

Mini experiment

Choose the next step

Compare a local destination with a remote one and see whether the device delivers directly or uses its gateway.

DECISIONLocal delivery
NEXT STEPDestination device
REASONThe destination is inside the current subnet, so the frame can stay local.

A local destination does not need the default gateway.

Knowledge check

Test your gateway model

Answer five questions. The answer order changes each time.

0 / 5