Components of a NetworkYear 9 – Networking systems

What is a hub?

A hub is a central connecting device in a network.

Each node is connected directly to the hub.

They receive a data packet from one node and send that data packet to all nodes on the network.

This created a lot of unnecessary network traffic, as most of the nodes will ignore the data because it is not addressed to them.

A better type of hub is called a switch.

What is a switch?

A switch is an intelligent hub that only sends data to a specific node

The switch looks at the address of the data packet and sends it to that address.

A switch reduces the volume of traffic on a network compared to a hub.

What is a router?

A router is a very intelligent hub that directs (routes) data packets to and from other networks.

A router maintains a table of the available routes and their conditions.

It uses this table to determine the best route for a given data packet.

Routers are often used to connect to the Internet.

What is a bridge?

A bridge is a device to link two similar networks.

It often connects networks that use the same protocol such as Ethernet.

A bridge examines each data packet on a network and forwards any data packets addressed to a connected network.

What is a gateway?

A gateway is a link between two different types of networks.

It converts different protocols and transfers data between the two networks.

For example, a gateway could be used to convert a TCP/IP packet to an IPX packet.

A gateway acts as the door between the networks.

All the data must pass through the gateway to reach the other network.

Gateways are not necessarily separate devices but rather are often pieces of software running on servers or in routers.

What is a repeater?

A repeater is used to rebuild a fading signal to its original strength and shape before transmitting it onwards.

For example, the data sent along a UTP cable becomes unreadable after about 100 metres.

A repeater would be installed every 100 metres to rebuild the signal.

What is a Network Interface Card (NIC)?

A network interface card (NIC, pronounced ‘nick’) is an expansion card that allows a device to be connected to a network

NICs are installed into servers, workstations and some other devices.

Each device must have a driver to communicate on the network.

A NIC is usually given a unique address so that it can be identified on the network.

Most NICs require a network cable connection and have connectors on the card for different types of cables.