Common Network Devices

Network Interface Cards (NIC) allow an electronic device to be connected to a network
Network Interface Cards are connected to the motherboard but in most modern systems are usually integrated
Each network interface card has a unique identifier which is known as a media access control address or MAC address which is created during the manufacturing process
Wireless Network Interface Cards (WNIC) are the same as a NIC but use wireless connectivity to connect devices to networks

A MAC address is a 48 bit hexadecimal code where 12 hexadecimal characters are grouped in pairs

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The general format for a MAC address is that each pair of hexadecimal digits are separated by a “-”
An example of a MAC address:

Microsoft has an OUI of 00-15-5D,
a new laptop straight out of a Microsoft production line could have a MAC address of “00-15-5D-45-1B-3F”

Two completely different products can contain the same Network Interface Identifier but they must use their own Organisational Unique Identifier
- Microsoft can have the MAC Address 00-15-5D-45-1B-3F
- Amazon can have the Mac Address 0C-5B-8F-45-1B-3F

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Hubs are generally much cheaper than switches but:
- When a hub receives a data packet it will broadcast it to every device on the network
This creates two potential issues:

As the information is being broadcast to every device it will make unnecessary traffic especially if there are a large number of devices
As every device will receive the data packet, security may be a concern

Switches are also used to connect several devices together just like a hub; however, rather than sending data packets to all devices on the network, the switch will only send the data to its intended device

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This is done by each switch having a lookup table

Port

Mac address

1 DF-42-B2-11-4D-E3

2 11-14-F2-1D-C3-C6

3 00-4B-17-7C-A2-C9
When a switch receives a data packet, it examines the destination MAC address of the box and looks up that address in its lookup table
Once it has found the matching MAC address it will then forward the data packet to the corresponding port

Explain the difference between a switch and a hub regarding data forwarding capabilities.

[2]

A switch forwards data packets based on the destination MAC address and only sends data to the intended device [1]

A hub broadcasts incoming data packets to all connected devices [1]

Bridges are used to connect two networks or network segments to create a single larger network
An important note is that a bridge cannot communicate with external networks such as the internet like a router can

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Common Network Devices (CIE IGCSE ICT)