The Concept of Layers (AQA GCSE Computer Science): Revision Note

The Concept of Layers

• Networks have lots of parts that must work together at the same time

  • Different types of networks (e.g. LAN, WAN)

  • Different ways networks are managed (operating models)

  • The internet

  • Wired and wireless connections

  • Encryption (keeping data secure)

  • Addressing (IP and MAC addresses)

  • Protocols (rules for how devices communicate)

• Managing the complexity of networks is helped with the use of layers

What is a layer?

• A layer is a sub part of a more complex task

• Dividing network tasks into layers reduces the complexity and makes each layer more manageable

• An example of layers can be seen in the TCP/IP protocol which uses a 4-layer model known as a 'stack'

What are the advantages of layers?

• Layers are self-contained which makes managing, repairing and upgrading easier as each layer can be worked on independent of other layers

• Layers allow for focus on specific parts of a protocol without affecting other layers

• Promotes data exchange (interoperability) between hardware and software

TCP/IP Model

What is the TCP/IP model?

• The TCP/IP model is made up of two protocols (TCP & IP), containing 4 layers, that work together to package, address, transmit and receive data on a wide area network (Internet)

• There are four layers that make up the TCP/IP protocol stack:

  • Application

  • Transport

  • Internet

  • Link

• Different protocols operate on different layers