1. Mr C Johnston ICT Teacher www.computechedu.co.uk
BTEC IT Unit 28 - Lesson 03 TCP/IP and Application Layer Protocols
Mr C Johnston
ICT Teacher

2. Session Objectives
Understand what the TCP/IP model is and the role of its different layers,
Be able to describe a range of different protocols accessed by the application layer of the TCP/IP model,
Be able to give practical examples of how the different application layer protocols are used by network users.

3. Protocols
Protocols are a set of rules which control something – in English its protocol to start a sentence with a capital letter and end with a punctuation mark,
In networking they standardise the way different devices talk to one another – sometimes known as a handshake.
The internet uses a model called TCP/IP (Transmission Control Protocol / Internet Protocol), which contains a number of different sets of rules to control different types of communication – the rule sets are known as a protocol suite.
The TCP part deals with communicating between applications in your computer – e.g. web browser to OS to NIC driver,
The IP part controls communication between different devices.

4. TCP/IP Model
The TCP/IP (transport control protocol / internet protocol) has 4 different layers,
Source Device
Destination Device
Application
Transport
Internet
Link

5. TCP/IP Model Layers Each layer within the model has a different job,
The link layer is the lowest and deals with how the data will actually be sent through the network hardware – how the data is transmitted along cables / fibre, navigates through routers, servers etc
The internet layer packs data into data packets known as IP datagrams, which contain source and destination address information that is used to forward the datagrams between hosts and across networks. The internet layer is also responsible for routing of IP datagrams.
The transport layer establishes communication between the source and destination hosts and permits them to carry on a conversation

6. Application Layer
The application layer is the highest layer within the TCP/IP and provides protocols which we use, through the use of software applications,
You need to be aware of the function of the following application layer protocols
HTTP,
HTTPS,
SMTP,
POP3,
IMAP,
FTP,
DHCP,
DNS,
RDP,
SNMP,

8. BTEC Book – Unit 29 p6
BTEC Book – Unit 09 p10
BTEC Book – Unit 10 p14-17

9. D1 Overview
D1 Requires you to explain the role of the TCP/IP protocol and how it links to the application layer,
The assignment ask you to add a final section to your report which gives a technical explanation of TCP/IP application layer protocols used on the internet,
You could structure this by having:
A detailed overview of TCP/IP including diagrams showing the layers and a detailed explanation the job of each layer,
A table similar to the one produced during the exercise which explains technically how each of the application layer protocols work – diagrams will help.

10. D1 – Explain the role of the TCP/IP protocol and how it links to application layer protocols
For D1, you should give a technical explanation of application layer protocols in relation to the TCP/IP protocol,
You must remember that when explaining the layer protocols ensure it relates to TCP/IP,
For explain remember you need to give a detailed account to give the meaning of something with reasons. Include the ‘how’ and ‘why’ of the topic of interest.