Protocols are the agreed rules that let devices exchange data correctly. This unit covers the key transport and application protocols (TCP, UDP, HTTP, HTTPS and DHCP), how the four-layer TCP/IP model organises communication, how packet switching moves data across a network, and how the choice of transmission media affects performance. The TCP/IP model detail is AHL content.
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Transport protocols: TCP vs UDP
A protocol is a set of rules defining how data is structured, transmitted and received, covering format, timing, sequencing and error checking.
TCP (Transmission Control Protocol) is connection-oriented and reliable. It uses a handshake, acknowledgements, sequencing and flow control to deliver an ordered, error-checked stream of data.
UDP (User Datagram Protocol) is connectionless and has no handshake, making it faster and lighter but without guaranteed delivery or ordering.
Use TCP where accuracy matters, such as web pages, email and file transfer. Use UDP where speed matters and some loss is acceptable, such as video streaming, online gaming and VoIP.
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1. Which protocol is connectionless and is preferred for real-time applications such as video streaming, online gaming and VoIP, where occasional data loss is tolerable?
2. HTTPS secures web communication. Which protocol provides that encryption?
3. In the TCP/IP model, which layer is responsible for addressing and routing packets across different networks using IP addresses?
4. What is the term for wrapping data with the protocol information (headers) it needs before it is transmitted over the network?
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