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--- Data transmission ---


Define the terms: protocol, data packet.


Teaching Note:


Sample Question:


JSR Notes:

JSR point: network pictures or videos reminder.

- A general definition of protocol (to help you understand the meaning of the word):

A set of rules/guidelines that help with interaction between individuals or devices. For example: if you visit the Queen of England, bowing is part of the protocol. The various protocols here in Thailand surrounding how you interact with elders and religious people is another interesting example.

Before getting to the actual networking context, another appropriate analogy when learning about networks would be the set of rules, or the protocol, for addressing and sending a physical letter.:

The protocol is to put the destination address in the middle front of the envelope, and to put the sender's address in the upper left hand corner of the envelope. And there are a set of rules which determine the way the addresses are formatted, for example, the number of digits in the postal code. The stamps - whose total value determination follows more rules - go in the upper right hand corner.

- Networking definition of a protocol:

A network protocol is an agreed upon collection of rules that servers, computers and other devices which transfer data back and forth, must follow in order for the transmissions to be successful. Rules include things like how the data is to be formatted and packaged, and whether or not data compression is allowed.


Standards vs protocols

The two terms overlap a bit, and it can be confusing to distinguish between the two. So, here are the distinctions:

Standards are measurable minimum guidelines for doing something or, more often, making something. And protocols are sets of rules for doing things, particularly specific interactions/communications. So standards are usually more about things, and can be measured/represented with numbers/measurements, whereas protocols are about process; rules about how to do something.



- Data packet

A data packet is a single discrete group of bits, a certain length, that travels along a given network path. It is composed of a header and a payload. The header includes important information required by the protocol for the transfer of the data, such as the origin address and the destination address, and the order in which the data packet is to go when the complete file is reassembled. The payload is the raw data itself.




You'll note that in the one most commonly used networking protocol for the Internet, TCP/IP, the rules for data packets are defined in the "IP" ("Internet Protocol") part of it.

And also note that we will do much more to describe packets in 3.1.11, which is about packet switching networks.