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Protocol Functions

Networking protocols are the standardized rules that govern how devices communicate and exchange data. This topic covers what protocols are, who creates them, their common functions, and how they work together to meet communication needs.

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About this video

Networking protocols are formalized rules that govern how devices transmit and receive data, ensuring that both ends of a communication channel operate with a shared understanding. The concept of a protocol predates computing — it originally described the rules governing communication between governments — but has since been adopted to define standards for data exchange between machines. Just as different styles of written communication follow different conventions, different types of network communication require their own specific rules and structures. A protocol establishes those rules to solve a particular problem or accomplish a specific task in the communication process. Protocols are created by a range of entities, including international standards organizations, technology companies, and individual developers. Vendors such as Cisco produce proprietary protocols that offer specialized advantages but require compatible equipment. While it is technically possible to create a custom protocol, established protocols are widely used because they are proven, interoperable, and well-supported across the industry. Common protocol functions include error detection, flow control, data sequencing, addressing, connection management, and confidentiality — and a single protocol may handle several of these functions simultaneously. Because no single protocol addresses every communication requirement, multiple protocols are typically layered and combined to deliver data in exactly the way needed. This modular approach allows engineers to swap out individual protocols when a different level of security, reliability, or performance is required. The TCP/IP protocol suite has become the dominant standard in modern networking, underpinning everyday traffic such as web browsing and Ethernet communication, and serves as the primary focus for most networking and cybersecurity study.

What you'll learn

What's covered

Networking Protocols

Aligned to

CompTIA Network+
1.4 Explain common networking ports, protocols, services, and traffic types.
1.1 Explain concepts related to the Open Systems Interconnection (OSI) reference model.
CompTIA A+ Core 1
2.1 Compare and contrast Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) ports, protocols, and their purposes.
Cisco CCST Networking
1.5 Describe common network applications and protocols.
1.1 Identify the fundamental conceptual building blocks of networks.
Cisco CCNA
1.5 Compare TCP to UDP
Cisco CCST Cybersecurity
2.1 Describe TCP/IP protocol vulnerabilities.
Cisco CyberOps Associate
4.8 Interpret the fields in protocol headers as related to intrusion analysis.

Key terms

Protocol
A set of rules governing the format and transmission of data between devices.
TCP/IP
The suite of communication protocols used to interconnect network devices on the internet.
Encapsulation
The process of wrapping data with protocol headers as it passes down the layers of the OSI model.
Protocol Stack
A layered set of protocols that work together to handle different aspects of data transmission, with each layer serving a specific function.
Error Detection
A protocol function that identifies corrupted or lost data during transmission to ensure accuracy.
Flow Control
A protocol function that manages the rate of data transmission between devices to prevent overwhelming the receiver.

Transcript

What a Protocol Is

There are a lot of protocols out there. Why so many? What are they trying to accomplish?

Have you ever noticed that when you're talking to somebody really young, they'll just blurt out whatever they're thinking? And then as we get older, we start developing these ideas that we have to interact with other people in certain ways. There are certain unspoken protocols that we learn as we get older.

Same thing with letters. When we're writing a letter, if we were writing a letter to a business, maybe it's for some sort of job that we want, it would be very official. Try to turn that same format into a love letter and it's probably not going to fly well. And vice versa: take something that was written like a love letter and turn it into a business letter, and that probably won't fly well. So there are certain rules when we are writing stuff out, or when we're communicating verbally — certain rules that we follow. That's what a protocol is.

When we're talking about networking protocols, we're talking about these rules that we follow. For instance, when we're talking about telegrams that are being sent back and forth between devices, how are we going to signal that other side saying, "Hey, we have a message to send you, prepare yourself for this message"? And then how are we going to convey with dots and dashes to the other side? Well, we're probably going to use something like Morse code. Morse code needs to be defined, what that is, and we need to be on the same page on both sides. We need to have that same understanding. There's a standard that's being set here. That's what a protocol is.

Originally, protocol was used to describe how governments would talk and communicate with each other. However, we have adapted that now to exchange amongst computing devices. And so, how do we transmit data between devices? The set of rules that govern that.

Who Creates Protocols

There are a lot of different agencies out there that create protocols, these sets of rules. In fact, you could create your own protocol. It probably wouldn't be an efficient use of your time, because there's already great protocols that are out there, but you could create your own set of protocols. And actually, a lot of companies do. For instance, Cisco will create what's called proprietary protocols, that you can only use those certain protocols if you're using their equipment. And there are some advantages to using those protocols that they create.

Common Protocol Functions

Now, when we're communicating between devices, there are certain things that we're trying to accomplish. And so that's what a protocol does: it sets up rules to accomplish some sort of task or solve some sort of problem that we're having. And so there's some common protocol functions that we're trying to achieve — some sort of problem, common problem, that we have.

Now, one thing to understand is that a protocol could do several different things for us. So maybe one protocol does error detection, flow control, and prioritization for us, while another does data sequencing and establishes end communication. And so maybe we want to use both of these protocols in order to help facilitate our needs and what we're trying to accomplish.

How Protocols Work Together

I'm going to use these Legos as an example of how protocols work. Let's say here I have some data that needs to be delivered, and I need to deliver that data with confidentiality. This represents a protocol that will allow me to have some confidentiality of this data. So I'm going to attach this, or utilize this protocol, to deliver this data. Now this data will be delivered with some confidentiality.

Perhaps I also want to make sure that it's accurate, so I need some sort of error detection that will accompany this. So I would choose a protocol that gives me error detection to allow that. Maybe it needs to be connection-oriented. And of course I probably want to do some addressing and make sure that it gets to the right location. So now I've used multiple protocols in order to deliver my data.

The thing is with these protocols, there's more protocols that are out there. I'm not just stuck with these protocols that I chose. In fact, what I could do is, if I'm not happy with this level of confidentiality that this protocol gives me, I could choose a different protocol. Maybe it's one I've developed, or maybe it's one that's already developed, but I can choose a different protocol that will give me this level of security that I'm looking for for this data.

Now, there are a lot of different protocols that we can actually choose from. However, what I will say is that a few of these protocols have really bubbled up to the top as being the primary protocols that we use to establish certain aspects of here.

Getting back to our network communication protocol map, these are all the different protocols that are out there, and we see that it's sorted by color, because often these are the protocols that work well together. And in fact, most of this course we're really going to be covering more this TCP/IP protocol stack right here. So we're going to be talking about stuff in this column right here mostly. This is where things like our web traffic come into play, and things like Ethernet. And so these are the most common protocols that we work with in today's age.

In Review

We started out by defining what a protocol is. Then we got into who creates these protocols. We got into common protocol functions, and then we wrapped things up talking about how protocols work together to deliver whatever it is that we want to deliver, in the way we want it delivered.

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