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I've been a network engineer for almost 4 years now. I thought I understand what a network protocol means. but now I'm having doubts.

For me, Ethernet is a protocol used at layer 2. there would be format for data with fields like src MAC , dest MAC ,... IP is a protocol , src IP , dest IP HTTP , FTP , ... When I use Wireshark, I can see it , I can see the fields.

According to comptia "A network protocol is an established set of rules that determine how data is transmitted between different devices in the same network." Reference "https://www.comptia.org/content/guides/what-is-a-network-protocol"

Then I started dealing with another type of protocols. Like 802.1x For me it looked like a framework more than a protocol. Am I missing something here? are there different types of protocols ?

  • A network protocol is a set of rules for communication. Ethernet is not just a layer-2 protocol, but a complete set of standards for layer-1 and layer-2, from the original IEEE 802.3 to the latest current IEEE 802.3cq, with others waiting for approval, all the way to IEEE 802.3db. You have multiple layer-1 protocols for ethernet. IEEE 802.1X is a protocol for encapsulation and sending EAP (another protocol) over a LAN. – Ron Maupin Jul 10 at 21:01
  • According to my understanding EAP is encapsulated in RADIUS or TACACS. 802.1x is just used to describe the whole process, but not actually present. the only indication of 802.1x in a packet is the Ethertype field in ethernet frame = 0x888E – Shehab White Jul 10 at 21:15
  • IEEE 802.1X is a whole set of rules. I think you are confusing things like requiring a header on a packet to be a protocol. Many protocols use headers, but that is not a requirement for rules. – Ron Maupin Jul 10 at 21:19
  • Yes!! That's exactly were I am confused. Do you mean a protocol does not necessary require a header ? Isn't a protocol "rules for communication". How are communicating devices supposed to interact according to a protocol if we do not send the information in the packet (Header)? I'd be extremely grateful if you clarified this point to me in detail. – Shehab White Jul 10 at 21:27
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    A protocol is a set of rules for communication. Headers may aid in that, but they are not requirements for a set of rules. – Ron Maupin Jul 10 at 21:30
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For me, Ethernet is a protocol used at layer 2.

... and a large family of protocols for layer 1, yes.

Then I started dealing with another type of protocols. Like 802.1x For me it looked like a framework more than a protocol.

No. While there are frameworks to simplify handling of 802.1X, it's a protocol.

A protocol is a "language" convention shared between multiple parties to enable communication. Each receiver needs to understand what the sender exactly means.

A protocol can stand in its own right, or in can rely on other, "lower-level" protocols, e.g. 802.1X uses EAP to talk to a RADIUS or TACACS server, or there is a whole zoo of protocols building on HTTP.

A framework is like a software library that provides higher-level functions built on top of more low-level functions. It's like an API but not part of the operating system level but of the application level. A framework can come as part of an operating system, but most often it's a software library coming with an application.

In any case, a framework is used inside a node, irrelevant to the outside, while a protocol is used between nodes.

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  • Thanks for clarification. – Shehab White Jul 11 at 11:11

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