Network Protocol Basics and Terminologies

This post gives an overview of network protocols and covers some common network protocol terminologies with examples.

The definition of “protocol” varies quite a bit, but simply put, a protocol is just a set of rules.

In networking, protocols refer to formal standards and policies that define the way two or more devices communicate on a network.

Basics of Network Communication

For a network to exist, we need a minimum of two connected devices.

• Network communication happens at different levels or layers (OSI model and TCP/IP model)
• Each layer of network communication is responsible for passing the information on to the next layer in the stack.
• Data transferred between layers is known as a Protocol Data Unit (PDU).
• These network layers of communication allow for better troubleshooting.
• The rise of the internet and new technology has changed the way devices communicate with each other and thus may require new protocols.

Network Protocol Terminologies

LAN: LAN stands for “Local Area Network” and refers to a network that is not publicly accessible by the internet. Examples of this are home or office network.

WAN: WAN stands for “Wide Area Network” and generally refers to large dispersed networks and, more broadly, the internet.

ISP: ISP stands for “Internet Service Provider” and refers to the company responsible for providing you access to the internet.

NAT: Network Address Translation allows requests from outside your local network to be mapped to devices within your local network.

Firewall: A firewall is a piece of hardware or software that enforces what type of network traffic is and is not allowed. This is generally done by establishing rules for which ports should be externally accessible.

Router: A router is a network device whose main goal is to transfer data back and forth between different networks. This device allows requests to be made to the internet and for information to be sent back to the devices on a local network.

Switch: The basic function of a switch is to provide access between devices on a local network. An example is an Ethernet switch.

Network Interface: This component allows you to connect to a public or private network. It provides the software required to utilize networking hardware. An example of this is the Network Interface Cards (NICs).

Port: A port is a logically defined connection location. Ports provide a destination endpoint for communication and the transfer of data. The ports range from 0 to 65535.

Packet: A packet is the basic unit of data transferred over a network. A packet has a header that gives information about the packet (source, destination, etc) and a body or payload containing the actual data being sent.

In summary

In this post, we covered the basics of network protocols and common terminologies. We discussed what a protocol is and how devices communicate with each other over a network, at a high level.