The OSI Model is a conceptual, implementation-neutral model that describes networking in seven separate layers, where each layer covers a set of functions and tasks.
This model helps us communicate while we do network troubleshooting and architecture.
The TCP/IP Model is an implementation-specific networking model that revolves around the TCP protocol and IP addressing which anchor the Internet as we know it.
Its layers include:
- The Network Layer
- The Internet Layer
- The Transport Layer
- The Application Layer
The OSI layers include: Physical, Data Link, Network, Transport, Session, Presentation, and Application.
- The Physical layer includes physical technologies
- The Data Link layer includes data framing and local MAC addressing
- The Network layer includes connecting to the larger web and IP addressing
- The Transport layer includes protocols that make sure reliable delivery happens
- The Session layer authenticates and maintains communication over a period of time
- The Presentation layer en/decrypts and translates data into presentable form
- The Application layer includes all the applications we interact with that render data
Three broad categories of networks include:
- Local Area Network (LAN), a smaller-sized network that connects multiple devices in a small area
- Campus Area Network (CAN), a larger network that connects multiple computers and devices over a slightly larger area
- Wide Area Network (WAN), the largest-sized network that connects multiple computers, over a geographically large area
The Internet is technically a WAN.
A network is two or more computers or devices that are linked in order to share information.
Networking refers to a large set of standards and protocols that organize and regulate the sharing of information.
A network protocol is a set of standards for Internet traffic.
Among them are the big transport protocols:
- TCP and UDP
- HTTP for web requests
- DNS to convert domain names to IP addresses
- IMAP/POP3 for email
- SMB for access to specific resources