Today is the fourth day of the Networking Series and today's topic will be about TCP/IP and the OSI Layers Model.
What is TCP/IP?
TCP/IP also called the Internet Protocol Suite are two network protocols working together to form a computer network. TCP/IP is the most widely used Network Protocol and works as the backbone of the internet.
The TCP/IP defines four layer model.
4. Application Layer
3. Transport Layer
2. Internet Layer
1. Link Layer
TCP or Transmission Control Protocol
TCP stands for Transmission Control Protocol. It handles the transferring of data in bytes between devices of the network and the internet that are communicating via the IP network. It is a reliable stream transport port-to-port protocol. TCP first establishes the connection between the sender and receiver and then transfers the data and only closes the connection when all the data is sent or received and the connection is no longer needed.
TCP when sending data divides the data into smaller parts called segments and then numbers each segment with an id. This way on the receiver end it checks all the parts and if some part is missing it will ask for the missing part from the sender. After ensuring all the parts of the requested data are received, it will reorder them as they were at the time of the sending based on their id. World Wide Web aka the Web, email service and filesharing services all rely on the use of TCP as it is a part of the transport layer of IPS.
IP or Internet Protocol
The IP or the Internet Protocol primarly works in addressing and routing of the data on the network and the internet. It is what essentailly enabled the Internet. IP has the task of sending bytes or packets from sender to receiver from thier IP Address. Sender and receivers IP addresses are defined on the headers of the packets of the data. IP reads the header and defines the addressing methods to label the route from source to the destination.
The IP has many versions but the IPv4 or Version 4 of the IP is the most used version on the internet. IPv4 uses 32-bit address space which means there are 4,294,967,296 unique address that can be defined with the IPv4. But some of them, many of them are also reserved and the intenet growing day by day, the world is running out of IPv4 addresses. That is where IPv6 comes in. IPv6 is the successor to the IPv4. IPv6 uses a 128-bit address, theoretically allowing 2^128, or approximately 3.4×10^38 addresses. Many of the IP Addresses on the vesion IPv6 are also reserved and cannot is accessed by the genreal public.
340,282,366,920,938,000,000,000,000,000,000,000,000
This ↑ many unique IP addresses with IPv6
OSI Model
The Open System Interconncetion Model is a conceptual model that provides a standard for differnet computer networks to communicate with each other. It was created by Internation Organization for Standardization. It can be seen as a universal langauge for the computer networks to communicate. The OSI model is not followed much in the industry as IPS is more simpler model to use. But the OSI is still very usefull for the troubleshooting of the networks.
The OSI defines a seven layer model.
7. Application Layer
6. Presentation Layer
5. Session Layer
4. Transport Layer
3. Network Layer
2. Data Link Layer
1. Physical Layer
Both OSI and TCP/IP works simmilarly. But TCP/IP is preffered over OSI for the Internet and OSI is preffered over TCP/IP for troubleshooting the network problems not matter how small or big the problem is. Both are essential to know in the modern Networking World. That's it and that's all.
zainsci