The Internet Protocol
Jay Kadlag
Introduction
Everyday, billions of devices—like computers, smartphones, and smart TVs—talk to each other over the internet. But how do they know where to send and receive data? The answer is Internet Protocol (IP).
Think of the internet like a huge postal system. Just as houses have unique addresses, every device connected to the internet has a unique IP address. When you send data (like a message or a video), it’s like mailing a letter. The internet uses IP to figure out where the letter needs to go and how to deliver it.
In this article, we’ll explore how the internet works, how IP addresses help devices communicate, and why this system is so important.
Understanding Networks and the Internet
What is a Network?
A network is a group of computers that are connected and can share information with each other. It’s similar to a group of friends who stay in touch, share news, and work together on different activities.
Computers within a network can communicate with each other, and since networks are also connected to one another, a computer in one part of the world can send information to another computer far away.
Now that we know what a network is, let’s see how all these networks come together to form the internet.
What is the Internet?
The Internet is a huge network made up of millions of smaller networks that are all connected. It connects computers, smartphones, tablets, and other devices all over the world.
In fact, the word “Internet” comes from the idea of interconnected networks.
Computers connect to each other and to the Internet using wires, cables, radio waves, and other types of network technology. When data is sent over the Internet, it is converted into tiny signals of light or electricity, called bits. The receiving computer then reads and understands these bits.
The speed of the Internet depends on how many bits can pass through the wires, cables, or radio waves at the same time. The more bits that can travel at once, the faster the Internet works.
To make communication possible, the internet relies on a set of rules known as protocols.
Protocols
In networking, a protocol is a set of rules that computers follow to communicate with each other. These rules make sure that information is sent and received correctly.
Even if two devices are different—like a Windows laptop and an iPhone—they can still communicate because they follow the same protocols.
Examples of Protocols:
IP (Internet Protocol) – Helps send data to the right place on a network.
TCP (Transmission Control Protocol) – Makes sure data is delivered fully and in the correct order.
UDP (User Datagram Protocol) – Sends data fast but doesn’t check if it was received.
DNS (Domain Name System) – Changes website names into IP addresses so computers can find them.
One of the most important protocols that keeps everything running smoothly is the Internet Protocol (IP).
Understanding IP (Internet Protocol)
What is an IP?
The Internet Protocol (IP) is the system that allows computers and devices to send and receive data across networks.
When you send something over the internet—like an email or a website request—your data is broken into small pieces called packets. Each packet carries instructions (IP information) on where to go and how to get there.
Why do we need an IP?
Every device connected to the internet needs a unique IP address so that data knows where to go. Without IP addresses, sending information over the internet would be like mailing a letter without an address—it wouldn’t reach the right place!
When data is sent over the internet, the sender and receiver might be in different places, using networks with different speeds. To handle this, protocols manage the flow of data and decide which device can use the connection at a given time.
Since IP is the backbone of communication, let’s see how it works through IP addresses.
IP Addresses
An IP address is a unique number assigned to every device or website connected to the Internet. It looks like a series of numbers, such as 192.168.1.1.
It is a Layer 3 property, meaning it helps devices communicate on a network.
Types of IP Addresses:
Dynamic IP Address – Assigned automatically by something called DHCP (Dynamic Host Configuration Protocol). These addresses can change over time.
Static IP Address – Manually assigned and does not change.
Every IP address has two parts:
Network Portion - Identifies the network the device belongs to.
Host Portion – Identifies the specific device within that network.
Since these numbers are hard to remember, the DNS (Domain Name System) converts website names into IP addresses, as explained in one of my previous article on DNS.
To better manage networks, IP addresses are structured with subnet masks.
Subnet Mask and Its Importance
What is a Subnet?
A subnet is a way to divide a big network into smaller, more manageable parts.
What is a Subnet Mask?
A subnet mask determines which part of an IP address belongs to the network and which part belongs to the host.
For example: 192.168.1.1/24
/24 means the first 24 bits represent the network portion.
The remaining 8 bits are used for the host portion, allowing multiple devices within that network.
Why is this Important?
The subnet mask helps devices determine whether another IP address belongs to the same network or if it needs to communicate through a router.
If the destination IP is in the same subnet, data is sent directly using MAC addresses. If it is outside the subnet, the packet is sent to the default gateway.
Default Gateway
What is It?
The default gateway is the router that connects a subnet to other networks. Each network has a router (gateway) that knows how to forward packets to the correct destination.
A router has multiple interfaces, each belonging to a different subnet.
How It Works?
If a computer wants to communicate with another device in the same subnet, it sends the data directly.
If a computer needs to communicate with a device outside its subnet, the data is sent to the default gateway, which then forwards it to the correct destination.
IP Packets
What is It?
When we think about an IP packet, we usually see it as data with a source and destination IP address. However, there’s much more to it!
An IP packet has two main parts:
Header – Contains important details for routing and network control.
Data – The actual information being sent.
Although we mostly focus on the data being sent, the header is just as important because it helps with routing, troubleshooting, and error handling.
The header size can range from 20 to 60 bytes, depending on whether optional fields are included. While this adds extra data, it ensures that packets are delivered smoothly and efficiently.
The data section can hold up to 65,536 bytes, but in most cases, it is limited to around 1500 bytes due to network restrictions like the Maximum Transmission Unit (MTU).
If a packet is too large, it may be broken into smaller pieces (fragments), but this is usually avoided because it can make data transfer more complicated.
Version – Shows whether the packet is using IPv4 or IPv6.
Header Length – Indicates the size of the header.
Type of Service – Helps decide how important the packet is compared to others. Some packets need to be sent quickly, like video calls, while others can wait.
Total Length – The complete size of the packet, including both the header and data.
Identification – A unique number given to a packet. If the packet is split into smaller parts, this number helps put them back together.
Flags – Controls whether a packet can be broken into smaller parts or must stay whole.
Fragment Offset – If a packet is split into smaller parts, this number helps place each part in the right order.
Time to Live (TTL) – Limits how many times a packet can be passed between networks before it is removed. This prevents packets from traveling forever if something goes wrong.
Protocol – Identifies what type of data is inside the packet. It could be TCP (for web pages and file transfers), UDP (for video calls and gaming), or ICMP (for network testing).
Header Checksum – A number used to check if the header was damaged while traveling.
Source and Destination IP Addresses – Show where the packet came from and where it needs to go.
Explicit Congestion Notification (ECN) – Helps reduce congestion in the network by signaling the sender to slow down instead of losing data.
Why Does This Matter?
Understanding these details helps in troubleshooting network issues, optimizing data transfer, and making sure that packets reach their destination efficiently and securely.
The format of these packets depends on whether they use IPv4 or IPv6.
Understanding IPv4 and IPv6
IPv4
IPv4 (Internet Protocol version 4) was introduced in 1983 and is still widely used today. It follows a simple format with four sets of numbers separated by dots, like this:
IPv4 is a 32-bit system, meaning it can create about 4.3 billion unique IP addresses. At first, this seemed like plenty. But over time, as more devices connected to the internet—smartphones, computers, smart TVs, and even smart refrigerators—the number of available addresses started running out.
IPv6
To solve this, IPv6 was introduced. It uses a 128-bit system, meaning it can support an almost unimaginable number of addresses—a 39-digit number!
IPv6 looks different from IPv4. Instead of just numbers, it uses both numbers and letters, separated by colons. Here’s an example:
Why IPv6 is Better?
Besides providing more IP addresses, IPv6 also has other benefits:
Better security – It keeps data safer with better encryption and authentication.
Better privacy – It makes it harder for others to track users online.
More efficient communication – It speeds up data transfer by making routing more efficient.
IPv4 and IPv6 Work Together
Even though IPv6 is better, many systems still use IPv4. This means both versions need to work together. To make sure IPv4 and IPv6 devices can still communicate, special techniques were developed to allow smooth interaction between the two systems.
For now, both IPv4 and IPv6 are being used side by side, but in the future, IPv6 will likely become the standard for all devices.
What happened to IPV5?
You might be wondering—if we have IPv4 and IPv6, why is there no IPv5?
IPv5 was actually never officially released. It was created as an experimental protocol mainly for streaming data, like voice and video. However, it still used 32-bit addressing, just like IPv4. This meant it couldn’t solve the problem of running out of IP addresses.
Because IPv5 wasn’t a long-term solution, it was abandoned, and IPv6 was developed instead. Unlike IPv5, IPv6 provides:
A nearly unlimited number of IP addresses
Better security to protect online communication
More efficient data transfer
That’s why the internet skipped IPv5 and moved straight to IPv6!
Conclusion
The Internet Protocol (IP) is what allows devices worldwide to communicate smoothly. It gives each device a unique address and helps direct data to the right place. IPv4 has worked well for years, but with more devices connecting, IPv6 is needed for the future.
Understanding basics like IP addresses, subnetting, and gateways helps us see how data moves online. As technology improves, networks will become faster, safer, and more efficient. Whether you’re fixing a connection or setting up a system, knowing how IP works is a important skill in today’s digital world.
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