Understanding Packets and Frames: How Data Travels Across a Network
When data is sent across a network, it doesn’t move as one large chunk. Instead, it’s broken down into smaller pieces called packets and frames, which help ensure efficient and reliable communication between devices.
Packets vs. Frames: What's the Difference?
Think of frames as envelopes within envelopes. A frame encapsulates data but does not contain IP addresses—making it useful only within a local network. A packet, on the other hand, carries critical addressing information like Source IP, Destination IP, Time to Live (TTL), and Checksum to ensure it reaches the correct destination across networks.
TCP and the Three-Way Handshake
The Transmission Control Protocol (TCP) is a reliable way to send data, ensuring that every packet arrives intact. It establishes a connection through a three-way handshake:
- SYN – The sender requests a connection.
- SYN/ACK – The receiver acknowledges the request.
- ACK – The sender confirms, and the connection is established.
TCP’s error-checking and retransmission make it great for applications requiring accuracy, such as web browsing and email, but it comes with extra overhead.
UDP: Speed Over Reliability
In contrast, the User Datagram Protocol (UDP) is a connectionless protocol that focuses on speed rather than reliability. It doesn’t guarantee delivery, making it ideal for real-time applications like video streaming and gaming. The trade-off? No retransmissions if data is lost.
Ports: The Gateways for Communication
To wrap things up, I explored ports, which act as entry points for different types of network traffic. There are 65,536 ports, with commonly used ones assigned to specific protocols—like HTTP (port 80) and DNS (port 53). Understanding ports is crucial for managing network security and performance.
What’s Next?
With a solid foundation in packets, frames, and protocols, the next module is Extending Your Network—learning how devices communicate across larger infrastructures.
