A packet is a small chunk of data transmitted across a network. Instead of sending a large message all at once, networks break data into packets so they can be routed efficiently and reliably. Each packet contains a header with routing information and a payload with actual data. Routers examine packet headers to determine the best path across networks. Packets may arrive out of order or take different routes depending on congestion. Packet based communication allows the internet to scale globally across millions of devices. Applications rely on packets without needing to know the underlying details.
Key Characteristics
Packets include source and destination IP addresses, ports, and protocol identifiers. Protocols like TCP add reliability by ensuring packets are acknowledged and retransmitted if lost. Others, like UDP, prioritize speed over reliability. Tools like packet sniffers help developers inspect raw network traffic during debugging. Understanding packet flow is critical when diagnosing latency, connectivity issues, or security breaches.