Network data is organized into units that different layers understand. An IP packet and a link-layer frame are related containers, but they describe different portions of the communication path.
How the pieces connect
A network layer arranges addressing and routing across interconnected networks. A local link layer carries data between participants on a particular medium. Additional headers provide information needed at each boundary. Encapsulation lets one layer carry another layer's data without forcing every piece of equipment to interpret the complete application conversation.
An everyday example
A message traveling from a laptop to a remote service can cross wireless, wired, and other network segments. The local framing can change along the route while higher-level communication continues. The laptop's adapter reports information about its own link, not a complete inventory of every segment the message eventually traverses.
Reading the information in context
Packet size, link overhead, retransmission, and congestion can influence useful throughput. Counting one type of unit does not automatically describe how much application data was delivered. The library does not capture traffic or ask readers to share packet traces. Its aim is to explain why terms from different layers should not be used as interchangeable measures of a connection.
Network & Wi-Fi
Note these before you change anything
Useful facts to have to hand while reading about packets, frames and the local link.
- Adapter name and driver version
- Whether other devices on the same network work
- IP configuration shown in the system's network details
- Power-saving settings on the adapter
Network & Wi-Fi: Sending data (simplified; replies return the same way)
- Applicationopens a connection
- Network stackTCP/IP and name lookup
- Adapter driverWi-Fi or Ethernet
- Network adapterradio or port
- Routerand the wider network
