Frame vs Packet - Difference Between Ethernet Frames and IP Packets
Frame and packet are layer-specific terms. A frame belongs to the data-link layer, while a packet usually refers to the network layer. Packet captures often contain both because one wraps the other.
Key Takeaways
Frames are link-layer units such as Ethernet frames.
Packets are network-layer units such as IPv4 or IPv6 packets.
Segments and datagrams are transport-layer terms.
Understanding the terms helps you read captures precisely.
The short answer
A frame is the unit used on a local link, while a packet is the unit routed between networks. In an Ethernet capture, the IP packet is usually the payload inside the Ethernet frame.
Why terminology matters
Precise language helps avoid decoding mistakes. If you expect an IP packet but your hex starts with MAC addresses, you are probably looking at an Ethernet frame that contains an IP packet.
How layers wrap each other
Application data can be carried by TCP, TCP can be carried by IP, and IP can be carried by Ethernet. Each layer adds its own header before sending bytes to the next layer.
Practical Reference
| Item | Value | Analysis Note |
|---|---|---|
| Frame | Data-link layer | Ethernet II is a common example. |
| Packet | Network layer | IPv4 and IPv6 are common examples. |
| Segment | TCP transport unit | Includes sequence numbers and flags. |
| Datagram | UDP transport unit | Connectionless message unit. |
FAQ
Why do people still say packet analyzer?
Packet analyzer is a common broad phrase even when the tool also decodes frames, segments, and datagrams.
Can a frame contain more than one packet?
A normal Ethernet frame carries one network-layer payload, but tunneling and encapsulation can nest additional packets inside payloads.