Packet and frame difference

A packet is the PDU - protocol delivery unit at layer 3 (network layer) of the networking OSI model. You may have heard them referred to as ip packets. This is the organization of your data at layer 3

A frame is the PDU of layer 2 (data link) of the OSI model.
At layer 2, packets get encapsulated into frames so that they can be transferred over different media to the end destination. Still the same data...it could be split up differently due to varying window size, but there are a few different details added into the frame header.


a packet is a formatted block of data carried by a packet mode computer network. Computer communications links that do not support packets, such as traditional point-to-point telecommunications links, simply transmit data as a series of bytes, characters, or bits alone. When data is formatted into packets, the bitrate of the communication medium can better be shared among users than if the network would have been circuit switched. By using packet switched networking it is also harder to guarantee a lowest possible bitrate.

In computer networking, a frame is a data packet of fixed or variable length which has been encoded by a data link layer communications protocol for digital transmission over a node-to-node link. Each frame consists of a header frame synchronization and perhaps bit synchronization, payload (useful information, or a packet at higher protocol layer) and trailer. Examples are Ethernet frames and Point-to-point protocol (PPP) frames.


A packet is a group of bits of data. A frame is a place to put a packet.
You can't store a frame -- it is mainly of interest to low level network
hardware. A frame is typically an interval of time. Sometimes, it is the
equivalent region along the length of a wire.

If you look at a very early use of the term "frame" this is clear. In the
RS-232 asynchronous serial line protocol, a packet (though not called
that) is typically 8 bits that represent a byte of data being sent from
one node to another. But on the wire, you have to add a start bit in
front and a stop bit in back. Adding those bits is called "framing." You
will never see the 10 bit sequence stored anywhere - the bits are added on
the fly by hardware. The start and stop bits are not part of any packet.
The time between when the receiver sees the start bit and when the
receiver sees to stop bit, not the 10 bits, is a frame.

In T1, a frame is defined by points in time alone -- no extra bits
involved at all. It's not uncommon on T1 voice lines for the packets to
end up distributed incorrectly among the frames (instead of one packet to
each frame), thus causing individual voice circuits to get messed up.