Connect and share knowledge within a single location that is structured and easy to search. However Datagram can also be used in a more general sense and refer to other layers link :. A self-contained, independent entity of data carrying sufficient information to be routed from the source to the destination computer without reliance on earlier exchanges between this source and destination computer andthe transporting network.
Frames are units of data in the Link Layer e. Wifi, Bluetooth, Ethernet, etc. A packet is a general term for a formatted unit of data carried by a network. It is not necessarily connected to a specific OSI model layer. For example, in the Ethernet protocol on the physical layer layer 1 , the unit of data is called an "Ethernet packet", which has an Ethernet frame layer 2 as its payload.
But the unit of data of the Network layer layer 3 is also called a "packet". A frame is also a unit of data transmission. In computer networking the term is only used in the context of the Data link layer layer 2. Another semantical difference between packet and frame is that a frame envelops your payload with a header and a trailer, just like a painting in a frame, while a packet usually only has a header.
But in the end they mean roughly the same thing and the distinction is used to avoid confusion and repetition when talking about the different layers. Actually, there are five words commonly used when we talk about layers of reference models or protocol stacks : data , segment , packet , frame and bit. Thus PDU gives an abstract idea of the data packets. The PDU has a different meaning in different layers still we can use it as a common term.
When we come to your question, we can call all of them by using the general term PDU , but if you want to call them specifically at a given layer:. Here is a diagram, since a picture is worth a thousand words:. A frame is the chunk of data sent as a unit over the data link Ethernet, ATM. A packet is the chunk of data sent as a unit over the layer above it IP. If the data link is made specifically for IP, as Ethernet and WiFi are, these will be the same size and packets will correspond to frames.
A packet is the unit of data that is routed between an origin and a destination on the Internet or any other packet-switched network. Each of these packets is separately numbered and includes the Internet address of the destination.
The individual packets for a given file may travel different routes through the Internet. When they have all arrived, they are reassembled into the original file by the TCP layer at the receiving end.
A frame is usually transmitted serial bit by bit and contains a header field and a trailer field that "frame" the data. Some control frames contain no data. It is continuously updated or refreshed from a frame buffer, a highly accessible part of video RAM. The format in which data frames are constructed depends on the particular data-link layer protocol being used. Each particular local area network LAN or wide area network WAN data-link protocol has its own method of framing data for transmission over the network or telecommunications line.
Frames can be fixed-length or variable-length, and have addressing information for multipoint connections or no addressing information for point-to-point connections. They can also have error correction, as in X. The following points give you a brief about the various fields of a frame. A packet can be any small block of data sent across a packet switched network.
The term derives from character-oriented protocols that are added special start-of- frame and end-of-frame characters when transmitting packets.
A packet is the protocol data unit used in the network layer. As the primary function of the Network layer is to deliver a packet from one logical address IP address to another. A packet is a solitary unit of data interchanged between two devices on a network. The router uses IP packet header to send packets through the network from source to destination.
When dealing with connectionless network, data is partitioned into small parts known as packets to transfer it over a network that are multiplexed into high range intermachine connections. A packet, which generally contains only a few hundred bytes of data, carries identification that enables the network hardware to know how to send it to the specified destination.
For example , an enormous file is broken into many packets and then transmitted across the network one at a time. The network hardware conveys the packet to the certain destination, where a software regathers them into a single file again.
Frames and Packets function as protocol data units utilized on the different layers of OSI.
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