Frames
The PDU (protocol data unit) @ transport layer (e.g. TCP or UDP) is called as 'segment' .
A PDU (Protocol Data Unit) is defined by which layer it is in. In the physical layer and network layer, it is synonymous with the packet, in the data link layer, it is the frame. In the transport layer, it is a datagram for UDP. A datagram holds one or more PDU's, as it is the basic unit of transferring information via packet switching.
The PDU at the Network layer is referred to as a packet. A PDU at the Data Link Layer is referred to as a frame.
The Layer for the TCP Protocol Data Unit (PDU) is called the Transport Layer. In the OSI model, the Transport Layer is responsible for end-to-end communication, ensuring reliable data transfer, error correction, and flow control. TCP (Transmission Control Protocol) operates at this layer, providing a connection-oriented service for transmitting data between applications.
manages the data transport between the processes running on each end host
Datagrams TCP/IP layer 4 PDU's are called segments...
A Protocol Data Unit (PDU) is a unit of data specified in a protocol of a given layer of the OSI model. Each layer has its own PDU: at the Application layer, it's called a message; at the Transport layer, it's a segment (or datagram in UDP); at the Network layer, it's a packet; at the Data Link layer, it's a frame; and at the Physical layer, it's a bit or symbol. These PDUs help in managing and encapsulating data as it traverses through the layers of the OSI model.
Application layer: Data Presentation layer: Data Session layer: Data Transport layer: Segment (TCP) or Datagram (UDP) Network layer: Packet Data Link layer: Frame Physical layer: Bit
Segements
What is a PDU? corruption of a frame during transmission data reassembled at the destination retransmitted packets due to lost communication a layer specific encapsulation
In networking, PDU means "protocol data unit", and it is the generic name of the "packets" of data used at different levels of the network. Using the numbering of the OSI layers: At layer 2, the PDUs are called "frame". Example: An Ethernet frame, a frame-relay frame. At layer 3, the PDUs are called "packets". Example: An IP packet. At layer 4, the PDUs are called "segments". Example: A TCP segment, a UDP segment.
PDU (protocol data units) -Yuriy-