Packet and Frame

Generally, data packets sent from the data link layer are called frame, and the address is the link layer address, such as MAC address. packets sent from the network layer are called packet, and the address is the network layer address, such as IP address; the packet sent by the transport layer is called a segment, and the address is the transport layer address, such as the TCP port number.

Data encapsulation process: 1. Data 2. Segment 3. Packet 4. Frame 5.bit

Protocol: 1. Application-session (represen layer is in the middle) Layer 2. transprot Layer 3. Network Layer 4. data link layer 5. Physical Layer

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Difference between datasync and packet:

Datagrams-transmission units (such as IP addresses) at the network layer ). A datax may be compressed into one or more packages and transmitted at the data link layer.

Packet (data packet) is the basic unit of encapsulation. it traverses the decomposition surface at the network layer and data link layer. A packet is usually mapped to a frame, but there are also exceptions: when the data link layer is split or several packages are merged into a frame.

Two-layer PDU are called frame; IP is called packet; TCP is called segment; UDP is called datasync.

The data and control information transmitted at each layer of the OSI reference model has multiple formats. Common information formats include frames, packets, datagram, segments, messages, elements, and data units. Information exchange occurs between peer-to-peer OSI layers. Control Information is appended to data at each layer of the source machine, while each layer of the target machine is connected to the received information for analysis, and remove the control information from the data.

The information units are described as follows:

A frame is an information unit. Its starting point and destination point are both the data link layer.

A packet is also an information unit. Its starting and destination are the network layer.

A datagram is usually a unit of information at the network layer where no network service is connected to the start point and destination.

Segment (segment) usually refers to the starting point and destination are the information units of the transport layer.

Message refers to the Information Unit where both the origin and destination are at or above the network layer (often at the application layer.

An element (cell) is a fixed-length information. Its starting point and destination are data link layers. Elements are usually used in asynchronous transmission mode (ATM) and multi-region Data Service (smds) Switching environments.

Data Unit refers to many information units. Common data units include SDU and PDU ).

SDU transmits information between two layers on the same machine. PDUS send information on each layer of the machine to the corresponding layer on the receiving machine (equivalent for intercommunication ).

Packet and Frame