Packet This term is considred by many to correctly refer to a
message sent by protocols operating at the network layer of the OSI
Reference Model. So you will commonly see people refer to [i/IP
Packets[/i]. However, this term is commonly also used to refer
generically to any type of message.
Datagram This term is basically synonymous with packet and is also used to refer to network layer technologie. It is also often used to refer to a message that is sent at a higher level of the OSI Reference Model (more often than packet is).
Frame This term is most commonly associated with messages that travel at low levels of the OSI Reference Model. In particular, it is most commonly seen used in reference to data link layer messages. It is occasionally also used to refer to physical layer messages, when message formatting is performed by a layer 1 technology. A frame gets its name from the fact that it is created by taking higher-level packets or datagrams and "framing" them with additional header information needed at the lower level.
DIFFERENCE BETWEEN PACKET AND FRAME
A frame is a PDU in data link layer. A packet is the PDU at the network layer. A data link header and footer are added to packet to create a frame .
A frame is therefore said to encapsulate a packet.
wikipedia says:
"Reliable packets vs. unreliable datagrams..."
It means that packets are connected with TCP and datagrams with UDP.
Before discussing TCP in more detail, let us discuss the TCP packets themselves. A packet in TCP is called a segment.
How Connection Establish by TCP
A SYN segment cannot carry data, but it consumes one sequence number.
A SYN + ACK segment cannot carry data, but does consume one
sequence number.
An ACK segment, if carrying no data, consumes no sequence number.
The following pic is Data Transfer by TCP.
Datagram This term is basically synonymous with packet and is also used to refer to network layer technologie. It is also often used to refer to a message that is sent at a higher level of the OSI Reference Model (more often than packet is).
Frame This term is most commonly associated with messages that travel at low levels of the OSI Reference Model. In particular, it is most commonly seen used in reference to data link layer messages. It is occasionally also used to refer to physical layer messages, when message formatting is performed by a layer 1 technology. A frame gets its name from the fact that it is created by taking higher-level packets or datagrams and "framing" them with additional header information needed at the lower level.
A frame is a PDU in data link layer. A packet is the PDU at the network layer. A data link header and footer are added to packet to create a frame .
A frame is therefore said to encapsulate a packet.
wikipedia says:
"Reliable packets vs. unreliable datagrams..."
It means that packets are connected with TCP and datagrams with UDP.
Transmission Control Protocol
TCP is connection-oriented. It establishes a virtual path between the source and destination. All of the segments belonging to a message are then sent over this virtual path. You may wonder how TCP, which uses the services of IP, a connectionless protocol, can be connection-oriented. The point is that a TCP connection is virtual, not physical. TCP operates at a higher level. TCP uses the services of IP to deliver individual segments to the receiver, but it controls the connection itself. If a segment is lost or corrupted, it is retransmitted.Before discussing TCP in more detail, let us discuss the TCP packets themselves. A packet in TCP is called a segment.
How Connection Establish by TCP
A SYN + ACK segment cannot carry data, but does consume one
sequence number.
An ACK segment, if carrying no data, consumes no sequence number.
The following pic is Data Transfer by TCP.
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