TCP 與 UDP 協定分析 第 22 組 b 陳贊羽 b 馬家驤 b 林怡賢 b 王奕棠

TCP Overview (1/2) TCP creates "segments" or "user datagrams" by taking the information from the Application layer and adding a header to it. Since TCP is responsible for Port to Port addressing, it uses a 16bit process port to identify who it wants to talk to. This means that TCP deals with program to program, not machine to machine. TCP creates "segments" or "user datagrams" by taking the information from the Application layer and adding a header to it. Since TCP is responsible for Port to Port addressing, it uses a 16bit process port to identify who it wants to talk to. This means that TCP deals with program to program, not machine to machine.

TCP Overview (2/2) It works by opening up a stream or virtual circuit between the two ports, which begins by alerting the receiver to expect information and ends by an explicit termination signal. Since every segment received is answered with an acknowledge, TCP is a reliable stream delivery service. This just means that the information is "guaranteed" to arrive, or an error will be returned. It works by opening up a stream or virtual circuit between the two ports, which begins by alerting the receiver to expect information and ends by an explicit termination signal. Since every segment received is answered with an acknowledge, TCP is a reliable stream delivery service. This just means that the information is "guaranteed" to arrive, or an error will be returned.

TCP Header (1/9)

TCP Header (2/9)  Source Port Address (16)-The address of the application that is generating the segment.  Destination Port Address (16)-The address of the application that will receive the segment.

TCP Header (3/9)  Sequence Number (32)-Position of data in the original data stream (if it has been split).  Acknowledge Number (32)-Acknowledges the acceptance of data from the other device.

TCP Header(4/9)  H Len (4)-Header Length. Number of 4 byte words used in header (0-60 bytes).  reserved (6)---reserved for future use--

TCP Header (5/9)  [CONTROL]: URG (1)-Urgent Bit validates the Urgent Pointer field.  [CONTROL]: ACK (1)-Acknowledge Bit, set if the Acknowledge Number field is being used.

TCP Header (6/9)  [CONTROL]: PSH (1)-Push Bit tells the sender that a higher throughput is required.  [CONTROL]: RST (1)-Reset Bit resets the connection when there's conflicting sequence numbers.

TCP Header (7/9)  [CONTROL]: SYN (1)-Sequence Number Synchronization. Used in 3 types of segments: connection request, connection confirmations (with ACK) and confirmation termination (with FIN) in 3 types of segments: terminal request, terminal confirmation (with ACK) and acknowledgement of terminal confirmation (with ACK).

TCP Header (8/9)  [CONTROL]: FIN (1)-Used with SYN to confirm termination of connections.  Window Size (16)-Defines the size of the "sliding window.“  Checksum (16)-Error checking and correction.

TCP Header (9/9)  Urgent Pointer (16)-Valid if URG is set, it defines the end of the urgent data.  Options and Padding (variable)-Additional information for alignment purposes (see below).

TCP connection

TCP Disconnection

TCP Functionality (1/2)  Streams. TCP data is organized as a stream of bytes, much like a file. The datagram nature of the network is concealed.  Reliable delivery. TCP will arrange for retransmission if it determines that data has been lost.

TCP Functionality (2/2)  Network adaptation. TCP will dynamically learn the delay characteristics of a network and adjust its operation to maximize throughput without overloading the network.  Flow control. TCP manages data buffers, and coordinates traffic so its buffers will never overflow. Fast senders will be stopped periodically to keep up with slower receivers