TCP (Transmission ControProtocol) Transmission Control Protocol is a connection-oriented, reliable, byte stream-based transport layer protocol.
Detailed tcp packet formatA TCP packet is a data unit transmitted by the TCP layer, also called a segment.
TCP message header format
Source port number (2 bytes):
D5 df(54751)
Destination port number (2 bytes):
22 b8 (8888)
The source port number and the destination port number in the TCP header uniquely identify a TCP connection with the source IP address and the destination IP address in the IP datagram.
Serial number (4 bytes):
37 59 56 75
Used to identify the data byte stream sent by the TCP originator to the TCP receiver.
Confirm serial number (4 bytes):
Since the message is a SYN message, the ACK flag is 0, so there is no confirmation sequence number (the acknowledgment sequence number is valid when the ACK flag is 1)
Once the connection is established, the value will always be sent (same ACK flag)
Head length (4 digits): packet header length (unit: bit) / 32
1000 (converted to decimal 8, 8, * 32 / 8 = 32, the length of the message header is 32 bytes)
This field exists because the length of the optional field in the TCP header is variable.
The header does not contain any optional fields and the length is 20 bytes; the maximum value that can be represented by 4 bits is 1111, which is converted to 10, 15*32/8 = 60, so the maximum length of the header is 60 bytes.
Flag position (12 digits):
0000 00010010
Reserved:
000~ ~~~~~~~~
ECN (Explicit Congetsion NoTIficaTIon):
~~~0 ~~~~~~~~ = N / NS / Nonce Sum: Effectively eliminate potential ECN abuse, RFC 3540
~~~~ 0~~~~~~~ = C / CWR(CongesTIon Window Reduced): Congestion window reduction flag
~~~~ ~0~~~~~~ = E / ECE / ECN-Echo: ECE / ECN logo
ControBits:
~~~~ ~~0~~~~~ = U / Urgent: Emergency Point Validity Sign
~~~~ ~~~1~~~~ = A / Acknowledgment: Confirm the serial number validity flag. Once a connection is established, the flag is always set to 1, that is, in addition to requesting the establishment of a connection message (only the Syn flag is set) For 1), the flag for all other messages is always 1
~~~~ ~~~~0~~~ = P / Push: Push flag (receiver should submit the segment to the application layer as soon as possible)
~~~~ ~~~~~0~~ = R / Reset: Reset connection flag
~~~~ ~~~~~~1~ = S / Syn: Synchronization number sign
~~~~ ~~~~~~~0 = F / Fin: Transfer data end flag
Window size (2 bytes): TCP flow control is controlled by the declared window size at each end of the connection (receive buffer size)
20 00 (00100000 00000000) = 8192
Since the maximum positive integer that 2 bytes can represent is 65535, the maximum window size is 65535.
Checksum (2 bytes): check and overwrite the entire TCP segment; mandatory field, calculated by the sender, and verified by the receiver
2e 2f
Emergency pointer (2 bytes): When the Urgent flag is set to 1, the emergency pointer is valid.
00 00
Optional field (0 - 40 bytes):
BLPS laser safety protective device is designed for personal safety used on hydraulic bender.
The dynamic test technology it used has passed the Type 4 functional safety assessment by TUV, and get the national invention patent. The product reaches the advanced technological level of similar products.
BLPS laser safety device provides protection zone near the die tip of the bender to protect fingers and arms of the operator in close to the upper mold die tip. It is the most effective solution so far to preserves the safety and productivity of the bender.
Press Brake Protection,Laser Guarding Device,Press Brake Guarding Systems,Press Brake Guarding
Jining KeLi Photoelectronic Industrial Co.,Ltd , https://www.sdkelien.com