The size of a TCP segment encapsulated by an IP header does not have a fixed size and can vary based on the data being transmitted. However, the maximum size of a TCP segment is typically constrained by the Maximum Transmission Unit (MTU) of the network, which is commonly around 1500 bytes for Ethernet. Given that the IP header is 20 bytes, the maximum TCP segment size would be approximately 1480 bytes if there are no additional headers or options. In practice, the exact size would depend on the TCP header size and any options included.
HTTP
TCP (Transmission Control Protocol) uses a variable header size that typically ranges from 20 to 60 bytes. The standard header size is 20 bytes, which includes fields such as source and destination ports, sequence number, acknowledgment number, and control flags. Additional options can extend the header size, but the maximum size for a TCP packet, including the header and data, can be up to 65,535 bytes.
Both TCP and UDP have origin and destination ports - and that is about all the similarity there is between the two. TCP has several other fields that UDP doesn't have, including window size; a consecutive byte numbering (to figure out where to place a TCP segment in a data stream); the bytes that the other side is expected to send; and others.
2^16 bytes - size of TCP header
The checksum field in a TCP header is used to verify the integrity of the TCP segment during transmission. It checks for errors that may have occurred in the data, ensuring that the segment received is the same as the one sent. The checksum is calculated over the TCP header and the data payload, and the receiver recalculates the checksum to confirm its accuracy. If the checksums do not match, the segment is considered corrupted and is typically discarded.
code bits
It indicates the "number of bytes the device is willing to accept".
window
In the commonly used TCP/IP communications, that would either be a TCP header, or a UDP header.In the commonly used TCP/IP communications, that would either be a TCP header, or a UDP header.In the commonly used TCP/IP communications, that would either be a TCP header, or a UDP header.In the commonly used TCP/IP communications, that would either be a TCP header, or a UDP header.
to enable a receiving host to forward the data to the appropriate application
The internet header padding is used to ensure that the internet ends on a 32 bit boundary. The padding is zero.
The protocol field, in the IP header, identifies what kind of data is in the IP packet - the upper-layer protocol. For example, if the code is 6, that means that the data is a TCP segment.