What is the significance of a value in the window field of an incoming TCP segment?

The window field contains a 16-bit number that indicates how many bytes a TCP receiver is able to buffer. This is used in the TCP flow control mechanism described later. If the window field is zero, the TCP sender should not send any more data until it has received a TCP segment with a window larger than zero.

What is the significance of the following TCP header fields sequence number reserved bits window size checksum urgent pointer?

It indicates how much data in the current segment counting from the first data byte is urgent. Urgent pointer added to the sequence number indicates the end of urgent data byte. This field is considered valid and evaluated only if the URG bit is set to 1.

What is the purpose of SYN ACK and FIN flag bits in the TCP header?

Security for TCP Headers with SYN and FIN Flags Set The SYN flag synchronizes sequence numbers to initiate a TCP connection. The FIN flag indicates the end of data transmission to finish a TCP connection. Their purposes are mutually exclusive.

What is the use of window size field in TCP header?

The TCP window size field controls the flow of data and is limited to 2 bytes, or a window size of 65,535 bytes. Since the size field can’t be expanded, a scaling factor is used. TCP window scale is an option used to increase the maximum window size from 65,535 bytes to 1 Gigabyte.

What is urgent data in TCP?

TCP offers the ability to flag certain bytes of data as “urgent.” This feature allows an application to process and forward any data that must be dealt with immediately, without the data having to sit in the send queue for processing.

What is urgent pointer in TCP header?

This is a 16 bit field in TCP header, its not a flag. It indicates how much data in the current segment counting from the first byte is urgent. It defined the number which must be added to the sequence number to get the number of the last urgent bytes in the current segment.

What is the difference between push and urgent flag?

The gist of the matter is that once you push data on a connection you have to wait for the receiver to get all of it before it gets to the new data. This is where the URG flag kicks in. When you send urgent data, your TCP creates a special segment in which it sets the URG flag and also the urgent pointer field.

What is the use of urgent pointer in TCP header?

The urgent pointer flag in the TCP Flag allows us to mark a segment of data as ‘urgent’, while this urgent pointer field specifies where exactly the urgent data ends. You may also be interested to know that the Urgent Pointer can also be used when attacking remote hosts.

What is the purpose of the receiver’s window?

The Receiver Window (rwnd) is a variable that advertises the amount of data that the destination side can receive. Together, the two variables are used to regulate data flow in TCP connections, minimize congestion, and improve network performance.

What is the purpose of using URG data pointer in a TCP header?

The URG flag is used to inform a receiving station that certain data within a segment is urgent and should be prioritized. If the URG flag is set, the receiving station evaluates the urgent pointer, a 16-bit field in the TCP header.

What is urgent flag in TCP?

Urgent (URG) –Data inside a segment with URG = 1 flag is forwarded to application layer immediately even if there are more data to be given to application layer. It is used to notify the receiver to process the urgent packets before processing all other packets.