What indicates the receipt of a packet in TCP communications?

What indicates the receipt of a packet in TCP communications?

• A. Post-Connection SYN
• B. HTTPort
• C. Super Network Tunnel
• D. ACK bit

Answer: (D)

In TCP, receipts are confirmed through an acknowledgment mechanism using the ACK flag in the TCP header. When a receiver gets a segment, it sends back a segment with the ACK bit set, signaling that the data arrived and indicating the next expected byte with the acknowledgment number. This is how the sender knows which data has been successfully received and can advance its sending window. Note that during the initial three-way handshake, a segment may carry both SYN and ACK flags, but in normal data transfer, the presence of the ACK bit is the defining signal that a packet has been received. The other options don’t represent an acknowledgment mechanism in TCP.

In TCP, receipts are confirmed through an acknowledgment mechanism using the ACK flag in the TCP header. When a receiver gets a segment, it sends back a segment with the ACK bit set, signaling that the data arrived and indicating the next expected byte with the acknowledgment number. This is how the sender knows which data has been successfully received and can advance its sending window. Note that during the initial three-way handshake, a segment may carry both SYN and ACK flags, but in normal data transfer, the presence of the ACK bit is the defining signal that a packet has been received. The other options don’t represent an acknowledgment mechanism in TCP.