NACK vs. ACK? When to use one over the other one? 24 Personally I don't even feel that there is a need for ACK It's faster if we just send NACK (n) for the lost packets instead of sending an ACK for each received packet So when which situations would one use ACK over NACK and viceversa?
Why need Ack flag if we already have ack number in TCP The ACK flag indicates that the Acknowledgment Number field is significant, ie containing a meaningful value When a socket connection has already been established that is nearly always the case, but it isn't while a connection is being established Acknowledgment Number: 32 bits If the ACK control bit is set this field contains the value of the next sequence number the sender of the segment
Window Size and ACK Number - Network Engineering Stack Exchange Copy-pasting from my lecturer's slides: • Receiver indicates the window size is 3000 • Transfer goes ahead • Acknowledge every 3000 bytes • Receiver increases window size to 4000 • 4000 bytes
Why the TCP client havent receive the ACK response, it send the FIN . . . If the receiver doesn't receive data, it will send a duplicate ACK to the sender So the sender waits for a time and if it doesn't receive acknowledgment of the FIN or data within this time, or if it receives a duplicate ACK, it will retransmit the packets
Why does a pure ACK increment the sequence number? I cannot figure out why a pure ACK will increment the sequence number of the sending host by 1 when the TCP segment contains only a header, such as in the third segment in a three-way handshake for establishing a TCP connection
Why is the last ACK needed in TCP four way termination The question of why the last ACK is required is just that nay FIN only means that the sender of the FIN is done sending, and it must still be open to receive more segments, and it must resend any unacknowledged segments Each side is a peer (client server is an application concept), and both sides must agree that everything is done