TCP ACK Frequency

ScottMac

Moderator<br>Networking<br>Elite member
Mar 19, 2001
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"Ack" is not something done by time period, it's done to acknowledge that a complete chunk of data (frequently " I have received blocks up to block number ##" because TCP can ACK more than one block at a time) has been received.

You can hard set the "window," as a maximum value but it is negotiated at the beginning of the TCP session to the largest value that both sides can agree to.

If there's no ACK, then the "next" block(s) of data will not be sent.

If you need unacknowledged transmission, then you'd usually use UDP instead of TCP.

What is it you're trying to accomplish?
 
Nov 26, 2005
15,194
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thanks for the reply, but first of all, im newb at well just about everything...

what the difference between setting it from "1" to "0" ???
 

jlazzaro

Golden Member
May 6, 2004
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MS TCP Acknowledgment Behavior

TcpAckFrequency is a new registry entry in Microsoft Windows XP and Microsoft Windows Server 2003 that determines the number of TCP acknowledgments (ACKs) that will be outstanding before the delayed ACK timer is ignored.

If you set the value to 1, every packet is acknowledged immediately because there is only one outstanding TCP ACK as a segment is just received. The value of 0 (zero) is not valid and is treated as the default, 2. The only time the ACK number is 0 is when a segment is not received and the host is not going to acknowledge the data.