SackOpts
Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2
HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
| Data type | Range | Default value |
|---|---|---|
REG_DWORD |
0 | 1 |
1 |
Description
Enables and disables the Selective Acknowledgment (SACK) feature of Windows Server 2003 TCP/IP. SACK is specified in RFC 2018, TCP Selective Acknowledgement Options.
SACK is an optimizing feature that lets you acknowledge receipt of individual blocks of data in a continuous sequence, rather than just the last sequence number. The recipient can tell the sender that one or more data blocks are missing from the middle of a sequence, and the sender can retransmit only the missing data.
| Value | Meaning |
|---|---|
0 |
Disables SACK. |
1 |
Enables SACK. |