Tcp1323Opts
Tcp1323Opts
HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
http://technet.microsoft.com/en-us/library/cc757402(v=ws.10).aspx
Windows 2003
http://support.microsoft.com/default.aspx?scid=kb;en-us;912222
Data type | Range | Default value |
---|---|---|
REG_DWORD | 0 | 1 | 2 | 3 | 3 |
Description
Specifies whether TCP uses the timestamping and window scaling features described in RFC 1323, TCP Extensions for High Performance.
Window scaling permits TCP to negotiate a scaling factor for the TCP receive window size, allowing for a very large TCP receive window of up to 1 GB. The TCP receive window is the amount of data that the sending host can send at one time on a connection.
Timestamps help TCP measure round trip time (RTT) accurately in order to adjust retransmission timeouts. The Timestamps option provides two timestamp fields of 4 bytes each in the TCP header, one to record the time the initial transmission is sent and one to record the time on the remote host.
This entry is a 2-bit bitmask. The lower bit determines whether scaling is enabled; the higher bit determines whether timestamps are enabled. To enable a feature, set the bit representing the feature to 1. To disable a feature, set its bit to 0.
Value | Meaning |
---|---|
0 (00) | Timestamps and window scaling are disabled. |
1 (01) | Window scaling is enabled. |
2 (10) | Timestamps are enabled. |
3 (11) | Timestamps and window scaling are enabled. |