KeepAlive configuration
The transmission of TCP KeepAlive messages verifies if an idle TCP connection is still active. Since version 1.0.47 of the TwinCAT TCP/IP Server (TF6310), the KeepAlive configuration of the Windows operating system is used, which can be configured via the following registry keys:
The following documentation is an excerpt of a Microsoft Technet article.
KeepAliveTime
HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Data type | Range | Default value |
|---|---|---|
REG_DWORD | 0x1–0xFFFFFFFF ( milliseconds ) | 0x6DDD00 ( 7,200,000 milliseconds = 2 hours ) |
Description
Determines how often TCP sends keep-alive transmissions. TCP sends keep-alive transmissions to verify that an idle connection is still active.This entry is used when the remote system is responding to TCP. Otherwise, the interval between transmissions is determined by the value of the KeepAliveInterval entry. By default, keep-alive transmissions are not sent. The TCP keep-alive feature must be enabled by a program, such as Telnet, or by an Internet browser, such as Internet Explorer.
KeepAliveInterval
HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Data type | Range | Default value |
|---|---|---|
REG_DWORD | 0x1–0xFFFFFFFF ( milliseconds ) | 0x3E8 ( 1,000 milliseconds = 1 second ) |
Description
Determines how often TCP repeats keep-alive transmissions when no response is received. TCP sends keep-alive transmissions to verify that idle connections are still active. This prevents TCP from inadvertently disconnecting active lines.