Keepalive frames for TCP and ISO-on-TCP connections - STEP 7

Communications modules and network components

ft:publication_title
Communications modules and network components
Product
STEP 7
Version
V20
Publication date
11/2024
Language
en-US
Keepalive frames for TCP and ISO-on-TCP connections

Reference

Making special settings for the PROFINET interface in the "Properties > General >PROFINET interface > Advanced options > Interface options" parameter group

Keepalive frames (only with TCP and ISO-on-TCP connections)

Here, you can set the interval at which keepalives are sent to the partner of a communications connection.

The Ethernet CP is configured for all connection-oriented services so that keepalive frames are sent. This ensures that connections are terminated if one of the communication partners fails and the connection resources are released again. The setting made here applies to all TCP and ISOonTCP connections operated via the CP. A connection-oriented setting is not possible.

Range of values

  • Default setting: 30 seconds

  • Maximum value: see information displayed in the input box

  • Function turned off: 0 seconds

Note

Note that the keepalive mechanism can cause subordinate connections (for example, an ISDN telephone connection) to be maintained even though user data is not actually being transferred. If this is unwanted, proceed according to one of the following alternatives:

  • Disable the keepalive mechanism (interval time = 0).

  • Set the interval so high that the underlying connection is terminated before a keepalive frame is sent when there is no data traffic.