gw/conn_pending is a SAP Parameter attribute which is used to control timeout for pending connections information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
When setting up a connection to a gateway, an external program or via a
saprouter, information needs to be exchanged. Until this has happened,
the connection cannot be used and is flagged with CONN_PENDING. If the
data is not exchanged within this time period, the connection is
deleted.
Value 0 deactivates this check.
This check can be performed a maximum of every
See SAP Parameter Documentation for full SAP documentation for this profile parameter.