L2TP LNS specific information about a specific group interface.
Unlike regular subscriber traffic, that enters the system through
Service Access Points (SAP) on a group-interface,
traffic for PPP subscriber sessions terminated by the LNS function,
enters the system through a plain layer 3 interface;
this traffic is relayed for processing to an L2TP ISA MDA;
it re-enters through an internal LNS group interface;
this entry allows to configure subscriber management parameters for
PPP subscriber sessions.