This read-write enumerated INTEGER (send-receive/receive-only) defines which mode is applied on flow-control-enabled ports, per the description: send-receive both sends and receives pause frames, while receive-only accepts incoming pause frames but never sends them out. Admins use this to control whether a port can actively push back on senders (send-receive) or only respond to being told to pause by upstream devices (receive-only). For example, setting receive-only on a port connected to a device that shouldn't be paused by this switch, but from which the switch still wants to honor incoming pause requests, avoids sending unwanted pause frames upstream.