Hi Mikem, thanks for reply
Its not port issue or any other isue in disconnect supervision config. Config are ok. Also I’ve changed Fireware to latest one qt-sy-p4-2-20-40qt-lec. Suddenly GW is going to offline and then we can’t PING it or cann’t telnet GW. But If reset the GW, its works again fine for some times. Then happen same thing again.