Am 07.07.2015 um 13:49 schrieb Steven Tardy:
http://www.dlink.com/-/media/Business_Products/DGS/DGS%201210%2048/Manual/DG...
What are the current settings on the switch for: Loopback Detection page 35 STP Global Settings page 38 STP Port Settings page 39
Under STP Global the "forward delay" defaults to 15 seconds... The same delay you're seeing.
Loopback Detection Settings = Disabled
STP Global Settings = Disabled
STP Port Settings = ... it seams to be disabled, I can't edit any of the fields, but "State" is "Enabled" ...