Hello Guys,
thanks a lot for you hints and recommendations. Unfortunately, all those steps were unsuccessfully taken into consideration.
What is not mentioned in the different documentations as well as configuration guide I read was:
If Using a Fiber Port (the dummy Port, where no cable is connected) for the Mirroring, make sure the GBIC is inserted.
I donāt know how I came to the following idea, āonce I inserted the GBICā to that port, I was able to get the traffic over GRE.
It would be great if this were documented in the configuration guide.
Nevertheless, I thank you all for your toughs.
Regards
Gradelain