CRS-109 Port Mirroring question

Hello Guy’s , I am kind of new to the Mikrotik and I am trying to make a mirror of everything that is incoming from or outgoing to the internet to a certain port.
My master switch port is Ether2 and my internet is on Ether1.
Basically this :


internet <---- PORT 1 SLAVE OF PORT 2 —> Mikrotik
|
|
PORT 8


Following the wiki, the configuration would be this if I understand properly :

/interface ethernet switch
set ingress-mirror0=ether8 egress-mirror0=ether8

/interface ethernet switch port
set ether1 ingress-mirror-to=mirror0 egress-mirror-to=mirror0

But when I put the computer on the port 8, all I can see there is some normal broadcasting. nothing more.
What is it that I understand wrong ?

Anybody can help me on that ?

Cheers,