Hi @s25pacct 

Thanks for posting in our business forum.

s25pacct wrote

  @Clive_A Thank for the quick reply.

Re:If a port has been mirrored already, it cannot be mirrored again
I understand this part and I have confirmed ports 5,6,7,8 was not mirrored (in earlier reply to your question that maybe they already mirrored and how I confirmed).
I basically double checked by going into every single ports in the configuration menu to double confirmed this as indicated in earlier replies.

 

Furthermore if ports are being mirrored elsewhere, the status information in the management console would've showed multiple "eye" icons for different monitoring ports.

I checked it with the dev team and got a reply. This is expected to be normal. 1/3/5/6/7/8 and 2/4/9/10/11/12 are separated. I don't get more details for the reason why but it seems to be the chipset or other reason.