Hello Alexandr,
Based on the product description and switch architecture I would say that those 6 ports are 4*10GE and 2 rear VIM slot ports. Two last from the front 4*10GE could be used as alternate stacking ports and rear VIM ports are "native stacking", but main point here is that all six ports are connected to the same and common chipset's warpcore. Most of all that is why we see diagnostic test for all 6 ports together. If you need more detailed info please raise a GTAC case.
Best Regards,
Nikolay