I am unable to understand the logic behind the following:-

The maximum number of points of intersection of 6 circles is^{6}P_{2}= 30. I am unable to understand why are we using permutations. Maximum points of intersection of 2 circles is 2. So isn't the question about selecting 2 circles from 6 circles and the solution be^{6}C_{2}= 15. Isn't this a question of combinations ? Where am I making an error ? What is the logic behind the rule ? Request advice on the above.

Thanks in advance !