Parameter problem when navigating a page using next/link

[D-Trick]

For example, there is the address /server/[id.

Move through next/link.
"ctx.req.query.id"

Just type the address in the browser.
"ctx.req.params.id"

Depending on the movement above, it is entered into query and params.

Can you explain why?
And is there a simple code to distinguish this?