Tax Rules vs Supplier Tax Classification

Good Day,

I am new to EBS tax and would like to understand the difference between setting up the tax classification code at supplier level and creating tax rules.

We are currently using 12.1.3, upgrading to 12.2 later this year.

We currently have no tax classification code at supplier level and our tax is calculated using the tax rules that we have set up. Our tax department would like us to investigate having the tax driven from the supplier.

I dont understand the relationship between the tax at supplier level versus the tax rules, do we still need rules set up if we have the classification code at supplier level?