When people say "tank" in Pathfinder, it irks me. I'm an old Everquest player. I know what a MMO tank is. Fighter has NEVER been that tank. Pathfinder's Fighter is a melee DPS.
It isn't even a "you soak damage" kind of melee, its actually a damage avoidance type. How could I think so? Easy, because the fighter can stack on armor and shield and enchantment bonuses to both. If a fighter gets serious about AC, there are very few classes that can equal them. And those classes that can? They have to make some serious sacrifices to do it. Fighter just switches to a single handed weapon and a heavy shield. Done. If they don't find a sufficiently enchanted shield it means sacrificing a +1 from his weapon to get a decently defensive shield. The soak damage guy is the barbarian, and he's only slightly ahead of the fighter for HP and slightly behind in AC.
Or a fighter can concentrate on doing DPS and raise their damage potential at the cost of AC. Lots of builds do this and quite frankly the payoff is huge.
Lots of people say that fighter is a feat monkey. Well, its true, but it kind of short changes the fighter. The really outstanding abilities of a fighter are actually Weapon Training and Armor Training. Fighter gets full BAB, is heavily induced to use Strength as its primary stat, and can stack on feats to raise their to hit. So can every other full BAB class. Weapon Training gives the fighter that extra umph that makes them superior to other similar classes. Armor training also relaxes the restrictions that everybody else has to pay attention to. Extra AC from dex, less skill penalties, and full movement. I hate a lot of the fighter archatypes because they trades away some of the best abilities fighters get for subpar specialized abilities that are just lacking.
Anyways, back to 'Tanks'. What makes a tank is an ability to force things to attack you. 4th edition D&D has that. Pathfinder has a spell that does that. Fighters don't get it at all. Fighters are not Tanks. If you are making a 'tank' for your...
I would argue that drawing aggro is a way to tank, but is not the only way to tank. A tank reduces the incoming damage for the squishies, whether that is by drawing aggro, debuffing the enemy offence, or providing barriers/temp hp. Aggro tanking is generally the simplest because it works well with combat healers: a lot of tanking is ablative, and hit point healing restores what an aggro tank needs to keep tanking.
I have a mesmerist I enjoy a lot in the tanking role, as both a debuff and aggro tank. Pure aggro tanking is often difficult in PF because how healing works is not balanced for dedicated tanks. But forcing an opponent in a specific direction while they're at -7 to hit is still a noticeable defensive aid.