What Is The Proper Etiquette For A Birthday Dinner?

My birthday is coming up in a few weeks and one of my favorite things to do is have a birthday dinner. I love getting all of my friends together in one place and sharing a meal. However, I've just got one question...

Who pays?

Whenever I've been invited out to dinner for a friends birthday (to a restaurant) I always assume that I've got my own food and drinks and that I should help pitch in for the birthday girl/boy's dinner. Sometimes the birthday girl or boy will flip the bill for the drinks but I usually pay for my own food. And I'm TOTALLY fine with that! When you've got 20 people at a dinner there is NO WAY I expect the birthday person to pay for everyone! Right?

But.... are there people who think that if they are invited to a restaurant for a birthday dinner that it's paid for? And how do you communicate if it is or isn't?? This is the stuff that seriously stresses me out when I start planning these things LOL

And does it depend on place? So, if I had a party at a bowling alley I think it is normal that the birthday person pay for the bowling and some pizzas and beer. Normal, right? Or if I had a party at my house then it is normal that I provide all the stuff, right? BUT what is the protocol for dinner at a restaurant??

NEED YOUR INPUT!