second floor laundry drain

[possum]

Im putting second floor laundry room. What size does the drain need to be . Do I need a trap what kind how fare from opening should the trap be> thanks any help would be grate!!

[Terry]

http://terrylove.com/images/washer_rough_b.jpg

The washer drain will be 2", the vent can be 1.5"
The vent needs to be within five feet of the washer p-trap.