Question : PoE network card

I need to be able to remotely boot my Server.
what do i need for? How PoE works? Do I need switch PoE?

Answer : PoE network card

Hi POE is not the solution. PoE is used to provide power over the ethernet link rather than giving it power from the traditional power socket. The devices can be anything from phones,to wireless equipments etc...
 
For your solution as suggested by delsof go for a RAC card or there are KVM switches available from companies like Cycaldes which give you this flexibility and other features as well.
Depends on how much you are willing to spend on the solution.