Software load balancing fail-over vs hardware

view story

http://serverfault.com – Please correct me, but my understanding is that with software load balancing a service must be run on each server while there is one DS that notifies the other servers that a server has gone down and that they should consume that servers load. With hardware load balancing what happens in a fail-over? Could someone explain? Is there advantages with using hardware load balancing when it comes to fail-over, or is there advantages with software? Or do they both have their pros and cons? (HowTos)