You can manage servers remotly either via
1) KVM switch (Its already explained in link which u posted)
2) Via DRAC ( specific for Dell) , ILO ( HP) , IBM also have something ( i forgot the name) , These are interface cards which is attached to the serv. You just need to plug seprate serial cable to that card/port.
These card have separate network, memory, power etc. Its independent of the Production network
While configuring DRAC u have to give it own IP , you can access it via web-browser http://ip-of-drac or access by dns name ( if its added in DNS)
http://en.wikipedia.org/wiki/Dell_DRAC
Configuration is easy. Some of them are configured during boot up i.e BIOS. boot will show which keys needs to be pressed to configure ILO/DRAC. It will ask you IP, name , subnet etc . Thats all