Most internet connections are “dynamic IP address connections” this means that you'll get a different IP each time you connect to the internet. “Reconnect” means that you internet connection gets disconnected and connected afterwards. If you have a dynamic IP address connection (most DSL connections) you will get a new IP.
Many hoster use an IP-block to force you to wait a certain time after each download. By changing your IP address, you can bypass this limitation. Please note, that this might conflict with the hosters tocs.
Every ISP and every router works different. So the reconnect methods are different, too. The JD Team is working day and night to create an automated router detection.