IP v6 is the protocol that might replace the current version 4 created to supply the increasing number of devices connected to the Internet. However, this technology might never be established because of a cheaper technology, called NAT (for Network Address Translation), that gives with one IP v4 number Internet access to an entire subnetwork, like the ones that can be found in a student house or a small company. Using NAT, the old IP v4 routers can work as before, while IP v6 claims for a complete renewal of the Internet infrastructure.
NAT uses the infrequently used source ports numbered above 2000014 to store additional information on the local computer that sends a packet. In TCP/IP, to answer a packet, the couple ([destination IP:Port][source IP:Port]) is simply inverted to build an answer. Therefore, the router will map particular ports ranges to computers on the local network.
A little disadvantage for GPU is that all users behind a NAT router surf with the same IP number and some information is lost on how these computers are interconnected.
Another disadvantage is caused by the dynamic IP that most ADSL providers offer: After a period of 20 hours, the IP number changes. This is a commercial trick to avoid having people provide web services or other server features with these cheap connections15. Every three hours, GPUs touch special websites to update the IP numbers they send in status request. Meanwhile, they might answer status request wrongly. In GPU, we call these nonexistent nodes that arise because of the dynamic IP problem "ghosts"; they are plotted as a wire sphere as well.