Virtual IP Layer: An architecture for virtually extending IP connectivity

The Internet is nowadays divided into multiple segments with different address spaces such as IPv4, IPv6 and private address. To interconnect such segments, NAT, firewall or similar devices are indispensable in the current Internet. Placing such devices on the Internet unnecessarily complicated the Internet. It is extremely difficult and even impossible to strictly preserve the original end-to-end principle of the Internet. We think that it is still possible to preserve the key feature of the end-to-end principle of the Internet even in the current Internet, by just relaxing this strict principle. To this end, we propose a new Internet architecture, which is called a Virtual IP Layer (VIP) that virtually realizes IP connectivity between hosts that belong to different IP address realms. The virtual IP layer is placed just over the IP layer, and performs the IP address translation in a consistent manner, by applying the label-switching technique to forwarding of IP packets. To verify the feasibility of this architecture, we have applied it to communication between hosts, which belong to different private IPv4 realms, via the global IPv4 address realm (i.e. the Internet), and developed its prototype.