Mixing Heterogeneous Address Spaces in a Single Edge Network

摘要

The growth of IPv4 Internet has been facing the infamous IP address depletion barrier. In practice, typical IPv4 Internet edge networks can be expanded by incorporating private addresses and NAT devices. In this paper, major limitations of NAT-expanded private networks are presented. Furthermore, a solution is proposed to encourage the mixed usage of private and public IP addresses in a single edge network domain. The solution comprises of two key ideas : super-subnet mask and shared NAT. Super-subnet mask removes the routing boundary between private and public hosts. Shared NAT saves public IP address resources by sharing them among several private networks. These ideas not only encourage the coexistence of heterogeneous address classes, but also lead to efficient sharing of global IP addresses.