A major, and long discussed, demerit of the current Internet architecture is the insufficient IPv4 address space, IPv4 being one of the fundamental protocols used in the Internet. As more and more devices become Internet-capable, the feasibility of static IPv4 addressing (i.e., assigning each node a unique IP address even though that particular node might not always be online) is reduced. CIDR allows more effective address allocation, DHCP the dynamic reallocation of the addresses, and NAT enables address hiding and private networks. On the other hand, these techniques reduce the availability of the hosts in the Internet. The fundamental point of IPv4 connectivity is that one can identify a node by its IP address. However, if the address changes dynamically or is hidden, this connectivity model is broken. In this thesis, several existing solutions to the issue are discussed: IPNL, IPv4+4, HIP and NUTSS, among others. In particular, we concentrate on one solution, Realm Aware Source Routing (RASR). A Proof-of-concept implementation of RASR is introduced and its feasibility analyzed and compared with other solutions. We will show that RASR has potential, though also some limitations. In other words, it is not yet a complete solution. Further research on the topic is encouraged.