Design and implementation of variable-length locator allocation protocol for scalable Internet addressing

Hierarchical address allocation and hierarchical routing design has long been suggested to reduce the forwarding information base (FIB) size in the Internet core. However, the hierarchical design is not put into practice. We implemented the hierarchical and automatic number allocation (HANA) protocol for allocation of IPv4 and IPv6 address spaces to autonomous systems (ASes) and the FIB size reduction. The HANA protocol allocates multiple address spaces to an AS from the upper ASes. Multihoming using multiple addresses provides an AS with multiple paths. That is, detour paths are inevitably prepared in advance, even when a network failure does not occur. In this paper, we provide the highest flexibility to HANA-based networking, namely, supporting variable-length addressing scheme. The variable-length addressing schemes suppress renumbering caused by the address space extension that occurs in the fixed-bit-length addressing schemes. In addition, we propose a new function of exchanging allocated numbers, and implement it in the current HANA system. The flexible HANA system provides locator allocation with low renumbering costs and realizes scalable addressing in future internetworking.