Ipv6 Address Space Allocation Schemes - Issues and Challenges, A Survey

Research and discussion on the Internets addressing and routing scalability problems has been for more than a decade. IP aware growing population, and learned needs in terms of site multi-homing, traffic engineering, non-aggregatable address allocations and policy based routing have resulted in the continuous alarming growth of the routing tables in the Default Free Zone (DFZ). Constraints posed by the existing router technology, address allocation and architectural history have made identifying and deploying an effective solution difficult. These sources that influence the core routing table growth can lead to fragmentation or de-aggregation of address prefixes. Much of the growths of the routing tables in the DFZ are a result of de-aggregation of address prefixes. Aggressive topological aggregation is the solution to scale the routing system, that is, IP address allocations should follow topology. IP address allocation and management and the scalability of the routing system are interrelated and only certain IP address allocation and management policies yield scalable routing. The Regional Internet Registries (RIRs) individually use various allocation techniques within their respective regional pools of address space. Proper choice of address allocation algorithm would help in reducing fragmentation, thus reducing routing table size and hence increase Internet addressing and routing scalability. This paper analyzes the various address allocation algorithms used by the RIR´s and based on the lessons learnt proposes a hybrid address allocation scheme for IPv6 that would achieve appreciable address aggregation compared to the existing IPv6 address allocation algorithms, and effectively reduce routing table size in the DFZ. This would help in increasing the Internet addressing and routing scalability and thus enhance the performance of the Internet.