From ISP Address Announcement Patterns to Routing Scalability

The Internet routing table size has been growing rapidly. In future Internet, if given a much larger public address space (e.g., IPv6), the potential expansion can be very significant, and the cost of a large routing table will affect many ISPs. Before devising methods to ensure routing scalability, it is necessary to understand what factors lead to the expansion of routing tables and to what extent they impact. In addition to the well known factors such as multi-homing, traffic engineering and non-contiguous address allocations, the tendency towards convenient address management also increases the routing table size. In this paper, we take a measurement-based approach to examine quantitatively how various factors, especially the current address aggregation status of different types of ISPs, contribute to the growth of global routing table. We show how these patterns affect the routing scalability, and discuss the implications as we plan address management and routing for the future Internet.