Internet Multi-Homing Problems: Explanations from Economics

Companies seeking to ensure that their Internet connection is resilient often purchase services from multiple providers. This leads them inexorably towards having their IP address range visible in the global routing table, increasing the resource usage of every Internet router. Since this is essentially ‘free’, yet impacts the cost and stability of every router in the world, this is a classic ‘tragedy of the commons’. There is little prospect of change in the IPv4 world, but there is a chance to fix the problem as IPv6 is rolled out. Unfortunately, SHIM6, the engineering solution chosen to solve this issue in IPv6, will only be effective if universally adopted, and there are no short-term incentives to prefer SHIM6 over a duplication of the IPv4 arrangements. Incentives could be artificially introduced by requiring payment for adding multihomed address space to the global routing table – a näıve estimate of the actual cost being 77 000 per routing prefix. However, it would be almost impossible to ensure the substantial revenues involved are correctly redistributed to those bearing the costs.