On Compact Routing for the Internet

TL;DR

This paper demonstrates that logarithmic scaling of routing tables on Internet-like topologies is fundamentally impossible due to topology dynamics and addressing schemes, challenging existing compact routing assumptions.

Contribution

The paper provides analytic and simulation evidence that current compact routing models cannot scale logarithmically on dynamic, topology-independent addressing Internet-like networks.

Findings

Routing control messages per topology change cannot scale better than linearly.

Logarithmic routing table size scaling is broken by topology-independent addressing.

Fundamental assumptions behind current routing models need re-examination.

Abstract

While there exist compact routing schemes designed for grids, trees, and Internet-like topologies that offer routing tables of sizes that scale logarithmically with the network size, we demonstrate in this paper that in view of recent results in compact routing research, such logarithmic scaling on Internet-like topologies is fundamentally impossible in the presence of topology dynamics or topology-independent (flat) addressing. We use analytic arguments to show that the number of routing control messages per topology change cannot scale better than linearly on Internet-like topologies. We also employ simulations to confirm that logarithmic routing table size scaling gets broken by topology-independent addressing, a cornerstone of popular locator-identifier split proposals aiming at improving routing scaling in the presence of network topology dynamics or host mobility. These pessimistic findings lead us to the conclusion that a fundamental re-examination of assumptions behind routing models and abstractions is needed in order to find a routing architecture that would be able to scale ``indefinitely.''