The k-Interval Routing Scheme (k-IRS) is a compact routing scheme on general networks. It has been studied extensively and recently been implemented on the latest generation of the INMOS transputer router chips. In this paper we investigate the time complexity of devising a minimal space k-IRS and we prove that the problem of deciding whether there exists a 2-IRS for any network G is NP-complete. This is the first hardness result for k-IRS where k is constant and the graph underlying the network is unweighted. Moreover, the NP-completeness holds also for linear and strict 2-IRS.
Ordered interval routing schemes
