Routing inference based on pseudo traffic matrix estimation

Abstract

Routing information is so crucial to an operational network that it is always regarded as confidential by network administrators. This paper proposes a novel routing inference method that only needs the knowledge of the network topology and the link counts, both of which can be obtained from MRTG (multi-router traffic grahper) data. The insight is that the traffic observed on each link arises from the superposition of the traffic demands between the origin-destination (OD) pairs and each traffic demand corresponds to a unique path. The method employs expectation maximization (EM) algorithm cooperating with a hypothetic pseudo routing scheme, which is expected to embrace the real routing, to compute a pseudo traffic matrix. The real routing then can be conjectured from this pseudo traffic matrix. This method is applied to a real IP network, and the results show that it correctly infers the routings for 87% OD pairs.