On the IP Traffic Matrix Problem in Hybrid SDN/OSPF Networks

TL;DR

This paper investigates the challenges of obtaining complete IP traffic matrices in hybrid SDN/OSPF networks and proposes a placement algorithm and hybrid measurement approach to address these issues.

Contribution

It introduces a placement algorithm and hybrid measurement method to improve traffic matrix estimation in hybrid SDN/OSPF networks.

Findings

Hybrid SDN/OSPF networks face challenges in traffic matrix estimation due to limited SDN counters.

Augmenting SDN statistics with SNMP measurements on backup links improves accuracy.

A placement algorithm guarantees a complete IP traffic matrix in the network.

Abstract

IP networks with a hybrid control plane deploy a distributed routing protocol like OSPF and the centralized paradigm of SDN in parallel. The advantages and disadvantages of a hybrid control plane have already been extensively discussed in the literature. This paper examines to what extent hybrid SDN/OSPF can solve the IP traffic matrix and related monitoring problems, inherent to the IP layer. The problem persists in hybrid networks, as the required SDN byte counters for a complete traffic matrix may not be sufficiently implemented (or even not at all), or the deployed SDN nodes may be too few, or not adequately located in the network. For such cases, we propose to augment the SDN traffic statistics with SNMP-based measurements on IP backup links. We address implementation and network function virtualization aspects of the required hybrid monitoring infrastructure and discuss the timing issues of the measurements based on hands-on experiences in our lab. We furthermore provide a placement algorithm for SDN nodes and backup links that can guarantee a complete IP traffic matrix.