OLSRv2 for Community Networks: Using Directional Airtime Metric with external radios

Abstract

In this paper we present novel approaches to routing in Community Networks. We combine recent advances in OLSR development regarding modularization, scalability, extensibility, and metrics with a node architecture concept based on radio and router separation adopted to Community Networks. This node architecture consists of a single router with several external radios acting as wireless bridges and connecting to the router via standard Ethernet, which we refer to as Hybrid Node Design. Furthermore, we propose the use of our Directional Airtime (DAT) routing metric that is suitable for the heterogeneous link characteristics often found in Community Networks. By using this metric we achieve a more stable route selection process and improved throughput in comparison to the OLSR-based approach currently used in Community Networks. In addition, we present some enhanced features unique to our implementation that include means to increase the self-configuration capabilities in IPv4, IPv6, and dual-stack configurations. As a consequence, we recommend that it is the right time for Community Networks to start the migration process from OLSRv1 to OLSRv2.For the implementation process and the protocol evaluation we followed a testbed-driven approach. It was supported by the Confine testbed both, in a virtualized version, as well as in a physical deployment in a dense setup at Fraunhofer FKIE. The physical testbed consists of over 20 indoor research nodes on two floors implementing our hybrid node design. Link layer information from the radio devices to the router is provided by the DLEP protocol, which was designed especially for wireless mesh networks. The obtained link layer information is used by OLSRv2 for routing metric computation. We propose the use of this architecture in Community Networks in order to increase scalability and simplify network administration.