Source-Destination Routing for Optimised Link State Routing Protocol

Typical routing protocols maintain, in their RIB (Routing Information Base) entries permitting destination-based forwarding: for a given data packet, the choice of next hop is a function of the destination address only. However, in deployments where a given network is multi-homed, and where ingress filtering is commonly applied, a routing protocol is required to be able to provide routes so as to forward a data packet (i) to the destination address of the data packet, while (ii) routing through the gateway for which the source address of the data packet is topologically correct. This is called source-destination routing. This paper presents an extension to the Optimized Link State Routing Protocol version 2 (OLSRv2), providing support for such source-destination routing. In a multi- homed network, this OLSRv2 extension provides routes for data packets based also on the source prefix announced by the gateways. The extension is interoperable with unextended OLSRv2. The performance of this extension is quantified by way of simulation studies.