L3Geocast: Enabling P4-Based Customizable Network-Layer Geocast at the Network Edge

Geocast is a one-to-many communication paradigm that enables the transmission of data packets to a designated area rather than an IP address. The most common geocast solutions rely on the application-layer Geolocation-to-IP database. But these IP-based approaches cannot cope with the challenges of flexibility and mobility in a granularity-customizable geocast scenario. While some non-IP network-layer (L3) attempts have resulted in low addressing accuracy and poor routing scalability. Besides, the clean-slate design is incompatible with the existing network. To address these issues, this article proposes an innovative network-layer geographic addressing scheme that leverages P4-based Software Defined Networks (SDN) to enable flexible geocast with high accuracy. Based on the aggregation relationship of the geographic area, a network-layer routing strategy is designed to enhance routing scalability. Compatibility is improved by deploying the network-layer designs only at the network edge where granularity-customizable geocast is implemented, without requiring changes to the current IP infrastructure. Then, the network-layer functions are integrated with an application-layer mapping service to support intercommunication between different network edges. Furthermore, a prototype system is built to implement and evaluate the proposed L3Geocast, which outperforms the existing approaches in terms of communication latency and mapping overhead.