An implementation of a Common Virtual Multipoint Interface in Linux

In highly dynamic airborne environments, per link information becomes crucial in effectively routing packets throughout the network. Point-to-point Protocol over Ethernet (PPPoE) RFC4938/5578¹ describes an elegant way to standardize an interface to transmit per link information to the router to make educated routing decisions. These dynamically changing point-to-point links to the router pose an interesting challenge in defining interfaces in the router configuration and providing multicast/broadcast emulation. In this paper, we present an open-source, Linux implementation of a Common Virtual Multipoint Interface (CVMI). The CVMI aggregates multiple point-to-point interfaces into a virtual interface and provides multicast/broadcast emulation on these dynamically changing interfaces. We describe our implementation in detail and show how each link can be grouped to perform differently despite the homogeneous nature of PPP links and provide some basic performance evaluations to show functionality.