An evaluation of layer 2 and layer 3 routing on high capacity aerial directional links

The increasing need to augment ground/surface networks with an aerial tier has prompted research in understanding whether mobile ad-hoc network (MANET) routing techniques can be applied to the unique characteristics of high capacity airborne links. Due to the high cost of development and fielding such systems, the U.S. Department of Defense (DoD) is seeking joint-service solutions that take in requirements from the Navy, Air Force, Army, and Marines. One of the challenges of the joint architecture is the differing routing architectures. The Navy prefers operating the provider network as layer 2 for simplicity, while the Air Force and Army requires layer 3 because many radio systems do not converge on Ethernet frames. In this paper, we examine the tradeoffs between layer 2 and layer 3 network on the high capacity airborne backbone and implement a software-based router that can support either approach. We evaluate both approaches with representative traffic and topologies to quantify performance in terms of convergence time, overhead and efficiency for each approach.