To Forward or not to Forward: Considerations on and Experiments with Network Layer Forwarding in Combination with Middleware Services for Group Communications

Group communications is central to information dissemination in tactical edge environments as an approach to delivering information to multiple nodes in a bandwidth efficient manner. The NATO IST-161 Research Task Group on Efficient Group and Information Centric Communications in Mobile Military Heterogeneous Networks has been exploring and evaluating multiple approaches, including specific middleware capabilities that provide group communications. Some of these middleware implementations incorporate their own capabilities for information routing / forwarding, which raises the question of layering them on top of existing IP multicast forwarding mechanisms. This paper examines the benefits and tradeoffs of using an underlying network forwarding approach, Simplified Multicast Forwarding (SMF) aided by the OLSRv2 unicast routing protocol, in combination with group communications middleware. The experiments are carried out in the context of disseminating Blue Force Data in the Anglova scenario with and without the assistance of SMF and OLSRv2. The current results show that further integration is necessary between the middleware protocols and the underlying routing protocols in order to achieve the desired performance.