Optimization of Critical Data Synchronization via Link Overlay RNG in Mobile Ad Hoc Networks

Overview & Synopsis

In practice, ad hoc networks are still too unreliable for standard mobile and vehicular communications. It is thus important to complement current protocols in this context, with schemes guaranteeing the exchange of critical data when needed. A promising approach in this realm is to use an overlay subgraph, over which critical messages are exchanged and acknowledged in a peer to peer fashion. Overlay nodes' local databases remain thus synchronized over time, at least concerning critical data. This paper elaborates on the problem of performance, related to the discovery and maintenance of such overlay networks in a mobile ad hoc context. We analyze SLOT, an overlay selected based on a Relative Neighbour Graph (RNG) scheme. We then apply SLOT to a standard IP protocol: OSPF, a traditional routing protocol which has recently been extended, with RFC 5449, to work also on mobile ad hoc networks, and which makes use of a similar overlay synchronization subgraph. This paper compares the performance of RFC 5449 with that of SLOT-OSPF, our proposed OSPF extension for mobile ad hoc networks using SLOT. Simulations of various mobile ad hoc network scenarii show that SLOT-OSPF produces drastically less control traffic than RFC5449, allowing SLOT-OSPF to function correctly while RFC5449 stalls, when the number of routers in the domain is large.