His main research topics are IPv6, high-speed networking and network metrology. His main focus in the IPv6 area is on the transition mechanism. He is co-author of the IPv4/IPv6 transition mechanisms. Laurent Toutain works on network auto-configuration with IPv6, especially for home networking environments. He has participated to the study of the impact of IPv6 in the ROHC (Robust Header Compression) protocol, which will be used in 3G networks to compress IPv6 headers.

His main research interests concern distributed wireless networks such as ad hoc, vehicular and sensor networks. He works on the medium access, examining the compromises between different network objectives and deriving distributed algorithms to approximate the desired goal. He also works on the conception of lightweight routing protocols dedicated to specific network topologies and mobility patterns and on the distributed identification of such network characteristics with and without the aid of a localization service.