Avoid LAN Switches IP Routers provide a better alternative for a Real-Time Communication System

This paper describes how routers can be used for factory communications. This statement is based on QoS management features of the IP protocol, especially schedulers, shapers, markers, filters that can be used and the ability of IP datagrams to carry priority in the ToS field for Ipv4 or the DS field for Ipv6. This last property allows priority inheritance of real-time threads across a factory network. As a conclusion, switches could be used for devices connection, whilst routers could be dedicated to real-time priorities management. We describes in this paper our experiments on the use of iproute2 and tc in Linux to improve our knowledge of QoS management in routers.