ABSTRACT
The Train Communication Network (TCN) represents a fieldbus, which is used in railway vehicles. This established fieldbus has been standardized as an IEC standard by an international alliance of railway manufacturers. Ethernet protocols are structured in a layered and modular way. The function of an Ethernet switch is based on the Ethernet message format. Ethernet switches support Layer 3 protocols such as OSPFv2, RIPv2, Virtual Router Redundancy Protocol (VRRP), IGMP snooping, IPv4 forwarding, DiffServ, ARP, ICMP, as well as DCHP client/server to receive or distribute IP addresses. A ring topology achieves such protection in a very simple and cost-effective way. It provides fault protection for single failures. Most requirements in TCN can be met with methods, which are specific to embedded Ethernet applications but not necessarily specific for TCN. Thus, an Ethernet-based TCN may benefit from mainstream embedded Ethernet applications such as in industrial automation, energy provision, and avionics.
