The access point duplicates the sender's telegram or frame and stores a copy on each of the connected networks. The LAN can adopt different topologies, such as star, ring, or tree. On the receiving side, the second access point transmits the first incoming telegram to the receiver. The second incoming telegram, from the other LAN, is discarded. The use of two separate networks and the PRP protocol ensures secure and timely transmission. Unlike other redundancy procedures that use a single physical network, this method does not require reconfiguration time. High-availability redundancy connections are essential in the energy sector and in process automation, for example, in the pharmaceutical or chemical industries.
The new Siemens access points are available in two versions: the Scalance X204RNA in a plastic enclosure with four RJ45 power ports, and the Scalance X204RNA EEC (Enhanced Environmental Conditions) in a metal enclosure with two power ports and two combined power-optical ports for SFP (Small Form-Factor Pluggable) transceivers and a wide-range power supply. The SNMP (Simple Network Management Protocol) provides access to the information needed for network diagnostics.
