A Local Metrological Network (LMN) is a local metrological network that forms the interface to smart meters
. The smart metering systems receive their consumption data for energy, electricity, water or gas from sensors
, whichtransmit it at regular intervals to the smart meters, which process it and forward it to the central communication unit SMGW gateway
. Data transmission from the sensors to the smart meters and the SMGW gateway takes place via the M-Bus or the wireless M-Bus. In the wired version, the transmission is encrypted at the transport layer and the session layer by Transport Layer Security (TLS) with 128 bits. This secures all data streams in terms of integrity, authenticity and confidentiality. On the application layer of the SMGW, the required information is collected via OBIS indices. The corresponding information is mapped in the rule set for the data exchange of smart meters Companion Specification for Energy Metering (COSEM). In the underlying representation layer, the COSEM classes are packaged in an SML file, Smart Meter Language (SML).