02-3 COSEM - a new Internet Application
The base: the standardized COSEM framework for meter data exchange
With International standardisation in the IEC and conformance testing achieved, the next focus of the DLMS User Association is moving COSEM to the information highway, the Internet.
The COSEM framework allows transporting the COSEM meter model described with the COSEM interface objects, through the communication media independent COSEM Application layer and the media dependent lower protocol layers.
The COSEM Internet profile
IEC 62056-46 and 6-42 define how to transport COSEM over a direct link, over PSTN or over GSM, using the data link layer based on the widely used HDLC standard. Further information is available in <http://www.iec.ch/online_news/etech/prodserv.htm>.
A feasibility study prepared recently has proven that the original objective – to be able to transport the COSEM meter model over a variety of communication media, including the Internet – can be achieved.
It is relatively straightforward to use the TCP-UDP/IP layers residing over lower data link and physical layers instead of the data link layer and physical layers currently defined in IEC 62056-46 and 6-42. The addressing provided by the HDLC layer can be mapped to IP addresses for the physical devices and TCP-UDP port numbers for the logical devices and application associations. The existing Application layer protocol data units, carrying the DLMS/COSEM services can then be easily transported as TCP or UDP datagrams. In this way, the COSEM applications can easily live together with other internet applications.
For lower layers, several options, like dial in services, GPRS and Ethernet have been considered.
Security items (including firewalls) and implementation related questions (e.g. resource requirements) are next on the agenda. Conformance testing will be included, too!