Meter-CAD-DCC communications architecture?
Background: my supplier, Bulb, is no longer recording readings from our smart meters even though my Glowmarkt CAD works fine and I can read the meters just fine with the Bright app, whether or not at home. Active discussions with Bulb are ongoing.
In aid of those discussions, I'd like to understand more about the communications architecture of SMETS2 metering in conjunction with Glowmarkt's CAD. I know this much:
• The CAD is joined to the HAN and also to Glowmarkt via WiFi.
• Glowmarkt is a DCC "Other User", and can get current and historic data directly from the DCC.
• The Bright app on my phone can communicate only by Internet (WiFi or cellular) to Glowmarkt's cloud services.
• (MQTT relies on cloud services in some cases, and may be available locally in others.)
Given these, does Glowmarkt rely on the CAD for collecting data at all, or does Glowmarkt use only its DCC connection to get data?
The significance of this question is that if I can read my meters both with my CAD and Bright on my phone, whether or not I am home and Glowmarkt relies exclusively on the DCC for receiving data, then that proves my meters are fine, and the DCC is receiving, recording and relaying data just fine, too.
This in turn would prove that the problem exists between the DCC and Bulb.
Given the mess that Bulb is in, I wouldn't be surprised if they are, in fact, receiving data from the DCC but, for whatever reason, the data are not being associated with my account, therefore Bulb think they are not receiving data.
Their solution is to request a reboot of the meters and IHD via the DCC. They've tried this once and say they've requested a second reboot but, if somehow the link between Bulb and the DCC is broken (at least in relation to our account), that request is unlikely to get through. It stands to reason that if they cannot push tariff updates, pushing requests to reboot anything are not likely to work either.
(As an aside, it'd be interesting to know how customers and meters are related. The DCC and DNOs know how MPANs and MPRNs relate to specific dwellings by postal address. Suppliers associate a billing account (liable person) with an address and MPAN. How do suppliers relate smart data, via MPANs and MPRNs only? Or is there some other sort of ID involved?
That question is pretty deep in the weeds and may be answerable only by someone with detailed knowledge of the SMETS2 protocol, but it's worth asking all the same. I've skimmed through what's published in the technical specs and I see there are separate meter IDs independent of the MPAN and plus there are similar E2E cryptographic and anti-tamper provisions as are found in PCI DSS compliant payment card terminals and readers.
So long as the DCC don't lose the association between ESME and MPAN, then none of that detail matters. Again, knowing whether the Glowmarkt CAD relies wholly on the DCC for data collection would give a fair clue as to whether such association is still intact.