This is a RFC to initiate discussion regarding the addition of a modem technology type indicator property to the modem DBus interface. The need for such a property has arisen as we cannot use the current interface to guarantee understanding of a modem device's technology type to the upper layers at all times.
The current design supports the behaviour where the upper layers can search for whichever technology interfaces are available and instantiated by the current modem device and execute accordingly. However, such behaviour only applies in the case where there are distinguishing atoms (and associated DBus interfaces) representing fundamentally different behaviour for different modem types. We need to support the scenario where, for example, the different modem types share the same DBus interface due to some, e.g. abstraction, in property meaning, but the upper layers need to behave differently depending on the technology. Currently, any technology distinguishing atoms are optional, which means we cannot rely on these to provide interfaces to be used by the upper layers to establish the technology type, e.g. ofono.cdma.voicecall may not always be available even if the underlying modem is a CDMA modem. This implies we would need to assign the responsibility of broadcasting the modem device technology type through the core modem interface. An example use case: In 3GPP, the serial number of a device is referred to as the International Mobile Equipment Identity (IMEI). In 3GPP2, the serial number of a device is referred to as the Mobile Equipment Identifier (MEID). In oFono, such a feature is abstracted to the same serial number concept so GSM and CDMA modems can both broadcast through the "Serial" modem interface. However, the upper layer may need to process this value differently depending on the current technology for e.g. display purposes. This interface is provided through the core modem code, but we have no way of communicating the current modem device type if operating in an initial offline mode without any other atoms instantiated. We envisage the potential for more such use cases in the future and look forward to comments/discussion regarding our options. Thank you Dara Spieker-Doyle (1): doc: Add modem technology type property doc/modem-api.txt | 11 +++++++++++ 1 files changed, 11 insertions(+), 0 deletions(-) _______________________________________________ ofono mailing list ofono@ofono.org http://lists.ofono.org/listinfo/ofono
