Please consolidate nRF9160 documentation about CP-RAI and AS-RAI

[Achim Kraus]

Knowing, that the AS-RAI implementation is experimental, I would still prefer to have more documentation about the details.

I already asked for these details in an other issue (see Details of AS-RAI and CP-RAI fallback ) but for me there are still some gaps.

The above referred thread discussed, that requesting to use Rel. 14 AS-RAI, the modem falls back to Rel. 13 CP_RAI, if AS-RAI isn't supported by the network provider. So far, so good. The nasty point seems to be, that you can't use this fallback without knowing that, because the supported options seems to differ for AS-RAI and CP-RAI and a function to see, that the modem decided to fall back, is missing.

My results (the trace are provided in the referred thread):

With Rel. 14 AS-RAI only the SO_RAI_NO_DATA seems to work, with SO_RAI_ONE_RESP I had no success.

With requesting Rel. 14 AS-RAI, but fallback to Rel. 13 CP-RAI, SO_RAI_NO_DATA doesn't work, but SO_RAI_ONE_RESP is now working.

My questions:

1. Please document, which options are working in which mode (SO_RAI_NO_DATA, SO_RAI_LAST, SO_RAI_ONE_RESP combined with Rel. 14 AS-RAI, AS-RAI fallback to CP-RAI).

2. Is it possible the check, if the modem falls back to Rel. 13 CP-RAI? Especially, if the first question shows, that there are no common supported options, such a function helps to implement a working application.

Thanks in advance. 

[Achim Kraus]

Michal Mühlpachr said:

What about SO_RAI_NO_DATA in this case?

Isn't it your experience, that this doesn't work?

It also doesn't work in my tests.

[Michal Mühlpachr]

Achim Kraus said:

Isn't it your experience, that this doesn't work?

Yes, it is, I'm just making sure I understand this correctly.

[Michal Mühlpachr]

Achim Kraus said:

This is mixed up and the sayings are moving ("fallback" is now "implicitly used").

if I understand, the description is consistent with the previous ticket. AS-RAI and CP-RAI are used simultaneously if the operator supports them (priority undefined by standards, EPC implementation dependent, but usually AS-RAI has precedence). When AS-RAI is enabled on the modem but the operator does not support it, the modem attempts to use CP-RAI.

BTW is there API way to detect whether network is R13 or R14, weather AS-RAI or R14 features are supported?

[dejans]

Hi,

Michal Mühlpachr said:

is there API way to detect whether network is R13 or R14, weather AS-RAI or R14 features are supported?

Our customers do not need to know which RAI is supported or which is enabled (if any). It is enough to configure last_packet/one_resp/no_data socket option based on the situation in application and modem will use it in the best possible way depending on network's RAI support. Simply set the socket options to the best of application knowledge. There is no need for knowing other possible sockets in use when setting socket options for one socket because modem has common understanding of all sockets. In addition, it is not necessary to know which protocol (TCP or UDP) is used because the protocols are handled below the socket interface.

Best regards,
Dejan

[Achim Kraus]

> It is enough to configure last_packet/one_resp/no_data socket option

That is exactly not the case! Someone need to know, that using one_resp or no_data doesn't work reliable, these options must be used together.