Q.1 Default routing mechanism

31.1113GPPRelease 18TSUniversal Subscriber Identity Module (USIM) Application Toolkit (USAT)

In addition to the mechanism defined in ETSI TS 102 223 [32], the MT shall route USAT commands as follows:

– SET UP EVENT LIST shall be routed to all entities supporting the command, each containing only the events supported by the entity, even if the list is empty (which allows for proper deregistration of events set up earlier). For the TERMINAL RESPONSE to the UICC, the responses from the MT and the TE have to be combined as follows:

– The MT shall check if it is able to set up the events it supports itself. If the MT is currently unable to process command or if the set up of the events would fail, the MT shall send this result in the TERMINAL RESPONSE without forwarding the command to the TE.

– If the MT is capable of setting up the MT events, the list of TE events shall be forwarded to the TE and the TE shall send its TERMINAL RESPONSE.

– If the TE command was successful, the MT shall set up its events and report that the command was performed in the TERMINAL RESPONSE. If the MT or the TE or both have performed the command with partial comprehension or with missing information, this shall be reflected in the TERMINAL RESPONSE; if one reported partial comprehension and the other missing information, the MT response takes precedence.

– If the TE reports that it is currently unable to process command or the command failed, the MT shall report this in the TERMINAL RESPONSE.

– REFRESH shall be routed to all entities supporting the command to inform them about modified Efs; only the MT shall perform other activities indicated in the command (e.g. UICC reset). For the TERMINAL RESPONSE to the UICC, the responses from the MT and the TE have to be combined as follows:

– The MT shall check if it is able to perform the REFRESH. If the MT is currently unable to process the command or the command would fail, the MT shall send this result in the TERMINAL RESPONSE without forwarding the command to the TE.

– If the MT is capable of performing the REFRESH, the command shall be forwarded to the TE and the TE shall send its TERMINAL RESPONSE, but if there is a refresh action to be performed by the MT (e.g. USIM initialisation), the MT shall send its response to the TE’s TERMINAL RESPONSE only after the refresh action has started to avoid that the TE tries to access the UICC before the refresh action.

– If the TE command was successful, the MT shall perform the REFRESH and report that the command was performed in the TERMINAL RESPONSE. If the MT or the TE have performed the command with a limitation (partial comprehension, missing information, additional Efs read, requested icon could not be displayed or USIM/ISIM was not active) this shall be reflected in the TERMINAL RESPONSE; if both reported different limitations, the MT response takes precedence.

– If the TE reports that it is currently unable to process command or the command failed, the MT shall report this in the TERMINAL RESPONSE.

– OPEN CHANNEL shall be routed according to the indicated bearer type. To avoid conflicts in channel identifier assignment, the MT shall replace the destination device identity by an available channel identifier and the entity providing the bearer type shall use this channel identifier in its response.

– Subsequent BIP commands shall be routed according to the channel identifier.