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Bug #5849

closed

emergency call: Support MobileIdentity=IMEI when no IMSI is used in the phone

Added by pespin about 1 year ago. Updated about 1 year ago.

Status:
Resolved
Priority:
Normal
Assignee:
-
Category:
-
Target version:
-
Start date:
01/02/2023
Due date:
% Done:

100%

Spec Reference:
3GPP TS 24.008

Description

See 3GPP TS 24.008 section 10.5.1.4 "Mobile Identity":

"For emergency call establishment and re-establishment the mobile station shall select the mobile identity type with the
following priority" [...]
-IMEI: he IMEI shall be used in cases where no SIM/USIM is available or the SIM/USIM is considered as
not valid by the mobile station or no IMSI or TMSI is available." 

However, right now, bsc_compl_l3() calls osmo_mobile_identity_decode_from_l3() and bsc_subscr_find_or_create_by_mi() but the later doesn't support parsing GSM_MI_TYPE_IMEI or GSM_MI_TYPE_IMEISV.

As of now, we carry on with conn if no subscr is created, but ideally that should change in the future and reject the conn (see bsc_compl_l3() comments in code).

Ideally we should create a TTCN3 test in BSC_Tests to validate everything works fine before/after implementing that case.


Related issues

Related to OsmoMSC - Feature #6000: Allow emergency calls without IMSI (using IMEI as MI)New04/12/2023

Actions
Actions #1

Updated by pespin about 1 year ago

bsc_compl_l3() is also passing "mi" to function bsc_find_msc(), we may need to update that function too to handle GSM_MI_TYPE_IMEI

Actions #2

Updated by neels about 1 year ago

On Mon, Jan 02, 2023 at 04:09:39PM +0000, pespin wrote:

bsc_compl_l3() is also passing "mi" to function bsc_find_msc(), we may need to update that function too to handle GSM_MI_TYPE_IMEI

That is not necessary -- bsc_find_msc() uses a TMSI mi if present to extract the NRI indicating a previously selected MSC. For all other mi types (when there is no NRI), it uses the next MSC by round robin.

Actions #3

Updated by pespin about 1 year ago

https://gerrit.osmocom.org/c/osmo-bsc/+/30843 bsc_subscriber: Allow creating subscribers identified by IMEI
https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/30841 bsc: Introduce test TC_assignment_emerg_setup_allow_imei

Actions #4

Updated by pespin about 1 year ago

  • Status changed from New to Feedback
  • % Done changed from 0 to 90

The related code should be implemented and tested with the patches previously submitted plus this one:
https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/30847 bsc: TC_assignment_emerg_setup_allow(_imei): Test full voice establishment

Actions #5

Updated by pespin about 1 year ago

  • Status changed from Feedback to Resolved
  • % Done changed from 90 to 100

Patches merged, closing.

Actions #6

Updated by pespin 11 months ago

  • Related to Feature #6000: Allow emergency calls without IMSI (using IMEI as MI) added
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