Feature #1597

External interface for USSD

Added by laforge over 2 years ago. Updated 11 days ago.

Target version:
Start date:
Due date:
% Done:


Estimated time:


we already have SMPP for SMS, but don't have similar functionality for USSD, i.e. a way in which external applications can exchange USSD with MSs.

There are some provisions for USSD in SMPP, but I think they don't really appreciate the session-oriented nature of USSD.

In either case, I'm not aware of any standard to hand USSD to external applications. Of course there's MAP, but nobody wants to implement that in an external application...

ussd_ms_init.png View ussd_ms_init.png 29.4 KB MS initiated USSD-session fixeria, 04/08/2018 04:45 PM
ussd_net_init.png View ussd_net_init.png 36.2 KB Network initiated USSD-session fixeria, 04/08/2018 04:45 PM
ussd.xml ussd.xml 2.82 KB Sources for fixeria, 04/08/2018 04:50 PM

Related issues

Related to OsmoMSC - Feature #2931: USSD test cases in TTCN-3Stalled2018-02-11

Related to OsmoHLR - Feature #3433: External interface for USSDClosed2018-07-29


#1 Updated by laforge 12 months ago

  • Assignee set to fixeria

#2 Updated by laforge 8 months ago

  • Project changed from OsmoNITB to OsmoMSC

#3 Updated by fixeria 5 months ago

  • Status changed from New to In Progress
  • % Done changed from 0 to 20

First of all, we need to extend GSUP with USSD support.

#4 Updated by fixeria 4 months ago

Found a few great pictures about MAP message flow.

User-initiated session example

Network-initiated session example

#5 Updated by fixeria 4 months ago

  • Tracker changed from Bug to Feature
  • % Done changed from 20 to 50

#6 Updated by fixeria 4 months ago

If anyone has and/or can record LAPDm traces of USSD sessions with a commercial
network or even MAP traces, I would be more than happy.

There is a sample capture:

but one is too trivial...

#7 Updated by fixeria 4 months ago

Oh, WOW! I've just found a MAP trace with lots of USSD sessions.

This is exactly from where I took the pictures above.

#8 Updated by laforge 4 months ago

#9 Updated by fixeria 4 months ago


I've visualized some possible USSD-session examples...

The images are created using, and can be opened
and edited (source XML attached) there.

#10 Updated by fixeria about 2 months ago

  • Status changed from In Progress to Feedback
  • % Done changed from 50 to 90

The new changes which implement support of both MS-initiated and network-initiated
SS/USSD transactions have been send to review:

The only missing part at the moment is notification about errors,
e.g. when Paging of a subscriber is failed, or when a message decoding is failed.

#11 Updated by fixeria about 2 months ago

  • % Done changed from 90 to 80

What would be also great to implement:

  • processing / forwarding of the Cause IE in GSM 04.80 RELEASE COMPLETE message
  • processing of SS Version IE in MO GSM 04.80 REGISTER message

#12 Updated by laforge 16 days ago

  • Tags set to USSD

#13 Updated by laforge 16 days ago

#14 Updated by fixeria 11 days ago

  • Status changed from Feedback to Stalled

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