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Feature #1597

External interface for USSD

Added by laforge about 5 years ago. Updated over 2 years ago.

Status:
Stalled
Priority:
Low
Assignee:
Category:
-
Target version:
-
Start date:
02/23/2016
Due date:
% Done:

80%

Resolution:
Spec Reference:
Tags:

Description

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 draw.io fixeria, 04/08/2018 04:50 PM
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Checklist

  • 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

Related issues

Related to OsmoMSC - Feature #2931: USSD test cases in TTCN-3Resolved02/11/2018

Related to OsmoHLR - Feature #3433: External interface for USSDClosed07/29/2018

Associated revisions

Revision 72696040 (diff)
Added by Vadim Yanitskiy almost 3 years ago

GSUP: implement TCAP-like session management

Unlike TCAP/MAP, GSUP is just a transport layer without the
dialogue/context. This prevents us from having session based
communication, required e.g. for USSD. But we can emulate
TCAP dialogue by adding additional IEs, which would allow
to relate each message to a particular session.

This change introduces the following IEs:

- OSMO_GSUP_SESSION_ID_IE,
- OSMO_GSUP_SESSION_STATE_IE,

which optionally can be used to indicate that the message is
related to a session with given ID, and to manage session
state, i.e. initiate, continue, and finish.

Change-Id: I1cee271fed0284a134ffed103c0d4bebbcfde2a8
Related: OS#1597

Revision 36c7b33c (diff)
Added by Vadim Yanitskiy almost 3 years ago

GSUP: introduce new messages for SS/USSD payloads

In order to be able to transfer SS/USSD messages via GSUP,
this change introduces the following new message types:

- OSMO_GSUP_MSGT_PROC_SS_*,

and the following new IE:

- OSMO_GSUP_SS_INFO_IE

which represents an ASN.1 encoded MAP payload coming to/from
the mobile station 'as is', without any transcoding.

Change-Id: Ie17a78043a35fffbdd59e80fd2b2da39cce5e532
Related: OS#1597

History

#1 Updated by laforge over 3 years ago

  • Assignee set to fixeria

#2 Updated by laforge over 3 years ago

  • Project changed from OsmoNITB to OsmoMSC

#3 Updated by fixeria about 3 years 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.

https://gerrit.osmocom.org/7600/

#4 Updated by fixeria about 3 years ago

Found a few great pictures about MAP message flow.

User-initiated session example

Network-initiated session example

#5 Updated by fixeria about 3 years ago

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

#6 Updated by fixeria about 3 years 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:

https://wiki.wireshark.org/SampleCaptures?action=AttachFile&do=get&target=gsm_map_with_ussd_string.pcap

but one is too trivial...

#7 Updated by fixeria about 3 years ago

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

https://telestax.com/blog/telscale-ussd-gateway-achieves-700-ussd-messagessec/

This is exactly from where I took the pictures above.

#8 Updated by laforge about 3 years ago

#9 Updated by fixeria about 3 years ago

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

The images are created using https://draw.io, and can be opened
and edited (source XML attached) there.

#10 Updated by fixeria almost 3 years 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:

https://gerrit.osmocom.org/9658/
https://gerrit.osmocom.org/9661/

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 almost 3 years 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 almost 3 years ago

  • Tags set to USSD

#13 Updated by laforge almost 3 years ago

#14 Updated by fixeria almost 3 years ago

  • Status changed from Feedback to Stalled

#15 Updated by fixeria over 2 years ago

  • Checklist item Processing / forwarding of the Cause IE in GSM 04.80 RELEASE COMPLETE message added
  • Checklist item Processing of SS Version IE in MO GSM 04.80 REGISTER message added
  • Priority changed from Normal to Low

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