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Feature #5679

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unsupported SCCP user primitive N-PCSTATE.indication

Added by pespin 18 days ago. Updated 17 days ago.

Status:
Feedback
Priority:
Normal
Assignee:
Target version:
-
Start date:
09/12/2022
Due date:
% Done:

0%

Spec Reference:

Description

As seen in osmo-hnbgw when receiving an M3UA NTFY:

20220912180716266 DLINP <0007> stream.c:445 [CONNECTED] osmo_stream_cli_fd_cb(): connected read
20220912180716266 DLINP <0007> stream.c:324 [CONNECTED] osmo_stream_cli_read(): message received
20220912180716267 DLSS7 <0011> osmo_ss7.c:1906 0: asp-asp-clnt-msc-0: xua_cli_read_cb(): sctp_recvmsg() returned 24 (flags=0x80)
20220912180716267 DLM3UA <0014> m3ua.c:714 0: asp-asp-clnt-msc-0: Received M3UA Message (SNM:DAVA)
20220912180716267 DLM3UA <0014> xua_snm.c:403 0: asp-asp-clnt-msc-0: Rx DAVA() for 0.23.4/0,
20220912180716267 DLSCCP <0012> sccp_user.c:175 Delivering N-PCSTATE.indication to SCCP User 'SCCP Management' 
20220912180716267 DLSCCP <0012> sccp_scmg.c:298 unsupported SCCP user primitive N-PCSTATE.indication     <======= libosmo-sccp.git  scmg_prim_cb()
20220912180716267 DLSCCP <0012> sccp_user.c:175 Delivering N-PCSTATE.indication to SCCP User 'OsmoHNBGW' <===== IT IS FURTHER DELIVERED UPWARDS DESPITE NOT BEING SUPPORTED?
20220912180716267 DMAIN <0000> hnbgw_cn.c:473 sccp_sap_up(N-PCSTATE.indication)
20220912180716267 DMAIN <0000> hnbgw_cn.c:504 Received unknown prim 2562 from SCCP USER SAP  <===== OSMO_HNBGW DOESN'T KNOW WHAT TO DO WITH IT

laforge would you mind providing feedback on what you think would need to be done here?


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Actions #2

Updated by pespin 18 days ago

That's actually coming from a DAVA according to logs, but I only see 1 DAVA in pcap while I 2 arriving in osmo-hnbgw. Maybe it's because osmo-stp is sending 2 of them and I don't see osmo-stp<->osmo-hnbgw traffic in there.

Actions #3

Updated by pespin 18 days ago

Rx of DUNA also triggers similar path in libosmo-sccp and osmo-hnbgw, printing same error log messages.

Actions #4

Updated by laforge 18 days ago

In general it makes sense to notify the user of point code availability / unavailability.

I just don't know exactly what the correct primitive for this would be at the SCCP user SAP. If
the ITU specs for SCCP state that N-PCSTATE.ind is to be used for this, great.

The user (application) could use this information to trigger state transitions. Maybe we should
simply silently discard it if we don't implement it.

The warnings about unsupported primitives were first, and later libosmo-sigtran got support for DUNA/DAVA
processing, creating those warnings.

Actions #5

Updated by pespin 17 days ago

IIUC according to ITU Q.714 5.3.6.4 - 5.3.6.6, N-PCSTATE Indication is used to "inform local allowed concerned SCCP subsystems".

ITU Q.711 6.3.2, 6.3.2.3.3 also mentions it.

IIUC currently the primitive is sent once to the internal scmg layer and afterwards up to the SCCP user stack reaching osmo-hnbgw code.

Actions #6

Updated by laforge 17 days ago

Hi Pau,

On Tue, Sep 13, 2022 at 11:58:32AM +0000, pespin wrote:

IIUC according to ITU Q.714 5.3.6.4 - 5.3.6.6, N-PCSTATE Indication is used to "inform local allowed concerned SCCP subsystems".

ok. As those point codes are the point codes relevant to osmo-hnbgw, this is correct.

osmo-hnbgw should handle them or ignore them.

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