help need with the silent_call function in OsmoMSC/BSC

This is merely a historical archive of years 2008-2021, before the migration to mailman3.

A maintained and still updated list archive can be found at https://lists.osmocom.org/hyperkitty/list/OpenBSC@lists.osmocom.org/.

Neels Hofmeyr nhofmeyr at sysmocom.de
Mon Oct 15 10:57:08 UTC 2018


On Fri, Oct 12, 2018 at 04:35:04PM +0100, Mihai Ordean wrote:
> Now I want to enable the silent_call functionality to begin testing but
> I can't seem able to do so.

Historically, the silent call feature was an important part of the Osmocom
heritage: IIRC demonstrating a silent call to locate a phone was one of the
important early goals of implementing osmo-nitb aka bsc_hack in the first
place, and from there things have evolved to the multi component externally
compatible stack we have today.

But, these days, I don't know of anyone testing on a regular basis whether
silent call works, be it manually or automatically. Typically that is a
guarantee for bit rot and breakage.

I'm fairly certain that is, sadly, the case with the silent call feature. It
should work, but one refactoring or the other has broken it.

Looking at the log, I believe the fix is fairly trivial:

Today's MSC strictly monitors connections by subscribers, and first ensures
they get accepted (in terms of authentication), and then ensures that they
establish some sort of meaningful request/response interaction.

So I think all we need is that in paging_cb_silent(), we transition the conn
FSM from SUBSCR_CONN_S_ACCEPTED to SUBSCR_CONN_S_COMMUNICATING, to stop the
timer that watches validity. See msc_subscr_conn_communicating().

It would be excellent if you could try to implement and test yourself. If you
need help, do ask again.

~N

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: not available
URL: <http://lists.osmocom.org/pipermail/openbsc/attachments/20181015/145714a3/attachment.bin>


More information about the OpenBSC mailing list