Hi Mychaela and List,

I am not sure how osmocom's internal routing for media is set up before conversion to SIP. From what I have seen, if you want to connect with a landline provider/ILEC, they still expect you to be able to do interconnection for signalling and media over TDM links, which I do not believe that osmocom supports. Additionally, from my reading of the documentation, osmoMSC interconnects with it's HLR and with the sip connector over it's own internal GSUP and MNCC protocols, as opposed to sigtran or diameter, which are what I believe I would need to use for interconnection. I could be wrong about this however. The suggestion to check out GSUP for the SMS bridging side is very helpful though. I hadn't known about this, and I'll certainly look into it more if I do end up building a SMS bridge.

On another note, I know that you have done some research on getting access to carrier sms providers. From my reading, the major companies that provide this service are Orange, Syniverse, Arelion, Comphone, and UniFi communications (this one, not the access point company). Have you reached out to any of them? Do you have any information how they might respond to a 'hobbyist' request like this? You might also want to check out this link for a brief overview of getting recognized as a cell company in the US, assuming that you haven't seen it already. It looks like all you have to do is file the form 499-A with the business that you want to be registered as the communications company.

Thank you,

Enzo Damato

On 8/27/23 14:06, Mychaela Falconia wrote:
Hi Enzo,


This is about what I thought for calls, using sip connector to a 
yate switch, and then using yate to signal over ss7.

The big downside of this approach is a needless lossy conversion,
taking an unnecessary hop via SIP.  GSM call control is very close to
Q.931/ISUP, thus a native converter between these two would be very
clean and beautiful.  If you are able (in terms of dollar cost and
political ability, not technical) to connect to PSTN via native
SS7/ISUP rather than SIP, then why would you want to go from GSM CC to
SIP and then back to ISUP?

In September OsmoDevCall I will be presenting my alternative solution
that eliminates osmo-sip-connector and replaces it with highly custom,
single-purpose-made software specifically for interconnecting an
Osmocom network to PSTN.  Right now it is PSTN-via-SIP, but if someone
is able (politically/economically) to eliminate the SIP part altogether
and replace it with native SS7/ISUP, I would be delighted to get an
opportunity to extend my software to that configuration.


I am assuming that directly connecting to another 
provider for sms message exchange over SS7 would be impossible with the 
currently implemented feature set in osmoSMSC?

As a nitpick, right now there does not exist a separate software
component named OsmoSMSC, instead in stock Osmocom CNI sw the SMSC
function is absorbed into OsmoMSC.  I and Vadim (fixeria) have been
discussing how to improve this situation, and there is some ongoing
work.


Do you think it would be 
possible build some form of bridge between yate or some other SMS 
program and the osmoSMSC using SMPP?

Someone else would have to answer about the Yate part, but on the
Osmocom CNI side, SMPP is not the only way to get SMS into and out of
Osmocom.  The other way is SMS via GSUP, which is a much more native
access to SM-RL (the Relay Layer of SMS-PP) between a GSM MS and an
SMSC:

https://osmocom.org/issues/3587

In the current state of Osmocom this support is still incomplete, but
I am actively working on making it complete:

https://osmocom.org/issues/6135

M~