Hello, I'm setting up an Asterisk connection with osmo-sip-connector.
Initiation of calls works fine, but no sound is getting through.
My setup is as follows:
Local computer is running all osmo software plus asterisk
interface has IP address 192.168.27.49 plus 192.168.27.47 as alias
femtocell is at 192.168.27.41
osmo-mgw.cfg
mgcp bind ip 192.168.27.49 rtp port-range 4002 16000 rtp bind-ip 192.168.27.47
osmo-sip-connector.cfg
sip local 192.168.27.47 5069 remote 192.168.27.49 5060
osmo-msc.cfg
msc mgw remote-ip 192.168.27.49 mgw remote-port 2427 mgw local-port 2728
When I start wireshark it only shows packets flowing between 192.168.27.41(femtocell) and 192.168.27.47(osmo-mgw).
No packets to/from Asterisk server, how can I fix this problem? Current documentation on osmo-mgw is quite difficult to understand.
Hi,
First of all, the problem you will face with 3G is IuUP. 3G adds, *inside* the RTP payload, another header and also mangles the AMR bits incompatibly, which we do not decode yet. That is why voice calls between 3G works (only because we forward the IuUP between the femto cells directly) and 3G <-> {2G,SIP} do not work. IuUP is supposed to terminate at the MGW.
We have a little bit of work started on IuUP, but it is still quite far from done and also has no high priority at the moment.
If you have a pressing need you could implement it or sponsor someone to do so. Let me know and I can give you some pointers.
Also, you need to set up external MNCC. Your mail hints osmo-sip-connector, so I assume you're doing that, but if you're not seeing *any* packages to/from SIP, then your MSC might still be doing internal MNCC.
No packets to/from Asterisk server, how can I fix this problem? Current documentation on osmo-mgw is quite difficult to understand.
The MGW is told by the MSC what to do, there is nothing you can configure there except the connection where the MSC talks to it. Think of it like a plain dumb switching board, and the operator plugging the cables is the MSC.
~N
I see, some information about IuUP certainly wouldn't hurt, for the good of all of us.
Also, you need to set up external MNCC. Your mail hints osmo-sip-connector, so I assume you're doing that, but if you're not seeing *any* packages to/from SIP, then your MSC might still be doing internal MNCC.
Is there anything else to do other than the -M flag? And to clarify, SIP works normally, even the DTMF signals go through, it's just the RTP packets that are missing.
Regards,
Pierre
On Mon, Nov 19, 2018 at 11:50:59PM +0900, Pierre Kim wrote:
I see, some information about IuUP certainly wouldn't hurt, for the good of all of us.
/me digs up older post:
So far I know of 3GPP TS 25.414, 5.1.3.3.2 RTP Payload: "A single Iu UP PDU, as described in TS 25.415 [24], shall be transported as RTP payload."
And 25.415 contains the juicy bits.
We have osmo-mgw branch neels/iuup refactoring some RTP packet handling to be able to easily strip/insert an IuUP header with correct checksums etc., and we have libosmocore branch laforge/iu_up implementing a state machine about unshuffling the payload bits. I guess to get a working solution we would need to marry those two branches and fix whatever is still broken/not implemented in there. They are still potentially wildly incompatible.
Is there anything else to do other than the -M flag? And to clarify, SIP
I wish someone more familiar with external MNCC would take over here. Anyone?
If I were alone on this, I would try to decipher the MGCP messages between MSC and MGW-for-MSC (CRCX, MDCX), and see whether it instructs the MGW to send towards SIP. And look at MSC debug logging. Not sure if that's the easiest way.
~N
-
Neels Hofmeyr -
Pierre Kim