14 Dec
2018
14 Dec
'18
10:51 a.m.
Dear Osmocom community,
Did somebody try to use nano3g ip.access femtocells and Osmocom system with
external call handling? What I am trying to do is to make calls work between
VoIP phones connected to PBX and UEs connected to Osmocom system. I've tried two
PBXs: Kamailio with rtpengine and Asterisk. Signalling worked good between VoIP
phone and UE with both PBXs; calls between two UEs registered on Osmocom system
worked good also... But I fail to do transcoding (calls between VoIP phone and
UE). The problem is that it is unknown which codec is used by nano3g ip.access
femtocell.
So, the question is: Do you know what codecs were used for speech in your setup
with nano3g ip.access femtocells? Or do you know how to find out that
information? (It was stated by ip.access that they use AMR but I failed to match
AMR specs with RTP payload that was sent by femtocell...).
I would be very grateful for any ideas.
Kind regards, Mykola
14 Dec
14 Dec
11:05 a.m.
Dear Mykola,
PBX (like asterisk) not support amr, try using TCHF/TCHH (not AMR).
see this : https://community.asterisk.org/t/support-for-amr-codec/73659
hope this help!
On Fri, Dec 14, 2018 at 4:51 PM Mykola Shchetinin <mykola(a)kingmuffin.com>
wrote:
Dear Osmocom community,
Did somebody try to use nano3g ip.access femtocells and Osmocom system with
external call handling? What I am trying to do is to make calls work
between
VoIP phones connected to PBX and UEs connected to Osmocom system. I've
tried two
PBXs: Kamailio with rtpengine and Asterisk. Signalling worked good between
VoIP
phone and UE with both PBXs; calls between two UEs registered on Osmocom
system
worked good also... But I fail to do transcoding (calls between VoIP phone
and
UE). The problem is that it is unknown which codec is used by nano3g
ip.access
femtocell.
So, the question is: Do you know what codecs were used for speech in your
setup
with nano3g ip.access femtocells? Or do you know how to find out that
information? (It was stated by ip.access that they use AMR but I failed to
match
AMR specs with RTP payload that was sent by femtocell...).
I would be very grateful for any ideas.
Kind regards, Mykola
--
Best Regards,
Sandi
11:12 a.m.
Change on your config on osmo-bsc, osmo-msc to change the codec.
example :
(osmo-bsc)
msc 0
ip.access rtp-base 25000
no bsc-welcome-text
no bsc-msc-lost-text
no bsc-grace-text
type normal
allow-emergency allow
codec-list fr1
amr-config 12_2k forbidden
amr-config 10_2k forbidden
amr-config 7_95k forbidden
amr-config 7_40k forbidden
amr-config 6_70k forbidden
amr-config 5_90k forbidden
amr-config 5_15k forbidden
amr-config 4_75k forbidden
mgw remote-ip 127.0.0.1
mgw remote-port 2427
mgw endpoint-range 1 31
mgw local-ip 127.0.0.1
(osmo-msc)
mncc-int
default-codec tch-f fr
default-codec tch-h hr
On Fri, Dec 14, 2018 at 5:07 PM Mykola Shchetinin <mykola(a)kingmuffin.com>
wrote:
--
Best Regards,
Sandi
try using
TCHF/TCHH (not AMR)
and how do one tell the femtocell to use that?
11:16 a.m.
Thank you for the help.
Though we don't have osmo-bsc as we have 3g only network (osmo-hnbgw) and
the parameters you've written for osmo-msc seem to work for internal call
handling only (as far as I know) whilst I use osmo-sip-connector to connect
to PBX...
11:20 a.m.
it should be the same for osmo-msc, it connect to osmo-sip-connector too
via /tmp/bsc_mncc om msc site.
did you add these parameter to connect mncc to osmo-sip?
On Fri, Dec 14, 2018 at 5:16 PM Mykola Shchetinin <mykola(a)kingmuffin.com>
wrote:
Thank you for the help.
Though we don't have osmo-bsc as we have 3g only network (osmo-hnbgw) and
the parameters you've written for osmo-msc seem to work for internal call
handling only (as far as I know) whilst I use osmo-sip-connector to connect
to PBX...
--
Best Regards,
Sandi
4:28 p.m.
Hi Mykola,
that talk about AMR in this thread is completely moot when we're talking IuCS
and nano3G.
The point is that IuCS doesn't talk plain RTP, it talks IuUP inside the RTP
payload (!). That is another header, and the AMR bits inside that are mangled
and shifted around, even though the underlying codec is still AMR.
We are also talking about that as we are gearing up for congress. Not so long
ago on this mailing list we have talked about IuUP, and the two branches that
are half finished work towards de-/encapsulating IuUP when talking to 3G.
So far 3G <-> 3G voice calls work only because we directly pass through the
IuUP (with a pretty mad header hack) and then both ends understand to extract
the voice from it.
As soon as you want to go 3G <-> 2G or 3G <-> PBX, it's a lost cause
without
IuUP decoding, e.g. in OsmoMGW.
~N
4:35 p.m.
Copying another mail I wrote on another list:
"
I've been asked about IuUP specs.
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.
"
~N
5:30 p.m.
Hello Neels,
Thank you very much. It explains a lot!
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.
And can I ask what the status/priority of this work is? When do you want/expect
to get this working?
Is there any way we could support that?
Kind regards,
Mykola
16 Dec
16 Dec
5:42 p.m.
On Fri, Dec 14, 2018 at 06:30:50PM +0200, Mykola Shchetinin wrote:
And can I ask what the status/priority of this work
is? When do you want/expect
to get this working?
The prio is hobby / contribution. There is no funding for that presently. But
being able to decode it is very desirable from the community POV. It would
allow 2G/PBX+PSTN interop, early media: important for a non-lab installation.
We might try to get it working for the 35c3 congress, but we might just disable
3G (as opt-in) if 3G voice cannot work, to improve the user experience.
Is there any way we could support that?
As always, you can contribute code, or you can fund development. Fund either
own developer(s) and contribute to gerrit, or book e.g. from sysmocom. I think
we should be able to take that on in early 2019, but rather ask sales@.
~N
--
- Neels Hofmeyr <nhofmeyr(a)sysmocom.de> http://www.sysmocom.de/
=======================================================================
* sysmocom - systems for mobile communications GmbH
* Alt-Moabit 93
* 10559 Berlin, Germany
* Sitz / Registered office: Berlin, HRB 134158 B
* Geschäftsführer / Managing Directors: Harald Welte
17 Dec
17 Dec
5:41 p.m.
Hello Neels,
As always, you can contribute code, or you can fund
development. Fund either
own developer(s) and contribute to gerrit, or book e.g. from sysmocom.
Understood. I will try to make it work. Though I don't promise anything as I see
this code the first time unlike you and Harald :)
Regards,
Mykola
18 Dec
18 Dec
1:38 p.m.
On Mon, Dec 17, 2018 at 06:41:31PM +0200, Mykola Shchetinin wrote:
Hello Neels,
Feel free to ping on IRC: FreeNode #osmocom any time.
In case we try anything for congress it would be good to keep in touch.
~N
As always, you can contribute code, or you can
fund development. Fund either
own developer(s) and contribute to gerrit, or book e.g. from sysmocom.
Understood. I will try to make it work. Though I don't promise anything as I see
this code the first time unlike you and Harald :)
2392
days inactive
2396
days old
12 comments
4 participants
participants (4)
-
Mykola Shchetinin -
Mykola Shchetinin -
Neels Hofmeyr -
Sandi Suhendro