9 Oct
2012
9 Oct
'12
2:57 p.m.
On Mon, Oct 08, 2012 at 09:23:58PM +0200, Yann R. Moupinda wrote:
Hello everyone,
thanks for the ideas you gave me about how i can learn more about the communication
between BSC and MSC in my sysmoBTS. Since last week i've been looking at the source
codes and it's still difficult for me to follow the exchanged messages betwenn BSC and
MSC. I don't have high programming skills.
well, it starts with the organisation of the sourcecode. E.g. src/libmsc
contains the MSC functionality. E.g. take a look at osmo_msc.c it is glueing
the "BSC API" to the MSC code.
compl_layer3 (as of GSM 08.08) will be called for the first message on
a newly opened RF connection.
dtap will be called for every following message.
Instead of using sysmoBTS as an autonomous self-contained GSM network (NITB mode),
i'd like to configure it in the BSC-only mode running the osmo-bts and osmo-bsc. I
read that i will need a MSC that can provide an A-over-IP interface using SCCP-lite. I saw
that the "on-waves/bsc-master" branch is implementing such a SCCP and works have
been done to create a GSM0808 like API and move the MSC code inside OpenBSC over to use
this API. So i was wondering how far this project has been developed yet. Do you already
have any interesting results that can help me? If not, it can be also interesting for me
to know how you did your tests by implementing the bsc-only mode (osmo-bsc)? Did you
connect it to a real MSC or did you have anything else emulating the MSC/HLR/VLR/EIR
functions?
on-waves/bsc-master is an old vendor branch, the same functionality is
available in the master branch of openbsc. The src/osmo-bsc directory
holds the BSC implementation. This adds GSM 08.08 parsing and message
generation on top of the 'BSC API' (same interface as in osmo_msc.c but
different implementation).
The osmo-bsc has been used with various proprietary MSCs. There is no
free MSC that will just do what you want at this point in time. I have
the start of a MSC in Smalltalk but right now it is solving a non-standard
usecase and is not a general MSC.
Why do you need to see GSM 08.08 messages?