== Running OsmoMSC

The OsmoMSC executable (`osmo-msc`) offers the following command-line
arguments:

=== SYNOPSIS

*osmo-msc* [-h|-V] [-d 'DBGMASK'] [-D] [-c 'CONFIGFILE'] [-s] [-T] [-e 'LOGLEVEL'] [-l 'DATABASE'] [-M 'SOCKETPATH'] [-C]

=== OPTIONS

*-h, --help*::
	Print a short help message about the supported options
*-V, --version*::
	Print the compile-time version number of the OsmoBTS program
*-d, --debug 'DBGMASK','DBGLEVELS'*::
	Set the log subsystems and levels for logging to stderr. This
	has mostly been superseded by VTY-based logging configuration,
	see <<logging>> for further information.
*-D, --daemonize*::
	Fork the process as a daemon into background.
*-c, --config-file 'CONFIGFILE'*::
	Specify the file and path name of the configuration file to be
	used. If none is specified, use `openbsc.cfg` in the current
	working directory.
*-s, --disable-color*::
	Disable colors for logging to stderr. This has mostly been
	deprecated by VTY based logging configuration, see <<logging>>
	for more information.
*-T, --timestamp*::
	Enable time-stamping of log messages to stderr. This has mostly
	been deprecated by VTY based logging configuration, see
	<<logging>> for more information.
*-e, --log-level 'LOGLEVEL'*::
	Set the global log level for logging to stderr. This has mostly
	been deprecated by VTY based logging configuration, see
	<<logging>> for more information.
*-l, --database 'DATABASE'*::
	Specify the file name of the SQLite3 database to use as SMS storage
*-M, --mncc-sock-path*::
	Enable the MNCC socket for an external MNCC handler. See
	<<mncc>> for further information.
*-m, --mncc-sock*::
	Same as option -M (deprecated).
*-C, --no-dbcounter*::
	Disable the regular periodic synchronization of statistics
	counters to the database.


=== Multiple instances

Running multiple instances of `osmo-msc` is possible if all interfaces (VTY,
CTRL) are separated using the appropriate configuration options. The IP based
interfaces are binding to local host by default. In order to separate the
processes, the user has to bind those services to specific but different IP
addresses.

The VTY and the Control interface can be bound to IP addresses from the loopback
address range, for example:

----
line vty
 bind 127.0.0.2
ctrl
 bind 127.0.0.2
----

If external SMPP is enabled, you may bind it to a different interface using:

----
smpp
 local-tcp-ip 10.23.42.1 2775
----

More on SMPP configuration in <<smpp-config-global>>.

The external MNCC handler is configured by the `--mncc-sock` commandline
argument. Choose a different such socket path for each OsmoMSC instance running
on the same file system. See more in <<mncc-external>>.

For the following links, OsmoMSC acts as a client and does not listen/bind to a
specific interface, and will hence not encounter conflicts for multiple instances
running on the same interface:

- The SCCP/M3UA links are established by OsmoMSC contacting an STP.
- The GSUP link is established by OsmoMSC contacting an HLR.


=== Configure primary links

==== Configure SCCP/M3UA to accept _A_ and _IuCS_ links

OsmoMSC will contact an STP instance to establish an SCCP/M3UA link. BSC and
HNBGW will then reach the MSC via this link. By default, an STP instance is
assumed to listen on the default M3UA port (2905) on the local host.

Establishing an SCCP/M3UA link towards an STP instance not on the local host
can be configured as follows:

----
cs7 instance 0
 asp my-OsmoMSC 2905 0 m3ua
  ! IP address of the remote STP:
  remote-ip 10.23.24.1
----

Note that _A_ and _IuCS_ may use different SCCP instances, if so desired:

----
cs7 instance 0
 asp my-OsmoMSC-A 2905 0 m3ua
  remote-ip 10.23.42.1
cs7 instance 1
 asp my-OsmoMSC-Iu 2905 0 m3ua
  remote-ip 10.23.42.2
msc
 cs7-instance-a 0
 cs7-instance-iu 1
----

A full configuration needs an `asp` on an `as` -- an Application Server Process
running on an Application Server -- as well as a local point code and routing
configuration. The SCCP VTY automatically creates those parts that are missing,
by assuming sane defaults. A complete configuration would look like this:

----
cs7 instance 0
 point-code 0.23.1
 asp my-OsmoMSC-A-Iu 2905 0 m3ua
  remote-ip 127.0.0.1
 as my-as-for-OsmoMSC-A-Iu m3ua
  asp my-OsmoMSC-A-Iu
  routing-key 0 0.23.1
----

==== Configure GSUP to reach the HLR

OsmoMSC will assume a GSUP server (OsmoHLR) to run on the local host and the
default GSUP port (4222). Contacting an HLR at a different IP address can be
configured as follows:

----
hlr
 ! IP address of the remote HLR:
 remote-ip 10.23.42.1
 ! default port is 4222, optionally configurable by:
 remote-port 1234
----