3 Background Processes

This chapter explains the processes that are started automatically by Service Logic Execution Environment (SLEE).

Note: This chapter also includes some plug-ins to background processes which do not run independently.

vssp

vssp is the binary that runs the UCAI application.

No other binaries are installed with UCAI.

Startup

This task is started by the SLEE, by the following lines in SLEE.cfg: 

INTERFACE=VSSP vssp.sh /IN/service_packages/VSSP/bin
EVENT

Notes:

The actual startup script name may vary.

If you configured UCAI to run without the SLEE, you can also start UCAI from the command line.

Configuration

vssp accepts the following parameters from vssp.config. 

unset option slee. 
set option syslog. 
set option stats. 
set cdr file="filename"; 
set option debug. 
set option mtp debug. 
set option stats. 
set option overload backoff period to 1 seconds; 
set startup time seconds. 
set network network_identifier. 
filter iam drop [{number,} number and] number.
connect circuit to circuit [for number_of_circuits].

M3UA configuration

vssp supports these parameters from m3ua.config. 

asp 
port port 
addrs {ip_address} 
; 
sgp itp1  
port port 
addrs {ip_address} 
; 
gateway sg1 
{ 
sgp itp1 key int; 
pc {int, [int, ...]}; 
} 
as  
; 
pc int  
gateway {sg1}

Command line parameters

vssp supports the following command line parameters:

Note: These parameters are usually specified in the startup script, vssp.sh.

vssp -c configuration_file [-k keyfile] [-m m3ua_config_file]

where:

Parameter Description
-c configuration_file The path and name of the vssp configuration file.
-k keyfile

The path and name of the keyfile file, which sets the maximum number of circuits UCAI can use.

The default is a file named keyfile in the same directory as the vssp configuration file.

-m m3ua_config_file

The path and name of the M3UA configuration file.

The default is a file named m3ua.config in the same directory as the vssp configuration file.

Standard options

The following parameters are available for all types of UCAI installation.

cdr file

Syntax: set cdr file="filename";
Description: When set, defines the directory and filename to which vssp logs CDRs.
Type: String
Optionality: Optional (default used if not set)
Allowed:  
Default: Not set
Notes: The equals sign (=) is optional.
Examples:

set cdr file="cdr.log";

set cdr file "cdr.log";

connect

Defines the circuit loops for vssp. For more information about configuring circuit loops, see Configuring circuit loops .

Default: none
Allowed: connect circuit to circuit[ for number of_circuits][ except cic[ and cic]].
Note: The full stop or semi-colon on the end is essential if you are not specifying a number of circuits.

debug

Turns vssp debug output on or off. If enabled, an operator can debug SSP functionality, as well as lower-level ISUP functionality.

The SSP functionality details how calls are being progressed and the ISUP debugging prints out all the ISUP messages sent and received.

Default: off
Format: set option debug
Notes: This output is sent out on the debugging output of the VSSP (stdout).

filter

Drops specified parameters within an IAM. Drops the parameters with the name value of any of the given numbers on an outgoing IAM message.

Default: empty set
Format:

filter iam drop [{ number ,} number and] number

Where:

  • Square brackets enclose optional entries
  • Curly brackets enclose zero or more entries
Note: Mandatory parameters cannot be dropped.

limit

Sets a CAPS limit on vssp. The first number is the CAPS limit and the second is the release cause to be used if the CAPS limit is exceeded.

Default: Cause defaults to 42.
Format: 
set option limit to number caps cause
[cause_number]
Notes:

The to can be replaced with an equals sign.

cause_number is optional.

mtp debug

Turns mtp traffic output from vssp on or off. If on, a hexadecimal representation of all the ISUP messages is written to the vssp’s debugging output (stdout).

Default: off
Format: set option mtp debug

network

Sets the network identifier in the MTP3 header to be the specified value.

Default: 2
Note:

This only applies to the M3UA and Data Kinetics stacks.

2 is national network.

set ica iam cpc

Sets the calling party category on the legs of ICA calls. The CPC can be set on just the A-leg or on both legs.

Default: none
Format: 
set ica iam cpc A-leg_number
[B-leg_number]

Where:

  • number is the override value for the calling party category.
Notes:

By default, the CPC set for the A-leg number will be used for the B-leg.

There is an Convergent Charging Controller extension to INAP that allows the CPC to be set on the A-leg of an ICA-created call.

Service logic may override a set B-leg value.

overload backoff period

Syntax: 
set option overload backoff period = int
seconds;
Description: Sets the time period in seconds during which vssp rejects new requests to create a SLEE dialog and returns an error.
Default: 1
Allowed values: 0 to 4294967295
Notes:
  • vssp marks itself as overloaded and rejects new initial address messages (IAMs) for the configured backoff period, when it fails to create a SLEE dialog.
  • 0 means no overload limit.
Example: 
set option overload backoff period = 10
seconds;

slee

Enable or disable the interface between vssp and the SLEE. If the SLEE interface is disabled, vssp acts simply as a call router, in effect providing a null service.

Default: on
Format: unset option slee
Note: This option should only be used for debugging.

startup time

Seconds vssp takes to reset all its circuits at start up.

Default: 15
Allowed: number
Format: set startup time = seconds
Note:

If there are a large number of circuits, the default may need to be increased to avoid temporary congestion of the network.

The equals sign (=) is optional.

stats

If set, vssp will log a basic calculation of the number of calls being processed by vssp per second.

Default: off
Format: set option stats

syslog

Send error messages to the syslog as well as UNIX stderr.

Any errors will now be logged to syslog. The syslog identifier is set to VSSP, the facility is set to LOG_USER and errors are logged at level LOG_ERR.

Default: off
Format: set option syslog

M3UA parameters

The M3UA configuration uses a cascading definition structure. The first parameter (file) is defined by four other parameters. Those four parameters are in turn defined by other parameters set later in the file.

For more information about how these parameters work together to configure vssp, see M3UA Configuration .

vssp supports these parameters from the m3ua.config file.

Note:

These parameters are only available if you have installed the M3UA version of UCAI.

as

Application Server definition. Assigns ASPs to ASs.

Default:  
Syntax:

as pc number gateway { gateway_list };

Where:

  • number is the Point Code number of the AS
  • gateway_list is the list of SGs the AS is peered with.
Note:  

asp

Defines the local ASP.

Default:  
Syntax:
asp port port 
addrs
{
ip };

Where:

  • port is the port the AS process is running on
  • ip is the IP address the AS process is running on

gateway

Gateway definitions.

Default:  
Syntax:

gateway identifier

{

sgp itp1 key keypc { pcs };

}

Where:

  • identifier is a unique identifier
  • key is a keyed_sgsp parameter
  • pcs is a list of comma separated point codes

sgp

Signalling Gateway Process definitions.

Default:  
Syntax:
sgp itp1 port port 
addrs
{
ip };

Where:

  • port is the port the SG process is running on
  • ip is the IP address the SG process is running on

Example configuration

This is an example of the vssp.config file (comments have been removed). 

 set option slee. 
set option syslog. 
set option stats. 
set cdr file="cdr.log"; 
#set option debug. 
#set option mtp debug. 
set ica iam cpc 10; 
connect 1/2/1 to 1/2/17 for 15;

Example M3UA configuration file

This text shows an example M3UA configuration:

#start file 
asp port 6969 addrs {192.168.26.117}; 
sgp itp1 port 2905 addrs {192.168.26.215}; 
gateway sg1 
{ 
sgp itp1 key 6969; 
pc {999, 4805, 4807}; 
} 
as pc 4701 gateway {sg1}; 
#end file

Using more whitespace, this file could also be displayed as follows:

#start file 
asp  
port 6969  
addrs {192.168.26.117} 
; 
sgp itp1  
port 2905  
addrs {192.168.26.215} 
; 
gateway sg1 
{ 
sgp itp1 key 6969; 
pc {999, 4805, 4807}; 
} 
as  
pc 4701  
gateway {sg1} 
; 
#end file

Output

vssp writes error messages to the system messages file, and also writes additional output to the following default:

/IN/service_packages/VSSP/output/outputFile.log

Note: May vary as per configuration in the startup script.