SigtranApp

SIGTRAN Application Configuration

The SIGTRAN Application is responsible for communication with all external SIGTRAN (SUA or M3UA) end points.

A single SIGTRAN Application is capable of connecting to multiple end nodes (e.g. two STP nodes in a redundant pair). Each remote node may have multiple (redundant) endpoints.

It should only be necessary to configure multiple SIGTRAN Application instances if you wish a single N2SVCD to communicate with two separate environments - e.g. with a “Test” environment and with a “Pre-Production” environment.

Here is an SUA configuration example, operating in connect (client) mode.

<?xml version="1.0" encoding="utf-8"?>
<n2svcd>
  ...
  <applications>
    ...
    <application name="SIGTRAN" module="SigtranApp">
      <include>
        <lib>../apps/sigtran/lib</lib>
      </include>
      <parameters>
        <parameter name="ossn" value="12"/>
        <parameter name="ogt_digits" value="6421600000"/>
        <parameter name="ogt_noa" value="4"/>
        <parameter name="ogt_np" value="1"/>
        <parameter name="ogt_tt" value="0"/>
      </parameters>
      <config>
        <connections>
          <connection name="peer-2057" type="sua" mode="connect" role="as">
            <remote_host>10.42.2.155,10.42.3.155</remote_host>
            <remote_port>14001</remote_port>
            <local_host>10.42.2.100</local_host>
            <local_port>15000</local_port>
          </connection>
        </connections>
        <routes>
          <route pc="2057" connection="peer-2057"/>
          <route mingt="6421600000" maxgt="6421699999" connection="peer-2057"/>
        </routes>
      </config>
    </application>
    ...
  </application>
  ...
</n2svcd>

The SIGTRAN Application can also be run in a “Loopback” mode which is ideal for quick testing of TCAP/INAP functionality without requiring SCTP. A Loopback example is as follows:

<?xml version="1.0" encoding="utf-8"?>
<n2svcd>
  ...
  <applications>
    ...
    <application name="SIGTRAN" module="SigtranApp">
      <include>
        <lib>../apps/sigtran/lib</lib>
      </include>
      <parameters>
        <parameter name="opc" value="4114"/>
        <parameter name="ossn" value="10"/>
      </parameters>
      <config>
        <connections>
          <connection name="Loopback" type="loopback"/>
        </connections>
        <routes>
          <route pc="4114" connection="Loopback"/>
        </routes>
        <handlers>
          <handler ssn="106" application="IN Script Service"/>
        </handlers>
      </config>
    </application>
    ...
  </application>
  ...
</n2svcd>

Configuration Details

In addition to the common Application configuration parameters, the application element attributes for a SIGTRAN Application instance may include the below. For details of the various parameter types used, refer to Common Configuration.

Parameter Name Type XML Type Description
module String Attribute [Required] SigtranApp
include.lib String Attribute [Required] ../apps/sigtran/lib
parameters Array Element [Required] As per Common Configuration Application parameters.
.edr_enabled - - This value is ignored; the SIGTRAN Application does not support writing EDRs.
.correlation_id_len Integer Attribute The number of digits for each CorrelationID in the ID Pool.
Needed for SCP nodes only. Default is not to create a CorrelationID pool.
(Range = 0, 2-8, Default = 0)
.correlation_id_min Integer Attribute The minimum value of CorrelationID in the ID Pool.
This is only required when running an SCP with multiple SIGTRAN apps that are both using same CorrelationID Length (to avoid range conflict).
(Range = 0-[all-9s], Default = 0)
.correlation_id_max Integer Attribute The maximum value of CorrelationID in the ID Pool.
This is only required when running an SCP with multiple SIGTRAN apps that are both using same CorrelationID Length (to avoid range conflict).
(Range = 0-[all-9s], Default = [all-9s])
.ori Integer Attribute The SCCP "Own Routing Indicator" for outbound TCAP BEGIN messages.
(Default = 1 if opc and ossn are specified, otherwise 0)
.ossn Positive Integer Attribute The SCCP "Own Sub-System Number" for outbound TCAP BEGIN messages (in Decimal format).
(Range = 1-255)
.sccp_suppress_ossn Integer Attribute Suppress the SCCP OSSN for outbound TCAP BEGIN messages. (Range = 0-1, Default = 0)
.opc Integer Attribute The SCCP "Own Point Code" for outbound TCAP BEGIN messages. (Range = 0-16383 ITU, 0-16777215 ANSI).
.sccp_suppress_opc Integer Attribute Suppress the SCCP OPC for outbound TCAP BEGIN messages. (Range = 0-1, Default = 0)
.ogt_digits Hex String Attribute The SCCP "Own Global Title Digits" for outbound TCAP BEGIN messages.
.ogt_noa Integer Attribute The SCCP "Own Global Title Nature of Address" for outbound TCAP BEGIN messages.
(Range = 0-127)
.ogt_np Integer Attribute The SCCP "Own Global Title Numbering Plan" for outbound TCAP BEGIN messages.
(Range = 0-7)
.ogt_tt Integer Attribute The SCCP "Own Global Title Translation Type" for outbound TCAP BEGIN messages.
(Range = 0-255)
.tcap_pv Integer Attribute Specify 1 to enable the specification of TCAP Protocol Version to all outbound TCAP messages which include an Application Context.
(Values = 0 or 1, Default = 0, do not enable)
.inbound_affinity yes/no/1/0 Attribute When an inbound TCAP_BEGIN is received over a SIGTRAN connection, should we use that same connection as the preferred connection for all outbound TCAP messages on that transaction.
If affinity is disabled then we will independently choose the prerred connection for outbound messages on that transaction according to the configured route selection rules (using priority and loadshare).
This setting does not affect transactions where this SigtranApp sends TCAP BEGIN.
(Values = 0 or 1, Default = 1, inbound affinity is enabled)
.sccp_connection_class Integer Attribute Specify the SCCP Connection Class to use for outbound messages.
This may be further over-ridden on a per-Connection basis.
(Values = 0 or 1, Default = 0)
.sndrcv_buffer Integer Attribute Override the system default SCTP Send/Receive buffers size (in bytes).
The default SCTP buffers will likely be insufficient for sustained load testing or high throughput. Under sustained loads, a value of at least 1048576 bytes (or higher) is recommended.
You will very likely also need to increment the sysctl values for net.core.rmem_max and net.core.wmem_max on your platform.
This may be further over-ridden on a per-Connection basis.
(Default = Use System Socket Defaults)
.sinit_num_ostreams Integer Attribute Override the system default SCTP sinit_num_ostreams.
This may be further over-ridden on a per-Connection basis.
(Default = Use End-Point Default)
.sinit_max_instreams Integer Attribute Override the system default SCTP sinit_max_instreams.
This may be further over-ridden on a per-Connection basis.
(Default = Use End-Point Default)
.sinit_max_attempts Integer Attribute Override the system default SCTP sinit_max_attempts.
This may be further over-ridden on a per-Connection basis.
(Default = Use End-Point Default, typically Max.Init.Retransmit)
.sinit_max_init_timeo Integer Attribute Override the system default SCTP sinit_max_init_timeo.
This may be further over-ridden on a per-Connection basis.
(Default = Use End-Point Default, typically RTO.Max)
.tcap_begin_timer Positive Integer Attribute Default guard timer after sending outbound TCAP_BEGIN or receiving inbound TCAP_BEGIN.
If the SigtranApp does not see any further activity on this transaction within the indicated guard timeout, then it will perform a TCAP-TXNCHECK-REQUEST and (if not checked OK) perform TCAP_ABORT (where possible).
This timer value may be further over-ridden on a per-Handler basis.
(Range = (1..70, Default = 12).
.tcap_continue_timer Positive Integer Attribute Default guard timer after sending outbound TCAP_CONTINUE or receiving inbound TCAP_CONTINUE.
If the SigtranApp does not see any further activity on this transaction within the indicated guard timeout, then it will perform a TCAP-TXNCHECK-REQUEST and (if not checked OK) perform TCAP_ABORT (where possible).
This timer value may be further over-ridden on a per-Handler basis.
(Range = (1..86410, Default = 310).
config Object Element Container for extended configuration for this Application instance.
.connections Array Element Array of connection elements defining SIGTRAN communication paths.
.routes Array Element Array of route elements for selecting connections for outbound delivery.
.handlers Array Element Array of handler elements for selecting the owning Application for inbound TCAP BEGIN messages.

Own Address Parameters

Every SIGTRAN Application instance must have a configured “Own Address”, even if it only uses "Loopback” connections. Specifically, it must have configured at least:

It is possible that a SIGTRAN Application instance may have all three parameters defined, although this would be unusual. If all three parameters are present, then you may wish to explicitly define the "Own Routing Indicator” (ori) parameter.

If the “Own GT Digits” (ogt_digits) are present, then ogt_noa, ogt_np and ogt_tt may also be specified if required.

SIGTRAN Connections

SUA or M3UA Connections

Each SIGTRAN connection is defined by a connection element within the config.connections Array. Multiple connection entries may be defined. The attributes of each connection element are as follows.

Parameter Name Type XML Type Description
name String Attribute [Required] A unique name for this connection.
type String Attribute [Required] The SIGTRAN protocol to use, either sua or m3ua.
mode String Attribute The SCTP socket mode, either connect or listen.
(Default = connect)
sccp_connection_class Integer Attribute Override the default SCCP Connection Class for this connection.
sndrcv_buffer Integer Attribute Override the default SCTP Send/Receive buffers size for this connection.
sinit_num_ostreams Integer Attribute Override the default SCTP INIT sinit_num_ostreams for this connection.
sinit_max_instreams Integer Attribute Override the default SCTP INIT sinit_max_instreams for this connection.
sinit_max_attempts Integer Attribute Override the default SCTP INIT sinit_max_attempts for this connection.
sinit_max_init_timeo Integer Attribute Override the default SCTP INIT sinit_max_init_timeo for this connection.
remote_port Positive Integer Element IPv4 Port Number. Mandatory for SCTP mode = connect.
remote_addresses String Element IPv4 Host Names or A.B.C.D IPv4 Addresses. Mandatory for mode = connect.
May be a single address for the end-point, or a comma-separated multi-homed list.
remote_host String Element An alternative attribute name for remote_addresses.
local_port Positive Integer Element IPv4 Port Number. Mandatory for SCTP mode = listen.
local_addresses String Element IPv4 Host Name or A.B.C.D IPv4 Address. Mandatory for mode = listen.
May be a single address for the end-point, or a comma-separated multi-homed list.
local_host String Element An alternative attribute name for local_addresses.
reconnect_interval Positive Integer Attribute The SCTP-layer reconnection interval in seconds.
(Default = 3)
role String Attribute Our role in the relationship, either as or sg.
This role affects the interpretation and relevance of other connection configuration.
(Default = as)
sg_dpc Integer Attribute Signalling Gateway (next-hop) Destination Point Code.
This is applicable only when role = as.
(Range = 0-16383 ITU, 0-16777215 ANSI).
traffic_mode Enumerated Attribute The Traffic Mode Type to use. Possible values are:
  • 1 = override>
  • 2 = loadshare>
  • 3 = broadcast>
(Default = 2, loadshare)
mtp3_ni Enumerated Attribute The MTP3 Network Indicator to use. Only relevant for m3ua connections. Possible values are:
  • 0 = international
  • 2 = national
(Default = 2, national)
rc Integer Attribute When role = as then this is the Routing Context to use if the far-end SG does not provide it to us. If both configured on the AS and provided by the SG then the two values must agree.
When role = sg then this is the Routing Context to supply to the far-end AS.
concerned_pcs String Attribute This is a comma-separated list of decimal point code values.
Currently these are only supported for m3ua connections.
When role = as then at connection activation time we will send an M3UA DAUD (Destination Audit) request to the far end SG, requesting that we be sent DUNA (Destination Unavailable) and DAVA (Destination Available) SSN Management messages for these point codes.
When role = sg then we will send unsolicited (Destination Unavailable) and DAVA (Destination Available) SSN Management messages for these point codes to the far-end AS.

Loopback Connections

In some testing scenarios, you may wish to connect the Test Application directly to the local Script Application. In such cases you can use configure SIGTRAN with a loopback connection. All messages routed to this SCCP connection will be returned back into the service daemon.

Parameter Name Type XML Type Description
name String Attribute [Required] A unique name for this connection.
type String Attribute [Required] loopback

SIGTRAN Routes

Routing rules define which connection is used to deliver any given message. Each route Object in the config.routes Array is configured as follows.

Parameter Name Type XML Type Description
connection String Attribute [Required] The name of the Connection to deliver matching messages.
global Integer Attribute Specify 1 to indicate that this route can be used for all destinations.
(Default = 0)
pc Integer Attribute A single Point Code to route.
(Range = 0-16383 ITU, 0-16777215 ANSI).
minpc Integer Attribute Start (inclusive) of a Point Code range to route.
(Range = 0-16383 ITU, 0-16777215 ANSI).
maxpc Integer Attribute End (inclusive) of a Point Code range to route.
(Range = 0-16383 ITU, 0-16777215 ANSI).
gt String Attribute A single Global Title to route.
mingt String Attribute Start (inclusive) of a Global Title range to route.
maxgt String Attribute End (inclusive) of a Global Title range to route.
priority Integer Attribute Specify the priority for using this route (if route is active).
Routes with a higher priority number will be preferred.
If multiple suitable routes exist with equal highest priority, then transactions will be loadshared across all available equal highest priority routes.
(Range = 1-5, Default = 1)

Specify exactly one of pc OR minpc/maxpc OR gt OR mingt/maxgt. Point Code ranges are a numeric range. Global Title ranges are checked by string comparison.

You may have any number of routing rules pointing to a connection. In the case of overlapping routing rules, the first matching rule in the list will be used.

SIGTRAN Handlers

Handler rules define which application is used to process an inbound TCAP BEGIN. Each handler Object in the config.handlers Array is configured as follows.

Parameter Name Type XML Type Description
ssn Integer Attribute If specified, the handler applies only to a single destination (local) SSN.
(Default = Match all SSNs)
service_key Integer Attribute If defined, the handler applies only to TCAP_BEGIN containing an Invoke component with operation code = 0 (InitialDP), and whose InitialDPArg contains a ServiceKey with this exact configured integer value.
This service_key match is only valid for a handler which also specifies ssn.
(Default = Match all TCAP_BEGIN, do not check Operation Code or Service Key)
opcode Integer Attribute If defined, the handler applies only to TCAP_BEGIN containing an Invoke component where the operation code matches this exact configured integer value.
This opcode match is only valid for a handler which also specifies ssn.
This opcode match is not valid for a handler which also specifies service_key.
(Default = Match all TCAP_BEGIN, do not check Operation Code)
application String Attribute The name of the application which should process matching TCAP BEGIN operations.
This will normally refer to a ScriptApp instance.

The handlers will be checked in order, and the first matching handler will be used.

Message Handling

In addition to the common Application management messages, the SigtranApp uses the following messages: