SS7 Stack

The SS7 Stack object is created under the SS7 Signaling Object. Right Click on the SS7 Signaling object and select New SS7 Stack. Once this object is configured, an SS7 stack will be created on the 2020 IMG. See below for more information.

 

ClientView Pane

IMG EMS > Logical IMG > IMG Name > SS7 > SS7 Stack

SC_SS7_Stack.png

 

Maximum Objects

Four SS7 Stacks per SS7 Signaling object.

 

Related Topics and Dependencies

Configuring SS7

SS7 Signaling

SS7 Link Set

 

Field Descriptions

Stack ID

This Stack ID field automatically populates the SS7 stack being configured with the next available ID. ID's range from 0-3 since a maximum of four SS7 stacks are allowed on each Physical 2020 IMG Node. To modify the Stack ID, click in the Stack ID field and select a different Stack ID from drop down menu.

 

SS7 Variant

The 2020 IMG supports creating custom SS7 variants through the use of Programmable Protocol Language (PPL) or importing custom variants. Any custom SS7 variants created will be displayed in the drop down menu of the SS7 Variant field. When a custom SS7 Variant is created it is created from a Base Variant such as ANSI 97, ITU97, ETSI V1, etc. When populating the SS7 Variant field with a custom SS7 Variant, the field just below labeled ISUP will automatically get populated with the base variant from the custom variant created. See Importing/Exporting Variants and Signaling Variant for more information on custom variants.

Note: Once a custom variant is assigned to an SS7 stack, the custom variant entries cannot be modified or deleted. The SS7 variant must be de-selected from the SS7 stack or the stack may need to be deleted before any entries can be modified.

 

ISUP

If Base Only (Default) is selected in the SS7 Variant field above, the ISUP field will have a drop down menu with all SS7 Variants the 2020 IMG supports. Select the variant from drop down menu. Variants are displayed in table below along with their point code format. If a custom variant is created, this field will default to the ISUP variant configured in the custom variant.

 

Variant:

Point Code Format:

ANSI 97:

8-8-8

ANSI 95

8-8-8

ANSI 92

3-8-3

ITU 97

3-8-3

ITU 93

3-8-3

CCITT 88

3-8-3

ETSI V1

3-8-3

ETSI V2

3-8-3

ETSI V3

3-8-3

China

8-8-8

JT-ISUP

7-4-5

 

OPC (Originating Point Code)

MTP Layer 3 provides the message routing and failure handling capabilities for the message transport. Each SS7 stack is identified within a network using an SS7 Point Code. This field specifies the originating point code value of the SS7 stack. Point codes are expressed in dotted decimal format. See Point Code Format in table above. To enter a point code, click in the OPC and enter the values separated by decimals. The 2020 IMG Web GUI has error checking and if the Point Code being entered does not satisfy that variant then the incorrect box will get a red shading around it signifying the value entered is incorrect and a max value error box will appear. See screen capture below.

SC_PointCode_ITU.png

 

MTP Pause

When the 2020 IMG receives a TFP (Transfer Prohibit) message from an endpoint indicating that a Destination Point Code is not allowing traffic to pass, the MTP3 layer sends the MTP Pause primitive to the SS7 Stack informing the stack that the Destination cannot accept any traffic. At this point the 2020 IMG will no longer send any messages to that destination point code (DPC). Once the destination is available the endpoint sends a TFA (Transfer Allowed) message indicating that it is available. At this point, an MTP Resume primitive is sent to the SS7 stack. What the 2020 IMG does with this information is configured in this field.

Immediate (Default) - Immediate is the default. If the 2020 IMG stack receives an MTP-Pause primitive the 2020 IMG will immediately process the primitive and take all CICs going to that destination Out of Service immediately.

Delayed - When Delayed is selected and the 2020 IMG stack receives the MTP-Pause primitive but the processing of the message will be delayed. The amount of time the processing of the MTP-Pause primitive will be delayed is set in the SS7 Variant Entry object. Within the SS7 Variant Entry Object there is a field labeled PPL Component Id. Select ISUP SPRC in the PPL Component Id field and select PPL Timers in the PPL Entity type field. At this point the PPL Timer Value can be set. See Variant Entry.

 

Cause Location

The REL message indicates that a circuit is being released. This message can be sent in either direction and contains a mandatory Cause Indicator Parameter that indicates why a circuit was released. Within the Cause Indicator is the location field. The location field describes what part of the network was the reason the REL message was issued. The Cause Location field in the SS7 Stack object has a drop down menu containing the values below. The value selected will be populated in the location field of the Cause Indicator Parameter when a call is released.

User (default) - Message Generated by User

Local private network - Message generated by private network serving the local user

Local public network - Message generated by public network serving the local user

Transit network - Message generated by transit network

Remote public network - Message generated by public network serving the remote user

Remote private network - Message generated by private network serving the remote user

Local Interface - Message Generated by local user

International network - Message generated by international network

Network Beyond Interworking Point - Message generated by network beyond inter-working point.

Note: Under the ISUP Group object there is an object labeled Location Override where the above values can be overridden. For more information, see Location Override link

 

Exchange Type

Type B (Default) - The 2020 IMG sends a GRS/RSC at start-up. The 2020 IMG waits for a remote GRA/RLC before bringing the CICs in service.

Type A - The 2020 IMG does not send any messages at start-up, but responds to a GRS with a GRA, or an RSC with an RLC.

 

Message Compatibility Pass On

This parameter provides instructions to an exchange processing an ISUP message that the message is unrecognized and it does not understand the message. See selections below.

On (Default) - When receiving an incompatible or unrecognized ISUP message, pass it on the outgoing leg.

Off - When receiving an incompatible or unrecognized ISUP message, DO NOT pass it on to the outgoing leg.

Note: This sets the Message Compatibility Pass On parameter in the SS7 stack. This parameter can be configured for each ISUP group also. See ISUP Group-ANSI or ISUP Group ITU link.

 

Network Indicator

The network indicator is part of the ISUP Service Information Octet (SIO). In MTP (Level 3) the network indicator specifies the type of message (National/International) and is often used for routing to a national or international network. The spare values are often used for testing and for temporary use during Point Code conversions.

National (Default) - Used for ANSI ISUP Variants.
International - Used for non-ANSI ISUP Variants.
01 - Spare - Often used for testing and for temporary use during Point Code conversions
03 - Spare - Often used for testing and for temporary use during Point Code conversions

 

Suppress UCIC's

When a message is received with a CIC that is not defined at the receiving node, an Unequipped Circuit Code (UCIC) message is sent in response. The message field contains the unidentified code. The Suppress UCIC's (Unequipped Circuit Identification Code) field controls the transmitting of UCIC's. By default, the Suppress UCIC's field is disabled. This field has a drop down menu allowing field to be modified.

Disabled (Default) - Allow UCIC messaging to be sent when CIC receiving the messaging is Unequipped or not provisioned for use.

Enabled -  Do not allow UCIC messaging to be sent when CIC receiving the messaging is Unequipped or not provisioned for use.

 

CFN Status

The CFN or Confusion Message is sent in response to any message (other than a confusion message) to indicate that all or part of a received message was unrecognized. The receiving entity does not know how to handle the received message so it transmits the CFN message instead.

Enabled (default) - If 2020 IMG receives a message that is not recognized, 2020 IMG will respond and transmit a CFN (Confusion Message) back to the originator.

Disabled - If 2020 IMG receives a message that is not recognized, 2020 IMG will not respond with a CFN (Confusion Message).

Note: This only applies to ISUP messages.

 

 

A/B Plane Bit Insertion and Validation

Used when configuring JTISUP

Disabled (Default)

Enabled

 

SCCP

SCCP is the transport layer and routing mechanism for TCAP messages. Enable SCCP on the SS7 stack if TCAP messaging is to be used. Select from drop down menu one of the following selections.

Disabled (Default) - SCCP Protocol is disabled in the SS7 stack.

ANSI - Enable SCCP Protocol for use with ANSI standards

ITU - Enable SCCP Protocol for use with ITU standards

 

TCAP

Transaction Capabilities Application Part (TCAP), a protocol in the SS7 protocol suite, enables the deployment of advanced intelligent network services by supporting non-circuit related information exchange between signaling points using the Signalling Connection Control Part (SCCP) connection less service. TCAP also supports remote control - ability to invoke features in another remote network switch. TCAP is used on the 2020 IMG for services such as Message Waiting Indicator and TCAP CNAM Database Queries.

Disabled (Default) - TCAP Protocol is disabled in the SS7 stack.

ANSI - Enable TCAP Protocol for use with ANSI standards

ITU - Enable TCAP Protocol for use with ITU standards

 

M3UA Service Mode

Disabled (Default) - M3UA signaling is disabled. Stacks configured with this field disabled cannot be used in M3UA configuration

Signaling Gateway (SG) Mode - The stack being created will have M3UA Service set to Signaling Gateway mode. Signaling Gateway mode can be configured on up to (4) stacks total per Logical 2020 IMG Group. Refer to the Sigtran/M3UA topic for more information. When the Signaling Gateway Mode is selected, either SCCP, TCAP, or both will need to be configured from the SCCP and TCAP fields explained above.

Application Server (AS) Mode - The stack being created will have M3UA Service set to Application Server mode. Application Server mode can be configured on up to (4) stacks total per Logical 2020 IMG Group. See Sigtran/M3UA topic. When the Application Server Mode is selected, either SCCP, TCAP, or both will need to be configured from the SCCP and TCAP fields explained above.

Note: Up to (4) stacks can be created per 2020 IMG using the M3UA protocol. There is no limitation to how many of each type of stack that can be created. For example, on one physical 2020 IMG node, four stacks can be created. The stacks could be all Signaling Gateway Mode stacks, all Application Server Mode stacks, or a mix of both.