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Dialogic DSI SS7 Stack
SS7 Protocol Stacks for Versatile Service Creation

Dialogic DSI SS7 Stack

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Dialogic DSI SS7 Stack
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Proven Signaling System 7 (SS7) protocol implementations for use within high performance products. Dialogic DSI SS7 Stack supports a wide range of SS7 capabilities to manage signaling traffic between applications and SS7 networks over TDM or IP. Use with DSI SS7 Boards or DSI SIGTRAN Stack to build scalable systems for Prepaid, Roaming, SMS, USSD Services, Location Based Services, Call Control etc.

The DSI Development Package available now includes a set of Java classes providing functionality for use in a Java environment.

SS7 Software

  • SCCP - (Signaling Connection Control Part class 0,1,2) ITU-T recommendations Q.711-Q.714, Q.791 and ANSI T1.112
  • TCAP - (Transaction Capabilities Application Part) ITU-T Q.771-Q.774 and ANSI T1.114
  • INAP, AIN - (Intelligent Networking) ITU CS1, ETSI CS1 & CS2 and GR-1299-CORE AIN
  • IS41, WIN - ANSI/TIA/EIA-41.5-D, Wireless Intelligent Networking (WIN) extensions ANSI/TIA/EIA-751, ANSI/TIA/EIA-764, ANSI/TIA/EIA-771, ANSI/TIA/EIA-826 [Prepaid]
  • CAMEL - CAMEL Application Part specifications v1-v4
  • MAP - (Mobile Application Part) GSM TS 09.02, TS 29.002
  • MTP - (Message Transfer Part) as defined by the ITU-T, ANSI.
  • ISUP - (ISDN User Part) ITU-T Q.761-Q.764, Q.767, ETS 300 356-1, ANSI T1.113, national variants including German ISUP, Japanese TTC ISUP.
  • BICC - (Bearer Independent Call Control) Q.1902.1 – Q1902.5, Q.765.5, Signalling Transport Converter Q.1901

Distributed Signaling Interface (DSI) Protocol Stacks

Dialogic Distributed Signaling Interface (DSI) Protocol Stacks support a range of Signaling System 7 (SS7) and IETF SIGTRAN specifications to provide solid building blocks for the most advanced applications. These signaling protocols have been extended for multiple country-specific and geographic-specific variations, such as the following:

  • American National Standards Institute (ANSI) and Telcordia Technologies (formerly Bell Communications Research; Bellcore*) standards within North America
  • European Telecommunications Standards Institute (ETSI) standard in Europe
  • International Telecommunications Union (ITU) global standard

The Internet Engineering Task Force (IETF) develops and promotes the Signaling Transport (SIGTRAN) protocols that allow the transport of packet-based Public Switched Telephone Network (PSTN) signaling over Internet Protocol (IP) networks. These protocols gain more and more importance as they suitably position customers to participate in the migration to IP networks.

The Dialogic DSI SS7 Stack and Dialogic DSI SIGTRAN Stack are complemented by the DSI run-time environment that coordinates the execution of signaling operations among separate processors in the configuration: the application host computer, the Dialogic Network Interface Boards with protocol acceleration capabilities, and remote signaling servers where messages can be processed without use of host computer cycles. The DSI message handling software transports signaling information between protocol layers or between a protocol layer and an application layer in a totally transparent way, regardless of the physical source and destination of the messages.

The DSI SS7 Stack enables developers to use SS7 for many applications including prepaid calling, Short Message Service (SMS), Location-Based Services (LBS), Intelligent Networking (IN), and many others. The protocol stacks, boards, and servers have been deployed throughout the world, providing signaling in various networks, as well as connections to many switch types. This facilitates the deployment and the portability of Value Added Services (VAS) in circuit switched (PSTN) and Next Generation Networks (IP) at a worldwide level.

The SS7 and SIGTRAN Protocol Stacks

The SS7 and SIGTRAN protocol implementations available from Dialogic are shown in Figure 1 with their relationship to the Open Systems Interconnection Basic Reference Model (OSI Model).

Figure 1. DSI SS7 and SIGTRAN Protocol Stacks
Figure 1. DSI SS7 and SIGTRAN Protocol Stacks

Features and Benefits:

Key Features
APIs address complete message content to enable unrestricted service creation
Common API for SS7 and SIGTRAN protocols to aid migration of services from TDM to IP carrier networks, e.g. MTP3 to M3UA
Support for industry standards as well as many country variations
Distributed execution of protocol layers to facilitate scaling and performance tuning by adding or load-balancing processing components without application changes
Proven track record of deployment

DSI Protocol Stacks are supported for several Solaris, Linux, and Windows operating systems, including:

  • Solaris: Solaris 9, Solaris 10 (64 and 32 bit)
  • Linux: Red Hat 9, RH enterprise server, MontaVista, SUSE, and others 
  • Windows: Windows Server 2008 R2, Windows 7, Windows Vista

Supported SS7 Protocols:

SS7 layers supported in the DSI SS7 Stack are listed in this section along with the industry specifications that they implement. Complete statements of compliance are available by contacting your Dialogic sales representative.

MTP (Message Transfer Part)
MTP transports information from the upper layers (including the user parts and SS7 applications) across the SS7 network and includes the network management procedures to reconfigure message routing in response to network failures.

MTP1 is the physical, electrical, and functional interface to the network. MTP2 handles the delivery of messages between the signaling end points including error detection and correction. MTP1 and MTP2 functions are accomplished by hardware and firmware components of the Dialogic DSI SS7 Boards.

MTP3 distributes signaling messages to the correct user part: ISUP for circuit related messages and SCCP for transaction dialogues and managing traffic on the signaling links. MTP3 can be configured to run on the board or on the application host computer.

DSI MTP Layer complies with these specifications:

  • ITU-T Q.700 through Q.707, Q.781, Q.782, Q.791
  • ITU-T Q.703 Annex A – “Additions for a national option for high speed signaling links”
  • ITU-T Q.704 – MTP Restart
  • ANSI T1.111-1992 Message Transfer Part
  • UK BTNR5146 and PNO-ISC/SPEC/005

ISUP (ISDN User Part)
ISUP is the functional part of the SS7 protocol for call control — the part that specifies the inter-exchange signaling procedures for setting up and tearing down trunk calls between networks.

DSI ISUP Layer complies with these specifications:

  • ITU-T Q730, Q.761 through Q.764, Q.767
  • ETSI ETS 300 356-1
  • ANSI T1.113
  • ISUP GR-394 (Telcordia)
  • JT-Q761 through JT-Q764, JT-Q850 (Japan TTC)
  • YDN 038 (China)
  • SSURF (SPIROU) (France)
  • ACIF G500 (Australia)
  • C2122 Ed. 2 (Belgium)
  • SFS 5779. (Finland)
  • ZZN7 3.0.0 (Germany)
  • HKTA 2202 Issue 02 (Hong Kong)
  • Specifica Tecnica N.763 (Italy)
  • NOM-112-SCTI (Mexico)
  • 8211-A335 ISDN-ISDN and 82211-A325 ISDN-PLMN (GSM) (Sweden)
  • PNO-ISC/SPEC/007 2.2 (UK)

BICC (Bearer Independent Call Control)
BICC is a new generation of call control protocol — it differs from ISUP by operating independently of bearer and signaling message transport technologies. BICC functionality is included in the ISUP binary file but is enabled by a separate license.

DSI BICC Layer complies with these specifications:

  • ITU-T Q.1901, Q1902.1-Q.1902.5

TUP (Telephony User Part)
TUP is a predecessor to ISUP; this protocol is primarily used in China.

DSI TUP Layer complies with these specifications:

  • ITU-T Q.721 through Q.724
  • GF001-9001 (China)
  • SSUTR2 Specification V11-T 1988 (France)

SCCP (Signaling Connection Control Part)
SCCP provides address resolution services, such as global title, for locating services within the network for both connectionless and connection-oriented operation.

DSI SCCP Layer complies with these specifications:

  • ITU-T Q.711 through Q.714
    — Connectionless – Class 0 and 1
    — Connection-Oriented – Class 2
  • ETSI ETS 300 589
  • ANSI T1.112

TCAP (Transaction Capabilities Application Part)
TCAP is used for transporting transaction-oriented data across the SS7 network. It implements standard Remote Operation Service Element (ROSE) services for applications such as GSM-MAP and IS-41. These applications provide IN services such as Home Location Register (HLR) or Short Message Service (SMS).

DSI TCAP Layer complies with these specifications:

  • ITU-T Q.771 through Q.774, X.680, X.690
  • ETSI ETS 300 134, ETS 300 287
  • ANSI T1.114

MAP (Mobile Application Part)
MAP addresses the registration of roamers and the intersystem hand-off procedure in Global System for Mobile Communications (GSM) wireless mobile telephony.

DSI MAP implements a number of services, including Short Message Service (SMS), Unstructured Supplementary Service Data (USSD), supplementary services, location service management services, IMEI management services, and Any Time Information handling services.

DSI MAP Layer complies with these specifications:

  • GSM 09.02 (TS 100 974)
  • GSM 29.002

INAP (Intelligent Network Application Part)
INAP enables network services and customer applications within the distributed environment of the Intelligent Network (IN) to deliver easily programmable services on a per customer basis, such as follow-me, televoting, prepaid, and credit card calls.

DSI INAP Layer complies with these specifications:

  • ETSI ETS 300 374-1 – ETSI CS1
  • EN 301 140-1 – ETSI CS2
  • ITU-T Q.1218 CS-1R

CAP (CAMEL Application Part)
CAP provides an extension to enable implementation of IN-based services in GSM/3G mobile networks, such as prepaid roaming, fraud control, special numbers, and closed user groups.

DSI CAP Layer complies with these specifications:

  • GSM 09.78 (ETSI TS101 046 - V5.6.0) CAMEL Phase 1
  • GSM 09.78 (ETSI TS101 046 - V6.3.0) CAMEL Phase 2
  • GSM 09.78 (ETSI TS129 078 - V4.6.0) CAMEL Phase 3
  • 3GPP TS 29.078 V7.3.0 R7, 3GPP TS 29.278 V7.0.0 R7 (IMS) CAMEL Phase 4

AIN (Advanced Intelligent Network)
AIN is a telephone network architecture that separates service logic from switching equipment, allowing new services to be added without having to redesign switches to support new services. Developed by Bell Communications Research, AIN is recognized as an industry standard in North America.

DSI AIN Layer supports selected operations of this specification:

  • GR-1299-Core

IS-41 (Electronic Industries Association/Telecommunications Industry Association Interim Standards-41)
ANSI-41 (IS-41) is a standard for identifying and authenticating users, and routing calls on mobile phone networks. The standard also defines how users are identified and calls are routed when roaming across different networks. ANSI-41 is the standard used by AMPS (analog), IS-136 (TDMA), and CDMA networks. GSM and WCDMA networks use a different standard, known as MAP.

WIN (Wireless Intelligent Network, including IS-826-Prepaid)
WIN is a concept intended to drive Intelligent Network (IN) capabilities, based on Interim Standard (IS)-41, into wireless networks. IS-41 is a standard currently being embraced by wireless providers because it facilitates roaming. Basing WIN standards on this protocol enables evolution to an IN without making current network infrastructure obsolete. DSI IS-41 supports full access to the Short Message Service (SMS) operations and associated parameters.

DSI IS-41 Layer complies with these specifications:

  • ANSI/TIA/EIA-41.5-D
  • ANSI/TIA/EIA/771
  • ANSI/TIA/EIA/826


Technical Specifications
DSI SS7 Stack DSI SS7 Layers can be executed in host memory or on Dialogic DSI SS7HD Network Interface Boards or Dialogic DSI SPCI Network Interface Boards with the purchase of an appropriate license.
  • Links per link set: 16
  • Link sets: 64
  • Destination point codes: 128
  • Routes: 4,096
  • Routes from single point code: 500
  • MTP Restart: Yes
  • 8-bit SLS rotation: Yes
SCCP Global Title Translation entries: 256
  • Point codes: 128
  • Circuits: 64,000
TCAP, INAP, MAP, IS-41 Simultaneous dialogues per process: 64,000


Download the Dialogic DSI Protocol Stacks Datasheet (.PDF)


Dialogic Products
Dialogic DSI SS7 Stack
Dialogic MTP3 Protocol Layer host license
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Dialogic ISUP Protocol Layer host license
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Dialogic TUP Protocol Layer host license
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Dialogic BICC Protocol Layer host license
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Dialogic SCCP Connectionless Protocol Layer host license
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Dialogic SCCP Connection Oriented Host Protocol Layer host license
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Dialogic TCAP Protocol Layer host license
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Dialogic MAP Protocol Layer host license
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Dialogic IS-41 Protocol Layer host license
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Dialogic INAP Protocol Layer host license
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