ETSI ISUP

The ISDN User Part or ISUP is part of the Signaling System #7 which is used to set up telephone calls in Public Switched Telephone Networks. It is specified by the ITU-T as part of the Q.76x series.

When a telephone call is set up from one subscriber to another, many telephone exchanges will be involved, possibly across international boundaries. To allow a call to be set up correctly, where ISUP is supported, a switch will signal call-related information like called or calling party number to the next switch in the network using ISUP messages.

The telephone exchanges are connected via E1 or T1 trunks which transport the speech from the calls. These trunks are divided into 64 kbit/s timeslots, and one timeslot can carry exactly one call. Each timeslot between two switches is uniquely identified by a Circuit Identification Code (CIC) that is included in the ISUP messages. The exchange uses this information along with the received signalling information (especially the Called Party Number) to determine which inbound CICs and outbound CICs should be connected together to provide an end to end speech path.

ITUT ISUP

Different ISUP variants exist. The main specification task is performed by the ITU-T. In Europe ETSI releases its own ISUP specification which is very close to the ITU-T ISUP. The ITU-T and ETSI ISUP are used for international connections and they are the base for national ISUP variants. Most of the countries have their own ISUP variant to cover national specific requirements. ITU-T specification versions:

  • 1984 - ISUP Red Book
  • 1988 - ISUP Blue Book
  • 1991 - ISUP Q.767
  • 1992 - ISUP'92 White Book (segmentation, compatibility, new supplementary services)
  • 1997 - ISUP'97 (new procedures, IN CS1, new supplementary services)

ANSI ISUP

ISUP for the American markets. The American National Standards Institute or ANSI is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organization also coordinates U.S. standards with international standards so that American products can be used worldwide.

Other protocols and interfaces

Protocols:

Interfaces:

ISUP over SIGTRAN

The ISDN User Part or ISUP is part of the Signaling System #7 which is used to set up telephone calls in Public Switched Telephone Networks. It is specified by the ITU-T as part of the Q.76x series.

When a telephone call is set up from one subscriber to another, many telephone exchanges will be involved, possibly across international boundaries. To allow a call to be set up correctly, where ISUP is supported, a switch will signal call-related information like called or calling party number to the next switch in the network using ISUP messages. Each timeslot between two switches is uniquely identified by a Circuit Identification Code (CIC) that is included in the ISUP messages. The exchange uses this information along with the received signalling information (especially the Called Party Number) to determine which inbound CICs and outbound CICs should be connected together to provide an end to end speech path.

In addition to call related information, ISUP is also used to exchange status information for, and permit management of, the available timeslots. In the case of no outbound CIC being available on a particular exchange, a release message is sent back to the preceding switches in the chain so a new route can be tried. SIGTRAN is the name given to an Internet Engineering Task Force (IETF) working group that produced specifications for a family of protocols that provide reliable datagram service and user layer adaptations for SS7 and ISDN communications protocols. SIGTRAN is logically an extension of the SS7 protocol family. It supports the same application and call management paradigms as SS7 but uses an IP transport called Stream Control Transmission Protocol (SCTP) as its underlying transport vehicle. Indeed, the most significant protocol defined by the SIGTRAN group was SCTP, which is used to carry PSTN signaling over IP.

For more information on SIGTRAN, refer to RFC 2719: Architectural Framework for Signaling Transport. RFC 2719 also defines the concept of a Signaling Gateway (SG), which converts CCS messages from SS7 to SIGTRAN. Implemented in a variety of network elements including soft switches, the SG function can provide significant value to existing common channel signaling networks, leveraging investments associated with SS7 and delivering the cost/performance values associated with IP transport.

Most National ISUP variants

ISUP adapted for use in different countries.



Some of our References

Skinny MVNE MTel MVNO iTalk BB MVNO Virgin Mobile MVNO KPN Mobile Weex MVNO Slingshot MVNO Smartspace MVNE Sprint MVNE Entel MVNE, Falabella MVNO
TZMobile MVNO Schiphol IVR BlueSky MVNO IP Payment PCI IVR Ziggo MNO Maz Tiempo MVNO T-Mobile MNO Lemontel Mobile MVNO PrePay solutions PCI IVR Tele2 MNO, MVNO
Sitemap - Disclaimer - Privacy Policy
Copyright© 1984-2017 - Comsys Telecom & Media B.V.

Comsys Connect (Hosted Services)
Livecom (Cloud based Contact Center)