SIGTRAN is the name, derived from ''signaling transport'', of the former Internet Task Force (I) working group that produced specifications for a family of protocols that provide reliable

datagram A datagram is a basic transfer unit associated with a packet-switched network. Datagrams are typically structured in header and payload sections. Datagrams provide a connectionless communication service across a packet-switched network. The de ...

service and user layer adaptations for Signaling System and

ISDN Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. ...

communications protocols A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any variation of a physical quantity. The protocol defines the rules, syntax, semantics, and synchronization of ...

. The SIGTRAN protocols are an extension of the SS7 protocol family, and they support the same application and call management paradigms as SS7. However, the SIGTRAN protocols use an

Internet Protocol The Internet Protocol (IP) is the network layer communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet. IP ...

(IP) transport called

Stream Control Transmission Protocol The Stream Control Transmission Protocol (SCTP) is a computer networking communications protocol in the transport layer of the Internet protocol suite. Originally intended for Signaling System 7 (SS7) message transport in telecommunication, the ...

(SCTP), instead of TCP or UDP. Indeed, the most significant protocol defined by the SIGTRAN group is SCTP, which is used to carry

PSTN The public switched telephone network (PSTN) is the aggregate of the world's telephone networks that are operated by national, regional, or local telephony operators. It provides infrastructure and services for public telephony. The PSTN consists ...

signaling over IP. The SIGTRAN group was significantly influenced by

telecommunications Telecommunication, often used in its plural form or abbreviated as telecom, is the transmission of information over a distance using electronic means, typically through cables, radio waves, or other communication technologies. These means of ...

engineers intent on using the new protocols for adapting IP networks to the

with special regard to signaling applications. Recently, SCTP is finding applications beyond its original purpose wherever reliable datagram service is desired. SIGTRAN has been published in RFC 2719, under the title ''Framework Architecture for Signaling Transport''. RFC 2719 also defines the concept of a ''

signaling gateway A signaling gateway is a network component responsible for transferring signaling messages (i.e. information related to call establishment, billing, location, short messages, address conversion, and other services) between Common Channel Signal ...

'' (SG), which converts Common Channel Signaling (CCS) messages from SS7 to SIGTRAN. Implemented in a variety of network elements including

softswitch A softswitch (''software switch'') is a call-switching node in a telecommunications network, based not on the specialized switching hardware of the traditional telephone exchange, but implemented in software running on a general-purpose computing ...

es, 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.

SIGTRAN protocols

The SIGTRAN family of protocols includes: *

(SCTP), RFC 2960, RFC 3873, RFC 4166, RFC 4960. *

User Adaptation (IUA), RFC 4233, RFC 5133. * Message Transfer Part 2 (MTP) User Peer-to-Peer Adaptation Layer (M2PA), RFC 4165. * Message Transfer Part 2 User Adaptation Layer (M2UA), RFC 3331. * Message Transfer Part 3 User Adaptation Layer (M3UA), RFC 4666. *

Signalling Connection Control Part {{SS7stack The Signalling Connection Control Part (SCCP) is a network layerITU-T Recommendation Q.1400
pr ...

(SCCP) User Adaptation (SUA), RFC 3868. * V5 User Adaptation (V5UA), RFC 3807. *

DPNSS The Digital Private Network Signalling System (DPNSS) is a network protocol used on digital trunk lines for connecting to PABX. It supports a defined set of inter-networking facilities. DPNSS was originally defined by British Telecom. The specific ...

DASS2 Digital Access Signalling System 2 (DASS2) is an obsolescent protocol defined by British Telecom (BT) for digital links to PSTN based on ISDN. Although still available on request, it has been superseded by ETS 300 102 ("EuroISDN"). DASS2 is an i ...

User Adaption (DUA), RFC 4129 The

provides the

transport protocol Transport (in British English) or transportation (in American English) is the intentional movement of humans, animals, and goods from one location to another. Modes of transport include air, land ( rail and road), water, cable, pipelines, a ...

for SIGTRAN user adaptation layer messages across an IP network. It is described in RFC 3873, RFC 4166 and RFC 4960. ''IUA'' provides an SCTP adaptation layer for the seamless backhaul o
Q.921
user messages and service interface across an IP network. Some users that it supports are Q.931 and

QSIG QSIG is an ISDN based signaling protocol for signaling between private branch exchanges (PBXs) in a private integrated services network (PISN). It makes use of the connection-level Q.931 protocol and the application-level ROSE protocol. ISDN "p ...

. It is specified in RFC 4233. ''V5UA'' provides an SCTP adaptation layer for the seamless backhaul of V5.2 user messages and service interface across an IP network. It is a variation of ''IUA'' and is specified in RFC 3807. ''M2PA'' provides an SCTP adaptation layer for providing an SS7 MTP signaling link over an IP network. It is specified in RFC 4165. The difference between ''M2PA'' and ''M2UA'' is described in section 1.9 of RFC 4165 ''M2UA'' provides an SCTP adaptation layer for the seamless backhaul of MTP Level 2 user messages and service interface across an IP network. It is specified in RFC 3331. ''M3UA'' provides an SCTP adaptation layer for the seamless backhaul or peering of MTP Level 3 user messages and service interface across an IP network. It is specified in RFC 4666. ''SUA'' provides an SCTP adaptation layer for the seamless backhaul or peering of Signalling Connection Control Part user messages and service interface across an IP network. It is specified in RFC 3868.

Scheme

Notes

References

External links

sigtran.org
- Archived SIGTRAN website. *Sergey Puzankov, Dmitry Kurbatov
How to Intercept a Conversation Held on the Other Side of the Planet
2014-05-22, Positive Hack Days.

31c3, CCC,
and Snort
2018-03-31. Computer network organizations Working groups