An SS7 probe is a physical device to obtain signalling and/or bearer information from a

telecommunications network A telecommunications network is a group of nodes interconnected by telecommunications links that are used to exchange messages between the nodes. The links may use a variety of technologies based on the methodologies of circuit switching, message ...

, such as the

PSTN The public switched telephone network (PSTN) provides infrastructure and services for public telecommunication. The PSTN is the aggregate of the world's circuit-switched telephone networks that are operated by national, regional, or local teleph ...

or a corporate telephone system. The probe passively monitors the E1/ T1 or

SDH SDH may refer to: Science, medicine and technology * Serine dehydratase, an enzyme * L-sorbose 1-dehydrogenase, an enzyme * Succinate dehydrogenase, an enzyme * Shubnikov–de Haas effect * Social Determinants of Health, economic and social condi ...

SONET Synchronous optical networking (SONET) and synchronous digital hierarchy (SDH) are standardized protocols that transfer multiple digital bit streams synchronously over optical fiber using lasers or highly coherent light from light-emitting diode ...

bearer channels, and extracts the signalling information for onward presentation to an application. A passive probe does not affect the network under observation—this is achieved through use of protected monitor points on the network

distribution frame Distribution may refer to: Mathematics *Distribution (mathematics), generalized functions used to formulate solutions of partial differential equations *Probability distribution, the probability of a particular value or value range of a varia ...

Applications

The network application may be lawful interception or a revenue-generating application such as

missed call A missed call is a telephone call that is deliberately terminated by the caller before being answered by its intended recipient, in order to communicate a pre-agreed message. It is a form of one-bit messaging. Missed calls are common in emerg ...

. Probes are also extensively used in

operational support systems Operations support systems (OSS), operational support systems in British usage, or Operation System (OpS) in Nippon Telegraph and Telephone, NTT, are computer systems used by telecommunications service providers to manage their networks (e.g., tele ...

(OSS). Applications served by probes include solutions for inter-carrier billing, revenue loss (by-pass/ phantom traffic and analysis services), fraud prevention, billing, local number portability, quality of service, surveillance ( global call trace), maintenance (

protocol analysis Protocol analysis is a psychological research method that elicits verbal reports from research participants. Protocol analysis is used to study thinking in cognitive psychology (Crutcher, 1994), cognitive science (Simon & Kaplan, 1989), and beha ...

), traffic engineering (link and trunk forecasting), alarming and SS7, Sigtran and IS-41 monitoring. Passive monitoring probes provide a network and switch vendor-independent solution for network applications.

Lawful interception

Lawful interception Lawful interception (LI) refers to the facilities in telecommunications and telephone networks that allow law enforcement agencies with court orders or other legal authorization to selectively wiretap individual subscribers. Most countries require ...

concerns the delivery of calls and data to government approved reception centres. Interception is authorized through a legal framework, such as UK RIPA or US CALEA{{cite web , url = http://www.askcalea.net/calea/ , title = CALEA , access-date = 2008-07-28 , author = US Government , date = 2008-07-28 , url-status = dead , archive-url = https://web.archive.org/web/20080914172940/http://www.askcalea.net/calea/ , archive-date = 2008-09-14 or Russia

SORM The System for Operative Investigative Activities (SORM; russian: Система оперативно-разыскных мероприятий) is the technical specification for lawful interception interfaces of telecommunications and telephone n ...

Technology

SS7 probe technology provides the correct physical interface to the telecommunications network. Opportunities for probing occur in both traditional

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infrastructure as well as in ATM and IP networks. The different characteristics and infrastructure used for these interfaces is reflected in the types of interfaces to be monitored. These range from E1 or T1 2 Mbit/s or 1.5Mbs to

and

STM-x OC-x multiplexes.

Notes

Privacy of telecommunications Telephony signals Electronic test equipment