Telecom Resources - Signaling System 7 (SS7)
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Home Telecommunications GSM CDMA 3G SS7 IN Messaging GPRS MVNO (new) Referrals Guestbook	SS7, GSM, CDMA, 3G, IN Information    There are two essential components to all telephone calls. The first, and most obvious, is the actual content—our voices, faxes, modem data, etc. The second isthe information that instructs telephone exchanges to establish connections and route the “content” to an appropriate destination. Telephony signaling is concerned with the creation of standards for the latter to achieve the former. These standards are known as protocols. SS7 or Signaling System Number 7 is simply another set of protocols that describe a means of communication between telephone switches in public telephone networks. They have been created and controlled by various bodies around the world, which leads to some specific local variations, but the principal organization with responsibility for their administration is the International Telecommunications Union or ITU-T. Signalling System Number 7 (SS#7) is the protocol used by the telephone companies for interoffice signalling. In the past, in-band signalling techniques were used on interoffice trunks. This method of signalling used the same physical path for both the call-control signalling and the actual connected call. This method of signalling is inefficient and is rapidly being replaced by out-of-band or common-channel signalling techniques. To understand SS7 we must first understand something of the basic inefficiency of previous signaling methods utilized in the Public Switched Telephone Network (PSTN). Until relatively recently, all telephone connections were managed by a variety of techniques centered on “in band” signaling. A network utilizing common-channel signalling is actually two networks in one:    1. First there is the circuit-switched "user" network which actually carries the user voice and data traffic. It provides a physical path between the source and destination.    2. The second is the signalling network which carries the call control traffic. It is a packet-switched network using a common channel switching protocol. The original common channel interoffice signalling protocols were based on Signalling System Number 6 (SS#6). Today SS#7 is being used in new installations worldwide. SS#7 is the defined interoffice signalling protocol for ISDN. It is also in common use today outside of the ISDN environment. The primary function of SS#7 is to provide call control, remote network management, and maintenance capabilities for the inter- office telephone network. SS#7 performs these functions by exchanging control messages between SS#7 telephone exchanges (signalling points or SPs) and SS#7 signalling transfer points (STPs). The switching offices (SPs) handle the SS#7 control network as well as the user circuit-switched network. Basically, the SS#7 control network tells the switching office which paths to establish over the circuit-switched network. The STPs route SS#7 control packets across the signalling network. A switching office may or may not be an STP. SS7 Resources: IEC: SS7 Tutorial SS7 History (pdf) www.pt.com SS7 Tutorial SS7 Tutorials/Whiltepapers MobileIN SS7 Cisco SS7 Fundamentals SS7 Suite SS7 Protocol Stack NEW ON THIS SITE: MVNO:  is a GSM phenomenon where an operator or company which does not own a licenced  sprectrum and generally with own networking infrastructure. Instead MVNOs resell wireless services under their brand name,  using a  regular telecom operator's network with which they have a business arrangements. Usually they they buy minutes of  use (MOU) from the licenced telecom operator and then resell minutes of usage to their customers of MVNO. Currently MVNOs are  emerging in fast pace in European markets and beginning in USA also. Slowly MVNO phenomenon catching up in Asia and other  parts of the world also. READ MORE HERE
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