Purpose
In a multi-channel communications system, Common Channel Signaling (CCS) is signaling in which one channel in each link is used for signaling to control, account for, and manage traffic on all channels of the link. The channel used for common-channel signaling does not carry user information. With CCS, signals are carried by a separate network consisting of Signaling Data Links (SDLs) and Signaling Transfer Points (STPs) to transfer digital signaling messages between exchanges. It is known as CCS because SDLs can carry messages for trunks in many different trunk groups.
The CSP supports the following CCS protocols:
• Integrated Services Digital Network
• Q Signaling (QSIG)
• DASS2/DPNSS
• V5.2 (Local Exchange side)
A telecommunications network served by common channel signaling is composed of a number of switching and processing nodes interconnected by transmission links. To communicate using SS7, each of these nodes must implement the necessary "within node" features of SS7 making that node a signaling point within the SS7 network. In addition, there is a need to interconnect these signaling points such that SS7 signaling data may be conveyed between them. These data links are the signaling links of the SS7 signaling network.
The combination of signaling points and their interconnecting signaling links form the SS7 signaling network.
The main feature of Integrated Services Digital Network (ISDN) is the support of a wide range of service capabilities, including voice and non-voice applications, in the same network by offering end-to-end digital connectivity. A key element of service integration for an ISDN is the provision of a limited set of standard multi-purpose user-network interfaces. These interfaces represent a focal point both for the development of ISDN network components and configurations and for the development of ISDN terminal equipment and applications.
The CSP supports the QSIG/PSS1 global signaling and control standard for Private Integrated Network Exchange (PINX) applications, intended for use in private corporate ISDN networks. QSIG is a Euro-ISDN based protocol for digital Common Channel Signaling (CCS) and is used to build private networks using Virtual Private Networks (VPNs) or leased lines.
Q Signaling (QSIG), an ISDN based protocol, enables signaling between different voice communications platforms and equipment (nodes) in a multi-user environment. It is often referred to as an inter-PBX signaling system. It can also be deployed in a single-user environment.
Internationally, QSIG is also known as Private Signaling System No. 1 (PSS1).
DASS2 is a message-based signaling system following the ISO-based model developed by British Telecom to provide multi-line Integrated Digital Access (IDA) interconnection to the BT network.
Digital Private Network Signaling System is a standard in Britain which enables Private Branch Exchanges (PBXs) from different manufacturers to be tied together with E1 lines and pass calls transparently between each. The calls are made as easily as if the phones were extensions off the same PBX and were simply intercom calls.
V5.2 is a concentration protocol for digital Common Channel Signaling (CCS). It is called a concentration protocol because it can accommodate more subscribers than existing physical ports. The V5.2 protocol is comprised of the LE (Local Exchange) side of the protocol. The V5.2 protocol is used to establish, maintain, and release calls between an LE and an AN.
Excel’s V5.2 products include the hardware and software required to run and manage V5.2 on the Converged Services Platform (CSP). This implementation supports only the Local Exchange (LE) side of V5.2.