The evolutionary development of telecommunications networks towards the next generation, the existence of a competitive, multi-operator environment and the need to provide coverage for rural and suburban areas was imposing two basic requirements on modern digital telephone exchanges in past decades: the need to provide full functionality in a scalable and economical way as well as the provision of a structural base for the evolution towards broadband and NGN functionality. The SI2000 TDM product family is a system that has fulfilled both of these requirements for more than 30 years.
The SI2000 TDM system offers telecommunications services to subscribers with analog and Euro-ISDN terminals. It can be connected to various types of networks, analog, digital and ISDN digital, which can be private, public or dedicated networks.
The SI2000 family has been generically developed as a dual-role system: as a telephone exchange for carrier-class networks, with a full public-exchange feature set, including SSN7 signaling, charging and carrier-class system reliability and availability; and as an exchange for enterprise networks with a full PBX feature set, terminals and solutions.
The architecture of the SI2000 telephone exchange is based on the structural model of a two-layer telecommunications network in accordance with the ITU-T definition, with different programmable nodes.
The SI2000 Switch Nodes (SI2000 SNs) represent the switching layer of the network, where the SI2000 Access Nodes (ANs) represent the access layer of the network. The interchange of information between these two layers is performed using the standardized V 5.2 access protocol.
In parallel with these two nodes, the Management Node takes the position of the management layer of the telecommunications network model.
The three basic types of HW platform in the SI2000 telephone exchanges are:
The MLC platform, with the possibility to connect subscribers, analog trunks and E1 network interfaces. The MLC platform can be loaded with an access SW package or with a stand-alone exchange SW package.
The MCA platform, for bigger configurations of exchanges with E1 network interfaces only. This platform can be loaded with the switch-node SW package.
The standard Windows PC platform for the Management Node.
The SI2000 Switch Node (SI2000 SN) is used as a call-control (switching) device for exchanges with larger capacities.
This node is based on the MCA platform, hosting the switch-node program package. The MCA uses E1 interfaces to the network as well as to connect the access layer of the system composed of a number of Access Nodes and the access devices of other vendors. They are controlled via the standard access protocol (V5.2) by a SI2000 Switch Node, which performs all call-control and call-control-related
functionality, as well as networking.
The SI2000 Access Node (SI2000 AN) performs concentration and access functionality, interfacing subscribers with the switching part of the exchange. The host for the access SW package is the MLC platform, with up to 704 subscriber lines and up to 16 E1 interfaces to the Switch Node. The functions of the SI2000 Access Node are controlled by the Switch Node, using theV5.2 access protocol.
The Switch Access Node (SI2000 SAN) simultaneously performs the functionalities of switching and access on the same platform. The host for the Switch Access Node is the MLC platform, loaded with the stand-alone exchange SW package. As it performs the full functionality of the Switch Node, it can also control a number of Access Nodes, using the V5.2 protocol. This type of node is suitable for the lower-capacity range of SI2000 exchanges.