Voice Application
An enterprise can build a voice communication system over the IP network, reducing operating expenses (OPEX).
The AR can function as the private branch exchange (PBX) or access gateway (AG) to meet different service requirements.
AR Used as the PBX
A PBX can connect to the Public Switched Telephone Network (PSTN). A traditional PBX is a voice program control switch of an enterprise and provides exchange between phones inside an enterprise or between an enterprise and the PSTN. It implements unified management of incoming and outgoing calls, and integrates functions of phones, fax machines, and modems. As communication technologies develop, the traditional PBX lacks of support for integration with computer telecommunication and VoIP technologies, and openness and standardization. In addition, the communication cost is high. IP PBXs are used to prevent the preceding problems. They integrate voice communication into enterprise data networks so that an integrated voice and data network is established to connect offices and employees around the world.
The AR can function as an IP PBX or a traditional PBX. It can also function as the integrated voice platform to provide specialized voice services.
The AR is the core switching gateway that integrates functions such as number management, service control, and media conversion. It provides open interfaces to connect to traditional PBXs and access gateways to allow flexible networking.
SIP (SIP IP, SIP PRA, SIP AT0)
PRA
QSIG
R2
AT0
BRA
H.323
AR Used as the AG
An AG connects the PSTN to the IP multimedia system (IMS). It can implement conversion between analog and digital signals.
The traditional PSTN uses line switching technology and exclusive lines, and faces problems such as low resource use efficiency and high costs of inter-area communication. As VoIP develops, the IP bearer network solves the preceding problems. The traditional PSTN has been developing for many years and there are many existing devices on the traditional PSTN. Replacing the traditional PSTN with the IP network requires a high cost. Using IP-based AGs can implement integration of the traditional PSTN and data network and smooth evolution of network reconstruction.
The AR can function as the AG and use SIP to connect to the IMS or NGN through the IP bearer network or use H.248 to connect to the MGC. The AGs in the preceding two scenarios are called SIP AG and H.248 AG, respectively.
