IP Telephony Networks and Components

Voice over IP Technology IP/PSTN Gateway   History The Hybrid Service Platforms group has been working on IP Telephony Technology since 1995. Our main areas of interest are Internet telephony and telephony-based applications. The group delivered its first product - IBM Internet Connection Phone (known as ICPhone), an Internet Phone, built on technologies from the Audio\Video group. IP Telephony was identified by HRL as an emerging technology with very vast opportunities, as early as 1995. The ICPhone used proprietary protocols, since a standard did not exist at the time, and we developed a global directory based on Light Directory Access Protocol (LDAP) which has since became a standard. This directory has been used by end users on one of the IGN/Advantis servers without any support since 1996. At the end of 1996, the ITU H.323 standard was accepted by the IP Telephony development community. The Haifa Research Lab, in cooperation with Zurich Research Lab, moved all related activities, such as Internet Phone clients as well as IP/PSTN Gateways and Gatekeepers, to this standard. Voice over IP Technology To achieve high quality voice over IP, several audio technologies were developed in HRL and integrated within HRL IP Telephony components. Below are some of these components: GSM and G.723.1 codecs Echo Cancellation Echo Suppression Voice Activity Detection Silence Suppression Automatic Gain Control Comfort Noise Generation Jitter Control Low Latency Packet Trunking DTMF Detection, Generation and Transfer within RTP packets Simultaneous Voice and Data Protocol (SDP) over PPP   Current Activities IP/PSTN Gateway Haifa Research Lab developed a prototype-based IP/PSTN Gateway during 1997, and a product-based IP/PSTN Scaleable Gateway during 1998. The IP/PSTN Scaleable Gateway is a PRPQ with Telecommunication and Media ISU. The gateway is based on the DirectTalk (DT/6000) product and on the Multi Service Platform (MSP/6000) product. The main features of the gateway are as follows: Service creation environment based on DirectTalk programmability tools providing high level programming as well as APIs to create new services. 1xT1/E1 to 4xT1/E1 ports in the first version. Both GSM and G.723.1 are deployed on the DSP (IBM SPN256 card). All audio technology features as listed above. Packet trunking which gains up to 70% on bandwidth traffic as well as TCP/UDP I/O overhead. The IP/PSTN Scaleable Gateway was developed using distributed architecture concepts and function decomposition concepts, i.e. all its components communicate via message on sockets preceding even new emerging standards, such as MGCP. Related links: Call Center Solutions