Packetized Voice
Packetized voice is the process of converting audio signals into digital packet format, transferring these packets through a packet network, reassembling these packets into their original data form, and then recreating the audio signals.
By the end of 2001, over 5% of international calls from the United States were over the Internet and more than 9.5% of all inter-exchange telecommunications calls were on managed packet switching networks [7]. Packetized voice transmission allows for key features such as dynamic bandwidth allocation and advanced services. To convert to packetized voice, the EO exchange is either replaced or supplemented by a packet switch.
Various protocols such as resource reservation protocol (RSVP) and real time protocol (RTP) have been developed to ensure the quality of service of voice packets that are transmitted through a packet network.
High-Speed Multimedia Services
High-speed multimedia services is the term used to describe the delivery of different types of information such as voice, data or video. Communication systems may separately or simultaneously transfer multimedia information. High-speed multimedia usually refers to image based media such as pictures, animation, or video clips. High-speed multimedia usually requires peak data transfer rates of 1 Mbps or more.
The providing (provisioning) of multimedia services requires communication lines that can have multiple channels and each of these channels may have different quality of service (QoS) levels. As a result, many emerging multimedia services are likely to use ATM.
Fiber Distribution Networks
Fiber distribution networks use optical fiber to distribute communication channels from the PSTN to end customers. There are three key distribution networks: fiber to the neighborhood (FTTN), fiber to the curb (FTTC), and fiber to the home (FTTH).
Figure 1 shows that public telephone networks have growth options. Initially, they are likely to install (FTTN) and use existing copper lines to reach the home. As demand grows for high-speed data communication services, additional fiber may be installed from the node to the curb (FTTC) to replace copper lines. Eventually, to achieve extremely high data rates to the home or business, FTTH or fiber to the basement (FTTB) may be installed.
Soft Switches
Soft switches are interconnection switching systems that can dynamically change its connection data rates and protocols types by software control to provide for voice, data, and video services. Soft switches were developed to replace existing EO switches that have limited interconnection capabilities. Soft switches are packet based and can simulate multiple protocols such as Internet protocol and ATM. This allows for multiple types and simultaneous services to each customer with varying levels of QoS.
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