Đang chuẩn bị liên kết để tải về tài liệu:
Scalable voip mobility intedration and deployment- P2

Scalable voip mobility intedration and deployment- P2: The term voice mobility can mean a number of different things to different people. Two words that can be quite trendy by themselves, but stuck together as if forgotten at a bus station long past the last ride of the night, the phrase rings a number of different, and at times discordant, bells. | 8 Chapter 2 2.1.1 The People and Their Devices Phones Phones come in a number of shapes and sizes. Some have the latest features for consumers such as music playing video recording and camera functions global positioning and touch screens with tactile feedback. Some are designed for enterprise users and have large screens with strong email access and integration spreadsheet and document editing capabilities and large storage for use as a computer away from the laptop. Others are simple and rugged meant for use in physically demanding environments where the phones need to withstand a beating. Some have nearly no buttons at all and are even designed for nearly hands-free operation. All in all each phone may seem wildly different from the next. But underneath they are made of the same stuff a microphone to pick up voice a speaker to play it back maybe another speaker for speakerphone operation or to play ringtones so as not to deafen the user who happens to have accidentally hung up on a conversation and is being called back some way to dial some way to see or hear who is calling a battery for mobility and one or more radios to connect back to the network. Within those components the description becomes even more common. There is a digital sampler and a codec engine to convert voice into digital data and back. There is a CPU somewhere orchestrating everything along with memory and some nonvolatile storage. The radios have antennas all folded neatly into the small device. Voice operates the same on every one of these devices and users will become just as irritated by poor audio quality as they will be pleased by good quality. The best voice mobility network is the one that users forget is even there or is anything unique or special. They get out of the way so to speak and let the voice mobility user do her work. 2.1.2 The Separate Channels Signaling and Bearer In the analog telephone days there was only one line per extension. This analog line has to do everything. It