دانلود کتاب Switching to VoIP

More and more businesses today are having their phoneservice delivered to them through their Internet connectioninstead of the local phone company. This method ofreceiving service over the Internet is known as VoIP (anacronym for "Voice Over IP"). VoIP has become a viablesolution and has piqued the interest of companies small andlarge. The primary reason for migrating to VoIP is cost, asit limits long-distance charges to the nominal cost ofemail-instead of the normal toll charges levied bytraditional phone companies.Developed from real-world experience by a senior developer,O'Reilly's Switching to VoIP provides solutions for the mostcommon VoIP migration challenges. So if you're a networkprofessional who is migrating from a traditional telephonysystem to a modern, feature-rich network, this book is amust-have. You'll discover the difference betweencircuit-switched and packet-switched networks, howpacket-switched voice systems impact network infrastructure,as well as solutions for common challenges involved with IPvoice migrations. Among the challenges discussed:user-technology cohesivenessquality of servicescalabilitytopological considerationsapplicationsretro-interfacing to traditional telephonyTo help you better grasp the core principles at work,Switching to VoIP uses a combination of strategy and"how-to" using Cisco internetworking devices, various makesof IP telephone equipment, and the Asterisk open source PBXsoftware by Digium.If VoIP has got your attention, like so many others, thenSwitching to VoIP will help you build your own system,install it, and begin making calls. It's the only thing leftbetween you and a more affordablecorporate phone bill.