The main reason for migration to VoIP is cost, because it equalizes the cost of long distance calls, local calls, and e-mail to a fraction of a penny per use. This driver is very interesting that the telephone business estate will be the way of dinosaurs, yielding to Voice over IP as the dominant enterprise communications paradigm. Developed from real-world experience by a senior developer, O'Reilly's Switching to VoIP provides solutions for VoIP migration challenges the most common. So if you're a professional network that migrate from traditional phone systems to the network, modern feature-rich, this book is a must-have. You will find the strength and weaknesses of circuit-switched and packet-switched networks, how VoIP systems impact network infrastructure, as well as solutions for common challenges involved with IP voice migrations. migrating applications like voicemail and directory of retro-interfacing to traditional phone support security and survivability of mobile users face the challenges of NAT To help you understand the core principles in the workplace, Switching to VoIP uses a combination of strategy and hands-on "how-to" that introduce VoIP routers and media gateways, making a variety of IP telephone equipment, legacy analog phones, and Linux iptables firewall, and source Asterisk PBX software by Digium open. Some of the standards explored include: H.323 SIP, SCCP, and IAX Voice codec 802.3af Type of Service, IP precedence, DiffServ, and RSVP 802.1a/b/g WLAN If VoIP has your attention, like many others, then Switching to VoIP will help you build your own system, install, and start making calls.