Voice over Internet Protocol (VoIP) is gaining a lot of attention these days, as more companies and individuals switch from standard telephone service to phone service via the Internet. The reason is simple: A single network to carry voice and data is easier to scale, maintain, and administer. As an added bonus, it's also cheaper, because VoIP is free of the endless government regulations and tariffs imposed upon phone companies. VoIP is simply overflowing with hack potential, and VoIP Hacks is the practical guide from O'Reilly that presents these possibilities to you. It provides dozens of hands-on projects for building a VoIP network, showing you how to tweak and customize a multitude of exciting things to get the job done. Along the way, you'll also learn which standards and practices work best for your particular environment. Among the quick and clever solutions showcased in the book are those for: * gauging VoIP readiness on an enterprise network * using SIP, H.3 23, and other signaling specifications * providing low-layer security in a VoIP environment * employing IP hardphones, analog telephone adapters, and softPBX servers * dealing with and avoiding the most common VoIP deployment mistakes In reality, VoIP Hacks contains only a small subset of VoIP knowledge-enough to serve as an introduction to the world of VoIP and teach you how to use it to save money, be more productive, or just impress your friends. If you love to tinker and optimize, this is the one technology, and the one book, you must investigate.

More and more businesses today have their receive phone service through Internet instead of local phone company lines. Many businesses are also using their internal local and wide-area network infrastructure to replace legacy enterprise telephone networks. This migration to a single network carrying voice and data is called convergence, and it's revolutionizing the world of telecommunications by slashing costs and empowering users. The technology of families driving this convergence is called VoIP, or Voice over IP.

VoIP has advanced Internet-based telephony to a viable solution, piquing the interest of companies small and large. The primary reason for migrating to VoIP is cost, as it equalizes the costs of long distance calls, local calls, and e-mails to fractions of a penny per use. But the real enterprise turn-on is how VoIP empowers

businesses to mold and customize telecom and datacom solutions using a single, cohesive networking platform. These business drivers are so compelling that legacy telephony is going the way of the dinosaur, 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 the most common VoIP migration challenges. So if you're a network professional who is migrating from a traditional telephony system to a modern, feature-rich network, this book is a must-have. You'll

discover the strengths 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. Among the challenges discussed andprojects presented:

building a softPBX

configuring IP phones

ensuring quality of service

scalability

standards-compliance

topological considerations

coordinating a complete system ?switchover?

migrating applications like voicemail and directory

services

retro-interfacing to traditional telephony

supporting mobile users

security and survivability

dealing with the challenges of NAT

To help you grasp the core principles at work, "Switching to VoIP" uses a combination of strategy and hands-on "how-to" that introduce VoIP routers and media gateways, various makes of IP telephone equipment, legacy analog phones, IPTables and Linux firewalls, and the Asterisk open source PBX software by Digium.

You'll learn how to build an IP-based or legacy-compatible phone system and voicemail system complete with e-mail integration while becoming familiar with VoIP protocols and devices. "Switching to VoIP" remains vendor-neutral and advocates standards, not brands. Some of the standards explored include:

SIP

H.323, SCCP, and IAX

Voice codecs

802.3af

Type of Service, IP precedence, DiffServ, and RSVP

802.1a/b/g WLAN

If VoIP has your attention, like so many others, then Switching to VoIP will help you build your own system, install it, and begin making calls. It's the only thing left between you and a modern telecom network.