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 and projects 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.
Foreword Preface 1. Voice and Data: Two Separate Worlds? The PSTN Key Systems and PBXs Limits of Traditional Telephony VoIP in the Home VoIP in Business VoIP's Changing Reputation Key Issues: Voice and Data: Two Separate Worlds 2. Voice over Data: Many Conversations, One Network VoIP or IP Telephony Distributed Versus Mainframe Key Issues: Voice over Data: Many Conversations, One Network 3. Linux as a PBX Free Telephony Software Installing Legacy Interface Cards Compiling and Installing Asterisk Monitoring Asterisk Key Issues: Linux as a PBX 4. Circuit-Switched Telephony Regulation and Organization of the PSTN Components of the PSTN Customer Premises Equipment Time Division Multiplexing Point-to-Point Trunking Legacy Endpoints Dial-Plan and PBX Design Key Issues: Circuit-Switched Telephony 5. Enterprise Telephony Applications Application Terminology Basic Call Handling Administrative Applications Messaging Applications Advanced Call-Handling Applications CTI Applications Key Issues: Telephony Applications 6. Replacing the Voice Circuit with VoIP The "Dumb" Transport Voice Channels Key Issues: Replacing the Voice Circuit with VoIP 7. Replacing Call Signaling with VoIP VoIP Signaling Protocols H.323 SIP IAX MGCP Cisco SCCP Heterogeneous Signaling Key Issues: Replacing Call Signaling with VoIP 8. VoIP Readiness Assessing VoIP Readiness Business Environment Network Environment Implementation Plan Key Issues: VoIP Readiness 9. Quality of Service QoS Past and Present Latency, Packet Loss, and Jitter CoS 802.1q VLAN Quality of Service Residential QoS Voice QoS on Windows Best Practices for Quality of Service Key Issues: Quality of Service 10. Security and Monitoring Security in Traditional Telephony Security for IP Telephony Access Control Software Maintenance and Hardening Intrusion Prevention and Monitoring Key Issues: Security and Monitoring 11. Troubleshooting Tools VoIP Troubleshooting Tools The Three Things You'll Troubleshoot SIP Packet Inspection Interoperability When, Not if, You Have Problems- Simulating Media Loads Key Issues: Troubleshooting Tools 12. PSTN Trunks Dial-Tone Trunks Routing PSTN Calls at Connect Points Timing Trunk Transitions Key Issues: PSTN Trunks 13. Network Infrastructure for VoIP Legacy Trunks VoIP Trunks WAN Design Disaster Survivability Metro-Area Links Firewall Issues Peer-by-Peer Codec Selection Key Issues: Network Infrastructure for VoIP 14. Traditional Apps on the Converged Network Fax and Modems Fire and Burglary Systems Surveillance Systems and Videoconferencing Voice Mail and IVR Emergency Dispatch/911 Key Issues: Traditional Apps on the Converged Network 15. What Can Go Wrong? Common Problem Situations Key Issues: What Can Go Wrong? 16. VoIP Vendors and Services Softphones and Instant Messaging Software Skype Other Desktop Telephony Software Developer Tools and SoftPBX Systems VoIP Service Providers Telephony Hardware Vendors 17. Asterisk Reference How Asterisk Is Supported Asterisk's Configuration Files Asterisk Dial-Plan Asterisk Channels The Asterisk CLI Integrating Asterisk with Other Software Key Issues: Asterisk Reference A. SIP Methods and Responses B. AGI Commands C. Asterisk Manager Socket API Syntax Glossary Index
