Internet Telephony Service Provider using SIP Protocol.

Although Voice over IP (VoIP) also known as IP Telephony (IPT) has been in existence for many years, it has only recently begun to take off as a viable alternative to traditional public switched telephone networks (PSTN). Interest and acceptance has been driven by the attractive cost efficiencies that organizations can achieve by leveraging a single IP network to support both data and voice over their Internet or intranet. The thesis explains the fundamentals of a VoIP Service Provider (based on SIP protocol), focusing on the functions and components that make a VoIP solution. Additional requirements for providing VoIP solution in organizational environment or as a business company, offering services to others. The thesis will answer the following questions: what is required for an organization or a company to deploy VoIP? What makes a VoIP system and how can one take advantage of it? Once a general understanding of VoIP is achieved, the 'Service Providers ' are better prepared to tackle the more complex issues in the Internet protocol that go into deploying a secure, reliable and high performance VoIP network. During the thesis work, I have created a package known as “ITSP-SIP ” which aims at easy setup of VoIP covering the basic services. The package will be an open source, ongoing project hosted by IMIT-KTH