ou also need to engage people from different departments and vendors. These all cost money. With a SIP trunk, it's a matter of provisioning enough bandwidth on your broad- band pipe and simply adding new numbers. It can be up in a couple of days, without a truck roll. Summary SIP trunks are the future of UC. Things are moving much faster than we can anticipate. It is inevitable that you will migrate your network from TDM to IP. You will migrate not only to save money, but also to enable other new rich features in the area of UC. You will embrace new things everyday. You can't set up something and sit idle for a long time. We have already seen the migration of digital PBX to IP-PBX. Now, it is time to see the migration of TDM trunk to SIP trunk. In the long run, it can enable you to enjoy a richer communication. In the short term, it is clear that you can save 25 percent to 50 percent of your operating cost by migrating to SIP trunks. Further Reading The following documents and references provide additional information on the topics covered in this chapter. SIPTrunks.org: Using its tool you can instantly compare SIP trunking pricing from multiple SIP trunk providers. http://siptrunks.org. SIP Trunking Quotes: It offers SIP Trunking quotes from different reliable providers in the United States. Services available include local and long distance SIP voice, business VoIP, hosted IP-PBX, T1, IP Centrex, and more. http://siptrunkingquotes.com. VoIP Review: You can find reviews of different kind of residential and business SIP trunk providers. http://www.voipreview.org. This page intentionally left blank Chapter 5 Components of SIP Trunks This chapter covers the following topics: Service provider network components Enterprise network components The term Session Initiation Protocol (SIP) trunk can mean many things, but generally a few important components make up any system that includes SIP trunks. This chapter describes the essential components that make up a SIP trunk solution, from both a service provider (SP) and an