In a Cisco VoIP environment, there will be endpoints (phones), a PBX (UCM, Call Manager, or the express versions of these products), and probably voicemail (Cisco Unity). In this chapter, we’ll be building the design shown in Figure 30-1. This IP phone system is designed for the needs of the office of a small but successful consulting company. Any similarities to companies or persons either living or dead are purely coincidental.
There are almost limitless ways in which an IP phone system can be configured. In this chapter, I will show you one way of doing things, but you can likely accomplish the same goal using different methods. As long as the client’s needs are met and there are no vulnerabilities or shortcomings, the way that works is the right way. While there are certainly best practices, when it comes to topics like dial plans, dial peers, and features required, every installation is different.
Figure 30-1. Small-office Cisco CME VoIP deployment
I’m going to build a small-office IP telephony solution using a Cisco 2811 router. Within the router, I have UCM Express, a Cisco Unity Express AIM card (AIM-CUE), and a four-port FXO card to connect to the POTS lines. There is also a PVDM2-48 for CODEC conversion, but it is not needed for the design shown here. For phones, I am using a Cisco7971G, two Cisco 7970Gs, and a Cisco 7960G. The phones connect to ...