This chapter covers the following topics:
This chapter describes the primary call processing features of Cisco CallManager Express (CME) and shows how you can combine them to produce an extensive set of call handling behaviors. It includes a basic discussion of the advantages of IP telephony for the small office and relates these to the more traditional time-division multiplexing (TDM) or analog-based telephone systems historically used in the small private branch exchange (PBX) and Key System marketplace.
This chapter explains the terminology and Cisco IOS commands (command-line interface [CLI]) used to configure IP phones, extension lines, shared lines, overlays, intercom, paging, call park and pickup, hunt groups, and other forms of call coverage. One of the key perspectives to understanding Cisco CME is that it is built on top of a Cisco IOS router. This means that the same modular feature approach that dominates the general Cisco IOS command-line organization is carried forward into the Cisco CME structure. The result is that individual component features are designed to be as modular and flexible as possible. It also means that it is often possible to combine features to produce some fairly complex operations. Some of these combinations are not obvious from a quick glance at the CLI. This chapter is intended to help you understand and use some of the available flexibility.
The sample configurations in this chapter are presented using the Cisco IOS CLI. Many of the configurations described can also be generated using the web browser graphical user interface (GUI). In both cases, the configurations generated are stored identically in the router's nonvolatile memory in CLI format. The CLI presentation is more compact and easier to grasp than an equivalent series of GUI screen shots. The CLI presentation also shows the integration of some Cisco CME-specific functions with the CLI commands for related but generic Cisco IOS router functions, because the generic Cisco IOS commands usually don't have a GUI equivalent. The CLI format is also convenient for many readers who may already be very familiar with the Cisco IOS CLI. The GUI is more extensively covered in Chapter 13, "Cisco IPC Express General Administration and Initial System Setup," and Chapter 14, "Configuring and Managing Cisco IPC Express Systems."
The objective of this chapter is to give you a broad understanding of the options that Cisco CME provides. It's not meant to be an exhaustive manual on how to configure a Cisco CME system to meet every possible combination of network design circumstances you might encounter. System configuration is covered in Chapter 14. For the more sophisticated configurations, consult the detailed Cisco IOS feature and Cisco CME administration documentation available online at Cisco.com.
The less-complex configurations are generally simple to build, even using the CLI. At the same time, the broad range and component-level adaptability of the Cisco IOS software platform is available if required to deal with the complexity of real-life network situations. Hopefully by reading this chapter, you will at least have a good idea of what you're looking for when you decide to tackle the extensive Cisco IOS, voice over IP (VoIP), and Cisco CME documentation that's available online.
IP Phones and IP Phone Lines