This chapter provided an architectural overview of the two main Cisco IPC Express components: Cisco CME, the router-based call processing engine, and Cisco UE, the AA and voice mail applications engine.
The Cisco CME architecture was discussed within the larger scope of Cisco IOS-based voice services. This chapter covered how Cisco CME features and services fit within, and reuse, fundamental Cisco IOS voice infrastructure, such as dial peers and PSTN trunk interfaces. It also discussed how the Cisco CME software handles the different VoIP protocols, including SCCP, H.323, and SIP. This included considerations such as firewalls and NAT.
Cisco UE hardware is a module that fits within the router. You learned how this hardware communicates with the router hardware and software. The Cisco UE applications environment is based on Linux. The software components, structure, and interactions between subsystems also were explained.
All this information provides a solid understanding for the fundamental components and functions of a Cisco IPC Express system. The chapters in Part II of this book describe in much more detail exactly what the Cisco IPC Express features are, how they can work in your business, and how you can configure and manage the system to your best advantage. Part III draws on this architectural information, because a fundamental understanding of the system components is necessary to troubleshoot the system.