In October 2004, Cisco Systems released Cisco CallManager 4.1(2). CallManager, the heart of the Cisco IP Communications solution, provides administrators a platform by which they can manage their enterprise’s voice communications over the same network on which they manage their enterprise’s data communications. It enables devices that speak dozens of different protocols to communicate together with seeming effortlessness and supports both enterprise and endpoint applications.
We, the writers of this book, have been intimately involved with CallManager since its inception in 1997. And as the years have gone by, we’ve watched as both the capability and the complexity of the product have increased. Features that seemed obvious to us during CallManager development have sometimes proved less than obvious to those who have actually deployed CallManager. Furthermore, although the Cisco CallManager System Administration and Features and Services Guide is very good at telling you how to accomplish specific tasks, it isn’t always as good at telling you why you need to accomplish a specific task, or in providing you with a framework for understanding how different CallManager concepts work together, or the underlying architecture of the product itself.
Therefore, we have tried to distill our knowledge of CallManager into these many hundred pages in the hopes that you will find here what you might not have found elsewhere: a blueprint that reveals order amid the dozens of devices and the hundreds of features that CallManager supports.
This book targets CallManager release 4.1(2), released in October 2004. Most of the material this book presents should apply for future releases as well. Long printing lead times and subsequent 4.1(x) releases might render some of this information out-of-date, but we have tried to protect against that wherever possible by foreseeing those changes.
The first edition of this book was applicable for many releases beyond the target release, and we expect similar performance for this edition. The architectural information presented in this edition should be useful for years to come. Generally, when new features and protocols are added, the existing architecture gets expanded rather than replaced, so the applicability of the information presented here should continue to be useful even as CallManager experiences ongoing major (first digit, such as 5.x) and minor (second digit, such as x.2) revisions.
The authors are interested in your comments and suggestions about this book. Please send feedback to the following address:
This book provides a view of the Cisco IP Communications solution that centers on CallManager. This information helps you put together in your mind the various pieces of CallManager so that you can better understand how to design and implement your own CallManager system. By learning how CallManager processes information, you can configure and troubleshoot your system more effectively.
This book is directed to CallManager system administrators who are responsible for configuring CallManager, integrating it into their networks, and maintaining it. This book is also appropriate for network architects looking to integrate Cisco IP Communications with third-party applications and for people interested in the nuts and bolts of a VoIP solution.
Each chapter provides basic information about the subject matter, followed by more detailed information. Chapter 1 includes a block diagram of CallManager’s internal components. This diagram is subsequently presented in the introduction of each chapter of the book. The CallManager components that are covered in a particular chapter are highlighted in this diagram. Every chapter ends with a summary section that highlights the critical information that the chapter presents.
If you are new to CallManager, you should be able to get a feel for the information just by reading the first few sections of each chapter. Then you can return to read the more detailed sections as your knowledge of the product increases and you find yourself looking for more answers. For the “old-timers” out there who have been working with CallManager since 1997, the deeper you go into the sections, the more rewarded with information you will be.
This book uses the following formatting conventions to convey additional meaning:
Key terms are italicized the first time they are used and defined.
Notes emphasize information of a noteworthy or unusual nature.
Sidebars provide additional information about important or interesting topics.
Tips are handy information bits about the subject.
Cautions provide critical information.
This book is meant to complement the information already available on Cisco.com and in the CallManager documentation. This book does not provide detailed configuration information or step-by-step instructions. The chapters in this book address the following topics:
Chapter 1, “Cisco CallManager Architecture,” provides an overview of VoIP telephony and describes the evolution of CallManager. It describes the hardware and software components that make up Cisco IP Communications and outlines several methods for deploying a Cisco IP Communications solution.
Chapter 2, “Call Routing,” discusses the fundamental building blocks of the CallManager call routing infrastructure and describes how you can apply these building blocks to solve complex routing problems that most enterprises face.
Chapter 3, “Station Devices,” describes the station devices supported by CallManager. It categorizes them by protocol and then subdivides them by device capabilities.
Chapter 4, “Trunk Devices,” details the gateway protocols supported by CallManager, including H.323, Media Gateway Control Protocol (MGCP), QSIG, and Session Initiation Protocol (SIP). It describes how the protocols signal to gateways, to other CallManager clusters, and to gatekeepers where applicable.
Chapter 5, “Media Processing,” discusses allocation and control of media processing resources, such as conference bridges, transcoders, annunciator, and music on hold (MOH) servers. It explains media connection processing and call preservation.
Chapter 6, “Manageability and Monitoring,” describes tools that you can use to make CallManager easier to manage. It explains in some detail the plug-ins and applications that work with CallManager to assist with system monitoring.
Chapter 7, “Call Detail Records,” describes the facilities provided for controlling the generation and storage of call detail records (CDR) and call management records (CMR), and it provides information on how to access, interpret, and use the stored data.
Appendix A, “Feature List,” provides a list of CallManager and Cisco IP Phone features through release 4.1(2).
Appendix B, “Cisco Integrated Solutions,” details Cisco-developed solutions that can be used in conjunction with CallManager or other components in the Cisco IP Communications system.
Appendix C, “Protocol Details,” provides information about call signaling for the following protocols: H.323, SCCP, QSIG, and SIP. It also describes JTAPI packages and provides details on how you can write your own Cisco IP Phone services.
The authors recommend the following sources for more information.
You should be familiar with and regularly using the documentation that is provided with the Cisco IP Communications system to supplement the information in this book.
You can find Cisco IP Communications documentation by searching for a specific product on Cisco.com or by starting at the following link:
http://www.cisco.com/univercd/cc/td/doc/product/ipcvoice.htm
Learn best practices for deploying, maintaining, managing, and monitoring CallManager and related components. Hundreds of best practices are offered in the following areas: centralized call processing deployments, installation, backup and restoration, upgrades and patches, security, system configuration, dial plan, features, IP phones, gateways, tools and applications, services and parameters, directory integration, CDRs, manageability and monitoring, Multilevel Administration (MLA), and Real-Time Monitoring Tool (RTMT). You can examine this book (ISBN: 1-58705-139-7) at your favorite local or online bookseller.
Discover extensive troubleshooting information and troubleshooting methodology. All parts of a Cisco IP Telephony solution are examined, with particularly excellent information about reading traces, the many troubleshooting tools available to you (including a few special ones available for download with the book), voice quality, and gateways. You can examine this book (ISBN: 1-58705-075-7) at your favorite local or online bookseller.
Find instructions and tools for creating custom phone services and directories for Cisco IP Phones in the book Developing Cisco IP Phone Services (ISBN: 1-58705-060-9). You can examine this book at your favorite local or online bookseller.
Enjoy real-world examples and explanations with technical details, design tips, network illustrations, and sample configurations that guide you through the stages of planning a large-scale IP Telephony network, choosing the right architecture and deployment model, implementing, operating, and finally optimizing the deployment. You can examine this book (ISBN: 1-58705-157-5) at your favorite local or online bookseller.