Mobile IP Technology and Applications

Stefan Raab and Madhavi W. Chandra

312 pages

US$55.00

Cisco Press 2005

ISBN: 1-587-05132-X

Mobility in communication has become a reality—or has it? While mobile voice communication is a commodity today, this is far from true for data communication. Although wireless Internet access with smart phones, PDAs, and even laptops (at popular hot spots) has spread widely, this doesn't create true mobility for end users. True mobility requires more than a wireless connection wherever and whenever needed. Not only must the physical and data layers support handovers and roaming between cells and various types of wireless networks, but networking protocols must support moves between subnets and networks seamlessly without losing the connection. These protocols must also support the running applications without hiccups. This will mean the real convergence of desktop computing and cellular communications. In Mobile IP Technology and Applications, Stefan Raab and Madhavi W. Chandra clearly define mobility and its requirements. They explain the Mobile Internet Protocol in detail to the level of message flows.

The "mobility" users appreciate today is in fact just nomadicity that lets clients connect to a network, get the related IP address, and communicate. True mobility, however, enables any end user and client to have one primary home address and use it during all communication, even on the move.

As for the networking layer requirements, the prime issue is always the address. This is where Mobile IP comes in. Mobile IP is an open specification of the Internet community that lets users keep the same IP address, stay connected, and maintain ongoing applications while roaming between IP subnets and networks. It enhances the classical IPv4 addressing and operation with the concept of home and foreign addresses, discovering and registering the mobile client with the closest router in the visited network, and routing to and from the client. This enables communication with the outer world as smooth as if the client never left its home network.

While mobility has already proven its merits within campus networks, it will be even more useful in metro areas. The mechanisms of reverse tunneling, firewall, NAT (network address translation) traversal, and integration with VPN technologies are needed. Mobility can occur on two levels, individual client and whole network (potentially nested within other networks), and Raab and Chandra cover both of these cases.

The next-generation IPv6 will enhance IPv4 because it embeds the mobile protocol and so provides native mobility support. In the section "A Look Ahead," the book touches briefly on mobility in IPv6, Layer 2 integration challenges, unstructured mobility, and mobile ad-hoc networking.

Raab and Chandra concentrate on configuration and management of Cisco clients, so they introduce IOS (Internetwork Operating System) command scripts wherever possible to support Cisco Mobile IP networks, covering issues such as redundancy, quality of service, and VPN configuration.

The protocol discussion would be incomplete without a word on security, a major problem for supporting mobile professionals and "mobile offices." Raab and Chandra explain protocol authentication and dynamic keying and emphasize the need for high-availability solutions and integration with AAA (authentication, authorization, and accounting) servers in campus networks.

The book is valuable because Raab and Chandra apply Mobile IP in real-world environments and show concrete Cisco IOS configurations. Their configuration, management, and troubleshooting explanations directly apply to common mobility needs. The book is useful for network administrators and other networking professionals who wish to become familiar with Mobile IP both in theory and in practice.

The text is designed for readers who are familiar with IP routing, networking protocols and applications, and wireless and mobile communication. Although the real-world situations are generic, Raab and Chandra explain configuration, troubleshooting, and management using Cisco IOS, so you'll need to know it as a prerequisite.

The book consists of nine chapters and two appendices. Each chapter includes questions that help self-study or classroom discussion. Appendix A provides the answers and brief explanations. Appendix B contains the SNMP (Simple Network Management Protocol) MIB (Management Information Base) objects supported by Cisco IOS Mobile IP. Unfortunately, Raab and Chandra didn't include a glossary or list of abbreviations, only an index. The text itself isn't flawless (beyond typos); for example, Raab and Chandra wrongly define the MAC layer as Message Authentication Code (p. 22).

As Cisco Fellow Fred Baker says in the foreword, "IP Mobility provides the ability not only for me to connect to the world at large but for it to find and connect to me." Always-on communication will need Mobile IP support, and this book helps you understand how to configure and operate Mobile IP in campus and metro networks while ensuring the necessary security.

Rita Pu manova is an independent networking specialist, technology writer, and trainer. Contact her at rita@ieee.org.