Q&A

Q1:	Why do many IP addresses go unused?
A1:	An organization that is assigned an Internet address space often doesn't use all the host IDs associated with that address space.
Q2:	What is the advantage of placing header information in an extension header instead of in the main header?
A2:	The extension header is included only if the information in the header is necessary. Also, many extension headers are not processed by routers and therefore won't slow down router traffic.
Q3:	All clerical workers in my office just received new super-charged workstations with over a hundred built-in programs and thousands of configuration options. My TCO consultant is not impressed. Why not?
A3:	The Total Cost of Ownership (TCO) of a workstation is not just the list price of the computer but also the cost of configuring, operating, and maintaining it. A simple system that is easy to configure and doesn't offer superfluous options is often more cost effective than a complicated and advanced system that will be harder to operate and will offer the user more opportunities to get lost.
Q4:	I manage the network for a poor orphanage with a meager endowment. To save money, I'm thinking about deploying a storage area network (SAN) to maintain personal and financial records. When I explain my situation, the vendors won't return my calls. Why not?
A4:	A storage area network is an extremely advanced, high-performing solution that is very expensive. A poor orphanage would not have the money for it. Also, an orphanage probably wouldn't have the need for a storage area network. Storage area networks are designed for mission-critical data centers that hold millions of records.
Q5:	What are the reasons for deploying a server cluster?
A5:	Grouping servers into a cluster offers improvements in speed and processing power. A cluster also provides fault tolerance because if one server goes down, the others will continue to provide services.
Q6:	I'm working on a program that will perform a maintenance check on my hard drive and correct any disk errors. Should I use a Web services architecture for this application?
A6:	The Web services architecture leverages the tools of the Web infrastructure to access services on the network and to provide efficient input and output for remote transactions. Although it might be theoretically possible to invoke a maintenance check through a Web interface, the advantages of the Web services architecture are not very relevant to this program, and would probably not be a programmer's first choice.
Q7:	I'm working on a new program that will let users on a corporate network place and track requests for specialized training seminars offered by the company. Should I use a Web services architecture for this application?
A7:	Tasks that require remote users to enter and access data from a central database are well suited for the Web services architecture. This situation sounds like a good fit for Web services.