The Downside

There is a downside to any distributed architecture. We’ve covered most of them in this chapter and suggested workarounds - security, state, speed, and connectivity. Let’s go over them once more to ensure that Web Services are the way to go.

Security

The key to the issue and solution of security problems is the management of client expectations. If Web Services are built securely to begin with, then you won’t face situations that draw concern or scrutiny. Consider the security of everything you write. It’s fairly easy, and the payoff is great.

State

State is less of a problem in a distributed architecture because in Windows DNA, Microsoft has been saying for years that n-tier statefulness has to go. Most developers are used to the idea, but if you aren’t, then you need to get on the boat with the rest of us. Architect your solutions to be loosely coupled. That’s what Web Services are designed to do.

Transactions

Web Services are not made for transactional systems. If the Web server at MyCompany.com was to access a database at UPS, for example, and the connection dropped in the middle, the lock on the database would remain without giving the network system at UPS a chance to solve the problem. Web Services are by nature loosely coupled. They are not designed for tight transactional integration.

A common use of Web Services, communication between differing systems, prompted a number of technology architects to design several XML transaction protocols, such as 2PC. These packages provide the two systems with an understanding that the network link will remain stable.

Speed and Connectivity

Speed and connectivity are going to be a continuing problem until we have the ubiquitous bandwidth George Gilder talks about in his book Telecosm (Free Press, 2000). Right now, the majority of Internet devices that could really benefit from Web Services - cell phones, PDAs, and the like - are stuck at the paltry 14,000-bits per second currently supported by most wireless providers.

For application development, this is a concern because when the router goes down, the application goes down. Right now, intranets continue to function when the ISP drops the ISDN. With Web Services running the links to customers and suppliers, that ISDN line becomes the company lifeline. Redundancy of connections and a firm partnership with your service provider are the only solution.