What if your next ERP or CRM package was as easy to implement as your firewall? That's the goal of providing software as an appliance, an approach that might make sense for any organization struggling with the complexities of buying, deploying and managing enterprise software.

Enterprise software - think SAP, Oracle, PeopleSoft-has its problems. Namely, it's expensive, complex, and difficult to deploy and manage. In fact, adding new applications into corporate environments usually means embarking on a lengthy integration project that often provides more headaches than functionality.

The industry's previous attempt to address such complexity resulted in the application service provider (ASP) model. With an ASP, deployment requires only an Internet connection and a Web browser, and the software comes as part of a leased, pay-as-you-go model, significantly easing up-front costs. ASP-provided software also is available on a modular basis, enabling organizations to buy and use only the functionality they need rather than integrating a huge feature-bloated software suite to get a few key functions.

Unfortunately, ASPs don't address all of today's business problems, such as data privacy and compliance issues.

"Essentially, an ASP model forces you to take user and customer data that is core to your business - HR, CRM or Web analytics, for example - and put it outside your corporation, under the watch of a much smaller, and oftentimes not-yet-profitable, young ASP," says Peter Relan, CEO of software start-up Business Signatures. "That's simply not tenable for most organizations faced with compliance issues today."

Enter the software appliance, which Relan says provides the best of the ASP and enterprise-site models. Like ASP software, a software appliance is modular, Web-based and available on a leased or pay-as-you-go basis. The self-contained software modules include the core application logic running on top of an open source software stack - operating system, Web server and so forth. They have their own application-specific database and data management tools, and use the standard XML Web services API for all data import and export. Customers simply plop the software appliance on to a bare metal server and it runs. Just like a typical hardware appliance, no care and feeding is required by database administrators or operations personnel.