This chapter is from the book
This chapter is from the book
This chapter is from the book
Hosted Application Implementation
The ASP implements the hosted application in roughly chronological phases. First, the ASP has to decide the functionality that is needed to meet your business requirements. If you lease a turnkey, generic hosted application, the ASP can commit to a predetermined schedule. After all, little customization between legacy and hosted applications is needed. However, if customization is required, the ASP must estimate the extent of it and work out the fee it will charge you. For example, the fee might be based on time and materials for the whole project or be a flat fee for specific work.
Next, the ASP must size your solution. This phase, too, can be less or more complicated according to different factors. If the ASP makes you conform to its own system platform, sizing is easy. You have already decided to forego customization and will adapt your work processes to the hosted package. If you require that the generic application be customized, then the ASP must tailor the software to your unique specifications.
To size hardware, the ASP must decide the number, type, and use of computers to be deployed, and the system architecture of the solution. For instance, will different types of servers be used as firewalls, database, and Web servers? At this phase, the ASP also will typically decide on disk space for each computer and storage capacity for storage devices. This estimate should take into account user data accrued over the period of the contract. The same goes for servers. The ASP must estimate "headroom"—how many additional servers and how much rack space you'll require—as well as whether the servers will be dedicated to you or shared by you and other customers. Any hardware architecture decisions like whether to cluster servers should be made at this point. And, of course, the ASP must choose processors powerful enough to drive those servers.
Actual platform preparation usually involves loading the operating systems, partitioning drives (logically dedicating drive capacity in the same server to different users, departments, and so on), loading the servers and storage devices into the racks, and deploying network firewalls at your customer premises and the data centers.