The servers are OGC-compliant Ind integrate well with other enterprise software so that you can integrate GIS with many technologies and computing standards.
There is the description of the basic components of ArcGIS Server, which helps to understand the main principles below of ArcGIS for Server:
GIS-Server conducts the requests received by the Web services. It is applied for map rendering, launching geoprocessing tools, handling the data requests and performing any other actions that are available in the service. GIS server can consist of one or several computers working together, the number of which can be easily increased or reduced. GIS server provides access to the services on standard HTTP. After installing the GIS server, you will immediately receive a set of web services that you can use in your applications. GIS servers can be organized in groups called clusters. Each cluster processes a set of services that are configured by the server administrator.
A web server can host web applications and provide optional security and load balancing benefits to your ArcGIS Server site. If you just need basic hosting of GIS services, you can use the site that you create after installing ArcGIS Server.
If you need to go beyond simple hosting of services, or if you want to use your organization's existing web server, you can install the Web Adaptor. The Web Adaptor allows you to integrate your ArcGIS Server site with IIS, WebSphere, WebLogic, and other web servers.
Web Adaptor is used to integrate GIS servers with existing corporate web server. Web Adaptor receives requests to Web services through a common URL (on your chosen port and the name of the site) and sends them to the various GIS server machines in your site. You can also provide access to the site with the help of other "Web Gateway" technologies, for example, load balancing, HTTP, network router. In some cases, you can use Web Adaptor with existing solution for load balancing.
Data server is used to place data directly on each GIS server or get access to it from central data storage, for example, from a network shared folder or ArcSDE geodatabase. Whichever option is selected the data contains all GIS resources, published as a service to the GIS server.