3.8. SGD Network Architecture

SGD is built around a three-tier network architecture model, consisting of the following tiers:

Different tiers can reside on the same host. For example, a single UNIX platform host can act as both an SGD server and an application server, but the tiers remain logically independent.

3.8.1. Client Devices

The first tier contains client devices. A client device is a piece of hardware that can communicate with SGD using a browser and the SGD Client.

The browser communicates with the SGD web server on the second tier and displays the webtop to users.

The SGD Client communicates with SGD servers on the second tier and displays the applications that users run.

The Adaptive Internet Protocol (AIP) ensures optimal network usage between the first and second tiers.

3.8.2. SGD Servers

The second tier contains SGD servers, which act as a gateway between the first and third tiers. This tier might contain a single SGD server, or many SGD servers configured to form an array.

An SGD server is responsible for the following:

  • Authenticating users when they log in to SGD

  • Negotiating with application servers to authenticate users when they run applications, prompting users for passwords when necessary

  • Causing the SGD Client to display applications

  • Keeping track of running applications even after users have logged out, so that they can resume them later

3.8.3. Application Servers

The third tier contains application servers that run users' applications.

When a user clicks a link on their webtop, SGD starts the application on an appropriate application server. Output from the application is redirected by the SGD server from the application server to the client device.

When you tell SGD about an application, you include information about all the application servers that can run the application. SGD load balances between the application servers.