Secure Global Desktop Administration Guide > Getting started > Introducing the three-tier architecture

Introducing the three-tier architecture

Secure Global Desktop is built around a three-tier architecture model:

Different tiers can reside on the same host (for example, a single UNIX host can act as both a Secure Global Desktop server and an application server), but the tiers remain logically independent.

The first tier: client devices

A client device is a piece of hardware that can communicate with Secure Global Desktop using a web browser and the Sun Secure Global Desktop Client.

The web browser communicates with the Secure Global Desktop Web Server on the second tier and displays the webtop to users.

The Sun Secure Global Desktop Client communicates with Secure Global Desktop 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.

The second tier: Secure Global Desktop servers

The second tier may contain a single Secure Global Desktop server, or many Secure Global Desktop servers configured to form an array.

A Secure Global Desktop server is responsible for:

• Authenticating users when they log in to Secure Global Desktop.
• Negotiating with application servers to authenticate users when they run applications, prompting users for passwords when necessary.
• Causing the Sun Secure Global Desktop Client to display applications.
• Keeping track of running applications even after users have logged out, so that they can resume them later.

The third tier: application servers

An application server runs users' applications.

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

When you tell Secure Global Desktop about an application, you include information about all the application servers that may run the application. Secure Global Desktop load balances between the application servers.

Summary

• Secure Global Desktop is based around a three-tier architecture.
• The first tier contains client devices. Web browsers let users access Secure Global Desktop and display webtops. The Sun Secure Global Desktop Client displays applications that users run.
• The second tier contains Secure Global Desktop servers, which act as a gateway between the first and third tiers.
• The third tier contains the application servers that run users' applications.

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