Windows 2000 Browser System Overview

Windows 2000 and Windows NT assign tasks to specific computers on the network to provide browser services. The computers work together to provide a centralized list of shared resources, eliminating the need for all computers to maintain their own lists. This reduces the CPU time and network traffic needed to build and maintain the list.

The Windows 2000 browser system consists of a master browser, backup browsers, and browser clients. The computer that is the master browser maintains the browse list and periodically sends copies to the backup browsers. When a browser client needs information, it obtains the current browse list by remotely sending a NetServerEnum API call to either the master browser or a backup browser.

The browser system consists of two components, the browser service and the datagram receiver.

The browser service is the user-mode portion of the browser system and is responsible for maintaining the browse list, sending the API requests, and managing the various browser roles that a computer can have. The browser service actually resides within the Service Control Manager (Services.exe which calls browser.dll).

The datagram receiver is the kernel-mode portion of the browser system and is simply a datagram receiver and mailslot. It receives directed and broadcast datagrams that are of interest to the Windows 2000 Professional and Windows 2000 Server services. The datagram receiver also provides kernel-level support for the NetServerEnum API, support for remote mailslot message reception (second-class, datagram-based, mailslot messages), and the request announcement services.

In Microsoft® Windows NT® version 3.5 and later, the datagram receiver is implemented in the Windows NT redirector (Rdr.sys). In Microsoft® Windows NT® version 3.1, there is a separate driver, Browser.sys, for the datagram receiver.

The centralized browser architecture also reduces demands on the client CPU and memory.