Browse Service Across an IP Router

When using domains that are split across routers, each TCP/IP network subnet functions as an independent browsing entity with its own master browser and backup browsers. Therefore, browser elections occur within each network subnet.

Domain master browsers are responsible for spanning the network subnets to collect computer name information to maintain a domain-wide browse list of available resources. The domain master browser and cooperating master browsers on each subnet provide browsing of domains that exist across multiple TCP/IP network subnets. The domain master browser is the PDC of a domain. The master browser computers on the subnets can be running Windows 2000, Windows NT, Windows for Workgroups version 3.11b, Windows 95, or Windows 98.

Figure I.8 shows Browser Service across an IP router.


Figure I.8 Browser Service Across an IP Router

When a domain spans multiple network subnets, the master browsers for each network subnet use a directed datagram called a MasterBrowserAnnouncement to announce themselves to the domain master browser. The MasterBrowserAnnouncement notifies the domain master browser that the sending computer is a master browser in the same domain and that the domain master browser needs to obtain a copy of the master browser's browse list. When the domain master browser receives a MasterBrowserAnnouncement, it returns a request to the announcing master browser for a list of the servers in the master browser's network subnet. The domain master browser then merges its own server list with the server list from the master browser that issued the announcement.

This process is repeated every 15 minutes and guarantees that the domain master browser has a complete browse list of all the servers in the domain. When a client issues a browse request to a backup browser, the backup browser returns a list of all the servers in the domain, regardless of the network subnet on which they are located.