In a Windows NT Server domain, every Windows NT Server computer is a browser. One Windows NT Server computer in the domain, the primary domain controller if there is one, is the master browser, and the other Windows NT Server computers are backup browsers. If there is more than one Windows NT Server computer in the domain, no Windows NT Workstation computer will ever be a master browser in the domain.
In a workgroup containing Windows NT Workstation computers, there is always one master browser. If there are at least two Windows NT Workstation computers in the workgroup, there is also one backup browser. For every 32 Windows NT Workstation computers in the workgroup, there is another backup browser.