Browsing is a critical aspect of any Windows workgroup. However, not everything runs perfectly on any network. For example, let's say that the Windows NT Server on the desk of a small company's CEO is the local master browser - that is, until he switches it off while plugging in his massage chair. At this point the Windows NT Workstation in the spare parts department might agree to take over the job. However, that computer is currently running a large, poorly written program that has brought its processor to its knees. The moral: browsing has to be very tolerant of servers coming and going. Because nearly every Windows machine can serve as a browser, there has to be a way of deciding at any time who will take on the job. This decision-making process is called an
election.
An election algorithm is built into nearly all Windows operating systems such that they can each agree who is going to be a local master browser and who will be local backup browsers. An election can be forced at any time. For example, let's assume that the CEO has finished his massage and reboots his server. As the server comes online, it will announce its presence and an election will take place to see if the PC in the spare parts department should still be the master browser.
When an election is performed, each machine broadcasts via datagrams information about itself. This information includes the following:
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The version of the election protocol used
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The operating system on the machine
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The amount of time the client has been on the network
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The hostname of the client
These values determine which operating system has seniority and will fulfill the role of the local master browser. (Chapter 6,
Users, Security, and Domains , describes the election process in more detail.) The architecture developed to achieve this is not elegant and has built-in security problems. While a browsing domain can be integrated with domain security, the election algorithm does not take into consideration which computers become browsers. Thus it is possible for any machine running a browser service to register itself as participating in the browsing election, and (after winning) being able to change the browse list. Nevertheless, browsing is a key feature of Windows networking and backwards compatibility requirements will ensure that it is in use for years to come.
