【正文】 in these cases it may also be prudent and/or more efficient to allow some of the administrative tasks to be performed at the regional or remote locations. This is done by “delegating” very specific authority to the remote location resources. “Very specific authority” refers to a small subset of administrative rights and access that allow the remote administrators to perform specific, discrete tasks. Service Management Function 13 Figure 5 shows a possible application of the centralized/remote administration model. Figure 5. A centralized/delegated administration model Distributed Administration of Distributed Hardware Unlike the other models, distributed administration, shown in Figure 6, relies on full support resources located in remote sites or branch offices. Resources at remotely located sites perform the fundamental (although critical) support functions necessary to maintain the health, availability, and reliability of systems distributed to those sites. There may continue to be business reasons for maintaining systems that are distributed to remote locations. Some of these reasons may be related to performance, scalability, a specific type of application, or the cost or availability of work bandwidth that would support a centralized solution. 14 System A dministration Figure 6 shows an example of a distributed administration model for a pany with remote sites that are heavily populated with puter users. Figure 6. Completely distributed administration model As shown in Figure 6, puting and people resources are pletely distributed to the remote offices and regional sites. As a result, the pany may realize much better local site performance for specific technology applications. Specific Application Reasons for the Distributed Model Decision Here is an example of an application that affects the decision to distribute the environment (and subsequent administration thereof). Electronic messaging is one of the most critical applications that panies deploy to improve panywide productivity, munications (both internal and external), and puting efficiency for their businesses. Typically, early mainframebased messaging solutions were pletely centralized—both the hardware and the administrative support functions were centrally located in the pany’s data center. When personal puters and, eventually, serverbased, local area works (LANs) of personal puters became widely embraced and deployed, many panies decided to move the messaging applications from the mainframe to the serverbased works. This decision hinged primarily upon three factors: the unique richness available in the serverbased products and solutions, the cost benefits realized by downsizing applications from the more expensive mainframes to the less expensive servers, and the power that users realized by having a fullfeatured, localized, messaging client on their personal puter. For the most part, these early serverbased messaging solutions were, by necessity, distributed. Known by the type of message transport mechanisms they employed, these solutions were described as “storeand forward.” They required that the “post office” (hub server where the electronic form of the message database and message transport mechanisms executed) be close to the users whose accounts it hosted. In other words, the post office was connected to the users through a LAN. Consequently, the service that could be provided on these high speed LANS was defined as “LANspeed,” as opposed to “WANspeed,” which indicates that the service is being made available from a distant location and travels across the pany’s widearea work links. The benefits of this distributed design were better performance and scalability (defined as the number of users that could be connected to, or hosted by, a single post office). Users Service Management Function 15 enjoyed an additional benefit as well。 System Administration Service Management Function Published: October 20xx Reformatted: January 20xx For the latest information, please see ii System A dministration The information contained in this document represents the current view of Microsoft C orporation on the issues discussed as of the date of publication. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a mitment on the part of Mic rosoft, and Microsoft cannot guarantee the accuracy of any information presented after the date of publication. This document is for informational purposes only. MICROSOFT MAKES NO WA RRANTIES, EXPRESS, IMPLIED O R STATUTORY, A S TO THE INFORMATION IN THIS DOCUMENT. C omplying with all applicable copyright laws is the responsibility of the user. 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