Microsoft Systems Management Server 2003 : Developing Site Hierarchies (part 1) - Network Performance

Figure 1. SMS hierarchy viewed through the SMS Administrator Console.

SMS sites, as we have seen, are identified by the site boundaries that you assign. Clients are assigned to an SMS site based on either IP subnet or Active Directory directory service site boundaries. As such, a multinational organization with locations in different countries could be managed by one large SMS site or by individual SMS sites in each location connected to a central site. Figure 2 illustrates an example hierarchy. Contoso, Ltd. has a corporate office in Chicago and regional offices in New York, London, and Tokyo. Each office has its own IP subnet. The single SMS site, located in Chicago, could manage all Contoso locations because it includes all the IP subnets in its site subnet boundaries.

In contrast, Figure 3 shows the same organization, but this time with individual SMS sites in each region, each reporting back to a central site located at Contoso headquarters in Chicago.

Figure 3. The Contoso site hierarchy, with multiple SMS sites.

Many factors and circumstances can affect your site structure strategy. Each must be considered carefully before implementing the hierarchy. These factors are likely to include, but are certainly not limited to, the following:

• Network performance

• SMS client components

• Location and number of clients

• International site considerations

• Administrative model of the organization

• Active Directory domain model

Let’s look at each of these factors in detail.

Network Performance

Network performance issues will no doubt be the single most significant factor in determining what your site structure should look like. Varying amounts of network traffic are generated among SMS site servers, SMS site systems, and SMS clients. Site servers communicate package, advertisement, and site configuration data to their site systems. The amount of traffic that’s generated depends on the nature of the data being sent. For example, a site that distributes three packages a day with an average size of 50 MB to 10 distribution points is generating 500 MB of network traffic three times a day. This traffic could be significant on an already crowded network infrastructure. Or suppose that hardware inventory files representing only changes that have occurred are collected from a group of 32-bit SMS clients. If inventory is collected once a week from 5000 clients, the amount of traffic generated is probably not going to be significant. Even at 100 KB per client—the average size of a full default inventory file—this traffic would total 500 MB once a week and would largely be randomized.

Network traffic concerns are particularly significant when SMS traffic must cross WAN connections. You might ask yourself whether the existing WAN connections are well connected and efficient enough to handle the traffic generated between the proposed SMS site systems or whether it would make more sense to create an additional SMS site at the other end of a WAN connection. Let’s return to our Contoso example. Suppose that you need to send a 50 MB package from the site server in Chicago to 10 distribution points in New York, as illustrated in Figure 4. This transaction will generate about 500 MB of package distribution traffic across the WAN connection between Chicago and New York because SMS must deliver the entire package to each distribution point individually within the same site—and generally uncompressed.

On the other hand, SMS sends packages from one site to distribution points in another site by sending the package to the target site once and letting the target site distribute the package to its local distribution points. Furthermore, it generally sends the package to the target site in a compressed format. As illustrated in Figure 5, the amount of WAN traffic generated for the same package scenario is considerably less—only about 25 MB as opposed to around 500 MB. Your site deployment strategy should already have assessed and predicted how you’ll use SMS and the amount of data that you’ll be generating within the site. Armed with this information, consider its effect on the current network traffic patterns and volumes, especially across WAN links, when deciding whether to implement one large SMS site or several SMS sites participating in a site hierarchy.

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