D-Link DGS-3308TG, Руководство пользователя

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8-port Gigabit Ethernet Switch User’s Guide
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Consider, for example, a typical corporate intranet. Most use a hierarchy that consists of a high-speed backbone network
with multiple routers each connecting the backbone to a workgroup, where each workgroup occupies a single LAN. Although
the corporation can include dozens of workgroups, the span of the entire intranet is only 2. Even if each workgroup is
extended to include a router that connects one or more additional LANs, the maximum span only increases to 4. Similarly,
extending the hierarchy one more level only increases the span to 6. Thus, the limit that RIP imposes affects large
autonomous systems or autonomous systems that do not have a hierarchical organization.
Even in the best cases, however, hop counts provide only a crude measure of network capacity or responsiveness. Thus,
using hop counts does not always yield routes with the least delay or highest capacity. Furthermore, computing routes on
the basis of minimum hop counts has the severe disadvantage that it makes routing relatively static because routes
cannot respond to changes in network load.