一项网络工程的建设流程通常由

①对现有网络的体系结构进行分析，

②网络需求分析，

③确定网络物理结构，

④确定网络逻辑结构，

⑤安装、测试和维护等5阶段组成，

根据网络开发设计的过程，对这5个阶段的先后排序正确的是()。

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In low-speed network, it is usually adequate to wait for congestion to occur and then react to it by telling the source of packets to slow down. In high-speed networks, this approach often works poorly, because in the(71)between sending the notification and notification arriving at the source, thousands of additional(72)may arrive. In ATM network, a major tool for preventing(73)is(74)control. When a host wants a new virtual(75),it must describe the traffic to be offered and the service expected.

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To a router, a flow is a(66)of packets that share the same Characterstics, such as traveling the same(67),using the same(68),having the same kind of security, and so on. A router that supports the handling of flow labels has a(69)table. The table has an entry for each active flow label; each entry defines the(70)required by the corresponding flow label.

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