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资源分配中的问题
分组交换网络在相互竞争的流之间分配带宽，这一过程分为两项任务：拥塞控制，即在需求超过供给时防止网络窒息；以及资源分配，即公平地分配现有资源。这两者容易与流量控制混淆——流量控制是另一回事，即不让慢速接收方被淹没。设计空间沿三个轴线分类：路由器中心还是主机中心的智能、预留还是反馈、窗口还是速率。而成功与否由处于张力之中的吞吐量与时延来衡量，概括为功率，公平则是默默无闻的第二准则，决定当网络说“不”时由谁来承担痛苦。
1. Two Jobs, One Scarce Resource
Two Jobs, One Scarce Resource
2. Not a Routing Problem
Not a Routing Problem
3. A Taxonomy of Responsibility
A Taxonomy of Responsibility
4. Measuring Success
Measuring Success
5. Three kinds of no
A sender's packets are dropped because the destination's receive buffer is full. Which mechanism was supposed to prevent this?
6. Where the smarts live
What distinguishes a host-centric congestion mechanism from a router-centric one?
7. Ask first or adjust later
What separates a reservation-based approach from a feedback-based one?
8. The power curve
What does the power metric, throughput divided by delay, capture about a congestible network?
9. Stability
What does it mean for a congestion control mechanism to be stable?
10. Windows and rates
Why are rate-based controls natural for multimedia reservations while window-based controls suit stream transports?
11. The protected party
Flow control protects the slow receiver, while congestion control protects what?
12. The dividing ratio
What is the classic metric that divides throughput by delay to summarize a congestible network's operating point?
13. The bad regime
What is the name of the catastrophic regime where the network carries packets only to discard most of them downstream, and almost no useful work completes?
14. The asking approach
In which approach does a source declare its needs and get admitted or rejected before it may send any data?