| Resource Allocation | Admission Control | Routing | Packet Forwarding |
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Resource Allocation (頻寬分配)
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Real-time vs. Pre-Planning
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How to allocate bandwidth to Ingress?
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How to best use acqiured bandwidth?
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Admission Control
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Admission controller of an Ingress decides to accept or
reject each imcoming request based on the local resources availability
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當頻寬分配的決策定下來之後，Ingress 執行 admission control
以接納個別顧客之需求，admission control 必須就所擁有的頻寬資源
調配，再決定是否接納顧客。
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Routing
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traditional routing algorithms are not timing aware
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may not be able to control delay time and jitter
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Real-time routing vs. Pre-Routing
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在 Admission control 中，routing 是一個重要的功能。而現有的 routing
方法多半沒有考慮 delay time, jitter, packet loss 等品質需求，
有必要發展新的 routing 方法。Routing 可採用事先規劃事先根據
需求之品質等級與目的地設定之方法，也可以採用 real-time 的方式，
當顧客進來之時才當場做routing。
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Packet Forwarding
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DiffServ uses Per Hop Behavior
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External routing approach needs to change the packet forwarding
mechanism
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DiffServ 採用per-hop 方式管理，每個網路元件在轉送封包時，
主要根據目的地轉送，在 aggregation-by-Ingress 的方法下，
必須配合修改，要根據 Ingress 與 目的地轉送封包。
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