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To have the light load on the control-plane, we use an appropriate sequential order of access to OpenFlow switches.
First, the OpenFlow controller calculates the packet loss rate of each of the terminal paths with the information at the root port and leaf ports.
if the packet loss rate of a terminal path is less than the threshold value h, this terminal path does not include a high-loss link.
Otherwise, this terminal path is likely to include one or more high-loss links. The correlation among terminal paths in terms of the degree of packet loss can be used to narrow the search scope.
If a terminal path is high-loss but all other terminal paths sharing at least one link with the high-loss terminal path are not, the high-loss links are located within a segment between the leaf port and the nearest branch port of the single high-loss terminal path. The dashed line on the left part in Figure 10 illustrates an example of this case. Then, the binary search algorithm is used to locate all high-loss links by accessing appropriate ports.
On the other hand, if there are multiple high-loss terminal paths, the next port to access is the most commonly port shared by those paths. An example of this case is shown in the right part of Figure 10. |
IEEE/ICACT20210168 Slide.15
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