On Thu, May 25, 2017 at 2:36 AM, 爬山虎 <[email protected]> wrote: > > hi all: > > I am going to implement the meter speed limit. I read the book of > "ovs-ofctl.pdf " about the instructions of burst. In this pdf book , the > instructions of burst is : If multiple bands' rate is exceeded,then the > band with the highest rate among the exceeded bands is selected . It's a bit > confused for me . > > I think whether this burst problem is complicated . for example, > ovs-ofctl add-meter br1 meter=1, kbps,burst, band=type=drop, rate = 3000, > burst_size=5000 . > > That's enough and also very easy to understand. if download speed is more > than 3000 kbps, then just discarding the packages. > > But the burst is hard to understand. According to my own understanding (just > think about TC) , we can see burst to be a buffer bucket. If there is nobody > use bandwidth, or bandwidth rate is less then 3000 kbps , the token will > accumulate in the bucket, but the maximum value is 5000 kbps. Next time the > user can use 5000 kbps bandwidth but only in a second.
This sounds correct, only the time period may not be strictly to the second boundary. If user can use up > 3000 kbps bandwidth ,then it will be limited at 3000 kbps. > I don't follow this sentence. DId you mean to say that if a user sends constant 3000kbps traffic, then the bandwidth is limited to 3000kbps, without burst allowance? If yes, then I'd agree. If no, would please clarify? > Now ovs allow to set multiple band values , this is a little worse. > > just for example . > ovs-ofctl add-meter br1 meter=1, kbps,burst, band=type=drop, rate = 3000, > burst_size=5000 type=drop, rate = 4000, burst_size=6000 . > > I cant understand this . if according to ovs-ofctl.pdf , when rate could up > 5000, then it limit value is 4000. when rate could up 6000, then it limite > value is 3000 . This is not very reasonable, we have bein in the case of a > speed limit . Can be more than 5000 kbps , has a great deal of randomness. I think we should first determine the rate of current traffic, and use the rate to select a band. Once the band is selected, the burst_size can be used to determine the fate the packet. > > How to design the burst in here , has some suggestions ? > You may find the book of openflow specification helpful. https://www.opennetworking.org/images/stories/downloads/sdn-resources/onf-specifications/openflow/openflow-switch-v1.5.1.pdf _______________________________________________ discuss mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
