On Sunday 18 May 2003 19:18, Martin A. Brown wrote: > Maybe this is just for Stef? > > In answering Miernik's question (which Stef already answered), I read > this: > > http://www.docum.org/stef.coene/qos/faq/cache/13.html > > I thought it didn't matter what the rate was in a parent class? I thought > that it only mattered what the ceil was in a parent class. I'm doubting > myself now that I read this FAQ answer. > > My understanding: > > The parent class is only consulted by the child class when the child > class has exceeded its rate and wants to borrow from the parent. So, > the parent class rate is not consulted, but the ceil is used to > determine whether or not to lend? > > Is my understanding wrong? > > What's the story!? Take this example : tc class add dev eth0 classid 1:1 parent 1:0 htb rate 200kbps ceil 50kbps tc class add dev eth0 classid 1:10 parent 1:1 htb rate 150kbps ceil 128kbps tc class add dev eth0 classid 1:20 parent 1:1 htb rate 150kbps ceil 128kbps Both classes will get 150kbps. So no parent ceil/rate is checked/respected. I also did some tests to find out how the parent rate is used to split the traffic to child classes. Example : tc class add dev eth0 classid 1:1 parent 1:0 htb rate 200kbps tc class add dev eth0 classid 1:10 parent 1:1 htb rate 150kbps ceil 200kbps tc class add dev eth0 classid 1:20 parent 1:1 htb rate 50kbps ceil 200kbps tc class add dev eth0 classid 1:100 parent 1:10 htb rate 50kbps ceil 200kbps tc class add dev eth0 classid 1:200 parent 1:20 htb rate 50kbps ceil 200kbps And this results is 75% for class 1:10. But tc class add dev eth0 classid 1:1 parent 1:0 htb rate 200kbps tc class add dev eth0 classid 1:10 parent 1:1 htb rate 150kbps ceil 200kbps tc class add dev eth0 classid 1:20 parent 1:1 htb rate 50kbps ceil 200kbps tc class add dev eth0 classid 1:100 parent 1:10 htb rate 80kbps ceil 200kbps tc class add dev eth0 classid 1:200 parent 1:20 htb rate 80kbps ceil 200kbps gives 65% to class 1:100. So it's not clear to me how the rate of the parent is used in the calculations. It is, but I don't know how. For the ceil : tc class add dev eth0 classid 1:1 parent 1:0 htb rate 100kbps tc class add dev eth0 classid 1:10 parent 1:1 htb rate 150kbps ceil 100kbps tc class add dev eth0 classid 1:20 parent 1:1 htb rate 50kbps ceil 100kbps tc class add dev eth0 classid 1:100 parent 1:10 htb rate 20kbps ceil 200kbps tc class add dev eth0 classid 1:200 parent 1:20 htb rate 20kbps ceil 200kbps Total bandwidth is 200kbps. So the 100kbps ceil is never respected. Stef -- stef.coene@xxxxxxxxx "Using Linux as bandwidth manager" http://www.docum.org/ #lartc @ irc.oftc.net
