Hi! HTB questions: 1. why is quantum not always: quantum=mtu? From http://luxik.cdi.cz/~devik/qos/htb/manual/userg.htm: ------------< snip <------< snip <------< snip <------------ It is important to know that for precise operation quantums need to be as small as possible and larger than MTU ------------< snip <------< snip <------< snip <------------ Why isn't quantum just set to MTU then? Is there any advantages to having a bigger quantum? 2. why is mtu not just derived from the interface (you always have to specify the interface, so tc can just do a SIOCGIFMTU on the interface to get the MTU size)? 3. what is the difference between the priority which you can specify on the leaf nodes of the classes and the priorities you can specify in u32 match filters? does the one override the other? it seems that you have to specify the priority in a u32 match (to avoid the double display bug), so can you just specify prio 1 in all the u32 filters and then prioritize using classes - will that work or will the u32 priorities override the others? 4. could somebody please explain exactly what happens if the rates of children/subclasses within a root class exceed that of the root class/parent? does that influence other classes/qdiscs that does not fall within that hierarchy? (e.g. two classes 1:10 and 1:20 each have some classes below them - class 1:10 have more children in it than its rate, but 1:20 has less children / rate than its own rate - does the "oversold" rates in 1:10 influence 1:20?) 5. what happens if none of the rates of each class in a parent class exceed the parent's rate/ceil, but the total (i.e. sum of all the rates of the child classes) does exceed the parent's rate/ceil? 6. lets say I have a line with a certain rate - e.g. 512kbit, but I know for a fact that I can get a higher throughput through this line, lets say 768kbit. Now if I add a root qdisc with a root class in it rated at 512kbit and then add another child class in it with rate 512kbit and ceil 768kbit and then all my classes within that class - will the subclasses still respect their rate/ceil's? TC questions: 1. how does the classid's work? I must be stupid or something, but I just can't figure out how you're supposed to represent a hierarchy of classes with classid's. The way I understand it classid = <major>:<minor> and all the <major> numbers of classes within a qdisc must be the same as the qdisc (which have <minor> = 0), i.e. tc qdisc ... handle <x>: ... # root class in this qdisc tc class ... parent <x>: classid <x>:<y> tc class ... parent <x>:<y> classid <x>:<z> . . . So the qdisc handle is easy (just choose a unique major number), the root class in the qdisc is easy (just choose a unique minor number), but what do you use for the classes within the root class if you want multiple levels of classes, e.g. qdisc | +-- root class | +-- class 1 | | | +-- class 1.1 | | | +-- class 1.2 | +-- class 2 | +-- class 2.1 in above diagram, what would the classid's of classes 1, 2, 1.x, and 2.x be? 2. what happens if you have multiple root qdiscs? e.g. tc qdisc ... handle 1: root htb ... tc qdisc ... handle 2: root htb ... with some classes in each. Does the first qdisc get evaluated first, then the second or what? 3. what happens if you have qdiscs in non-leaf nodes within classes? -- Regards Abraham "Your butt is mine." -- Michael Jackson, Bad ___________________________________________________ Abraham vd Merwe [ZR1BBQ] - Frogfoot Networks P.O. Box 3472, Matieland, Stellenbosch, 7602 Cell: +27 82 565 4451 Http: http://www.frogfoot.net Email: abz@frogfoot.net
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