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Re: Packet queueing; Not borrowing from parent queue



On Friday, Jan 30, 2004, at 11:45 US/Pacific, jared r r spiegel wrote:

[ on CBQ borrowing trouble ]

if you just can't get anywhere, maybe trying hfsc would be an option?

I'd echo this. While I can't say there isn't something wrong with the CBQ implementation, CBQ itself is oriented toward bandwidth limiting, with HFSC oriented toward guarantees.


i know hfsc doesn't seem to be as well documented or readily available documentation as cbq/priq, but i am working on uncovering the magic in hfsc and have been thus far very pleased with the results. it seems to handle gracefully me using 100Mb on the altq line and even using values in my <sc> settings as low as 488 b. it seems that 'realtime' is the bandwidth used when the link is not saturated, or the queue is not at 50/50 or whichever; and 'linkshare' is what it uses instead when the link is saturated.

'realtime' is the minimum guarantee; it will always be satisfied. 'linkshare' is for sharing the remaining bandwidth, after all 'realtime' guarantees have been taken care of. pf also has 'upperlimit' for a hard limit. So a queue will get "bandwidth = realtime <= (excess weighted by linkshare) <= upperlimit". Or should, anyway :)


The URL you were going to post didn't show, but HFSC's home page is http://www-2.cs.cmu.edu/~hzhang/HFSC/ and I've found the presentation there useful. kjc's notes in http://www.csl.sony.co.jp/person/kjc/kjc/software/TIPS.txt are useful for a less theoretical overview. Even so, I can't claim to be an expert myself, it's taken quite a while to sink in...