[Cake] fq_codel on 3g network in Mauritius
chromatix99 at gmail.com
Tue Jul 19 04:09:27 EDT 2016
> On 19 Jul, 2016, at 07:29, Loganaden Velvindron <loganaden at gmail.com> wrote:
> I've been playing with fq_codel on 3g internet connection. the 3g
> internet box has no bridge mode, and just forwards every packet to the
> Openwrt router.
> Here are the results without:
> And here is the result with fq_codel on and 300 ms target latency:
> Is there anything that could be done to get the rating up to A+ by
> tweaking the code ?
You say fq_codel, rather than Cake. Presumably it is paired with some sort of shaper, such as HTB? This is important, because I think the shaper is influencing part of your results.
On downstream, you have one high latency sample (750ms) in the middle of a series of reasonable ones (250ms). This implies a momentary glitch in your connection, which isn’t unusual with wireless links. Re-measuring might eliminate it.
On upstream, you have two very high latency samples at the *beginning* of the run, which then clear out to approximately the baseline latency. This is a classic sign that your shaper is letting a burst of traffic through before actually starting to control it, which is typical behaviour for token-bucket shapers. That initial burst collects in the dumb queue of your 3G modem and takes time to drain away.
Cake uses a shaper carefully designed to *not* burst in that manner, while still maintaining full throughput regardless of timer resolution and latency. Using Cake instead of fq_codel+HTB will therefore probably improve your upload characteristics.
- Jonathan Morton
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