[Cerowrt-devel] archer c7 v2, policing, hostapd, test openwrt build

Jonathan Morton chromatix99 at gmail.com
Sun Mar 22 21:34:48 EDT 2015

> On 23 Mar, 2015, at 02:24, Dave Taht <dave.taht at gmail.com> wrote:
> I have long maintained it was possible to build a better fq_codel-like
> policer without doing htb rate shaping, ("bobbie"), and I am tempted
> to give it a go in the coming months.

I have a hazy picture in my mind, now, of how it could be made to work.

A policer doesn’t actually maintain a queue, but it is possible to calculate when the currently-arriving packet would be scheduled for sending if a shaped FIFO was present, in much the same way that cake actually performs such scheduling at the head of a real queue.  The difference between that time and the current time is a virtual sojourn time which can be fed into the Codel algorithm.  Then, when Codel says to drop a packet, you do so.

Because there’s no queue management, timer interrupts nor flow segregation, the overhead should be significantly lower than an actual queue.  And there’s a reasonable hope that involving Codel will give better results than either a brick-wall or a token bucket.

 - Jonathan Morton

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