[Cake] COBALT implementation in ns-3 with results under different traffic scenarios

[Jonathan Morton]

> On 9 Dec, 2018, at 10:37 am, Jendaipou Palmei <jendaipoupalmei at gmail.com> wrote:
> 
> By hidden queues, do you mean the NIC buffers? ns-3 has a Linux-like traffic control wherein the packets dequeued by a queue discipline are enqueued into NIC buffer.

That's right.  Linux now uses BQL, which (given compatible NIC drivers) limits the number of packets in the NIC buffers to a very small value - much smaller than is evident from your data.  If you were to measure the end-to-end RTT of each, I'm certain you would see this effect dominating the mere 50ms latency you're trying to model.

Ideally, AQM would applied to the hardware queue anyway.  For simulation purposes, I recommend reducing the NIC buffer on the bottleneck interface to 1 packet, so that the simulated AQM's effects are easiest to measure.

 - Jonathan Morton