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

[Jonathan Morton]

> On 5 Dec, 2018, at 2:23 pm, Jendaipou Palmei <jendaipoupalmei at gmail.com> wrote:
> 
> We have uploaded the corresponding graphs for reference CoDel. 
> 
> Link: https://github.com/Daipu/COBALT/wiki/Drop-Count-Graph

Quite a remarkable difference here - just look at the scales for the corresponding graphs!  I'm actually rather surprised to see reference Codel reaching such deep activation states, when COBALT stays very shallowly activated but is still effective.  It makes me wonder whether there's something odd going on with the ns3 version of Codel.

I'm sure more insight will be gained from the actual drop traces.

> We have also plotted the instantaneous throughput for all flows in Light traffic scenario for COBALT and CoDel.
> These graphs are plotted for packet size with 1000 bytes and 1500 bytes.
> 
> Link: https://github.com/Daipu/COBALT/wiki/Throughput-for-Separate-Flow

This isn't quite what I was thinking of, but it's still interesting.  I was looking for all flows from a single run plotted on a single graph, perhaps stacked so that their sum is visible as overall throughput.  That way, the interaction between one flow backing off and others taking over its unused capacity becomes clearer, and it is possible to see if more than one flow backs off at the same time (indicating that both got hit by AQM).

There are also sampling artefacts apparent in these graphs as rapid oscillations around a mean value.  You might want to look into ways to eliminate or otherwise account for those.

> We're currently working on the following:
> 
> 1. plots for the actual number of marks/drops per time interval for COBALT, CoDel, and PIE.
> 2. zoomed in plots on small time intervals to show the dynamic behavior of the algorithm.
> 3. a file showing the timestamp of each drop.

I await these with interest.

 - Jonathan Morton