cake: changing bandwidth on the rate limiter dynamically

[Jonathan Morton]

> On 12 Dec, 2014, at 17:52, Dave Taht <dave.taht at gmail.com> wrote:
> 
> Now, it turns out that cake makes altering the bandwidth really easy,
> you can just change it from the command line.
> 
> http://pastebin.com/Jr9s6EBW
> 
> I am pretty sure changing it is currently pretty damaging to stuff in
> flight (don't remember), but it needent be.

I don’t think it is harmful.  All that happens is that the packet issue deadlines start to be advanced at a different rate with each packet transmitted.  A change in the rate by that mechanism doesn’t cause any packet flushing or other trouble.

The flow-discrimination mode and the diffserv mode can also be changed in the same way, but this is more disruptive; it may at least result in some packets arriving out of order within flows, if not also some spurious drops.  But the network can tolerate that happening occasionally.

 - Jonathan Morton