[Cake] ER-X now running cake, thanks for the help. :)

[Sebastian Moeller]

Hi Erik,


> On May 5, 2017, at 15:55, erik.taraldsen at telenor.com wrote:
> 
>> Fra: Sebastian Moeller <moeller0 at gmx.de>
> 
>> .. snip <good explanations and tips> 
>> One problem with the unelastic load is that as far as I can tell no flow on the open internet is 
>> allows/assumed to behave like that (isn’t the default tcp-friendly, and inelastic DOS traffic is 
>> essentially out-lawed?)
> 
> You are right in that single stream udp without any feedback is a quite unrealistic load.  It is however usually a good indicator of possible trouble with bufferbloat.  When I get delays in the multiple seconds range there usually is no point in running more realistic tests such as flent, so I tend to start with that udp test before setting up a lab.  Current record found in production systems is 34 seconds.

	I beg to differ somewhat. With fq_codel and cake the high-bandwidth in-elastic UDP flow (heck an in-elastic TCP flow would be the same) really is just testing the DOS case and effectively probing the worst case memory buffer behind the AQM. So I believe this is a valid test, but it is not a show-stopper if this test shows deep buffers. Netalyzr basically does that (and it also measures for short durations so that fq_codel/cake have problems ramping their drop probability high enough in time to make dent into the load). Under normal operating conditions however that buffer will never fill up and hence can be considered harmless (or actually helpfull, as it allows to straighten out bursty traffic).

Best Regards
	Sebastian


> 
> I'll redo the test using flent in the lab next week, using both fq_codel and cake.
> 
> -Erik