[Cake] [Codel] Proposing COBALT

[Jonathan Morton]

> On 20 May, 2016, at 19:20, Rick Jones <rick.jones2 at hpe.com> wrote:
> 
> On 05/20/2016 08:12 AM, Jonathan Morton wrote:
>> 
>>> On 20 May, 2016, at 17:04, David Lang <david at lang.hm> wrote:
>>> 
>>> Is it possible to get speed testing software to detect that it's receiving fragments and warn about that?
>> 
>> Do iperf3’s maintainers accept patches?
> 
> Netperf's maintainer has been known to accept patches so long as they aren't too hairy.  That said, it isn't clear how something operating above the socket interface is going to know that the traffic it was receiving was in the form of reassembled IP datagram fragments.
> 
> happy benchmarking,
> 
> rick jones
> 
> I suppose if said software were to dive below the socket interface it could find-out, though that will tend to lack portability.

I’m a little fuzzy on UDP socket semantics.

Could the sender set DF on a small proportion of the packets, and listen for ICMP errors to the effect?  These packets could also be salted with distinguishable data so that the receiver can tell whether the DF packets, in particular, got through.

 - Jonathan Morton