Re: [Dart] RTP and non-RTP traffic on same UDP 5-tuple

[Harald Alvestrand <[e-mail]>]

On 06/12/2014 03:46 AM, Brian E Carpenter wrote:
> On 12/06/2014 12:58, Black, David wrote:
>>> What do you mean by 'all the packets would be classified the same'?  If you
>>> mean all the packets in a 5-tuple would get the same differentiated treatment,
>>> that is not desirable, because there are lots of folks wanting to send video
>>> i-frames or packets with FEC or other stuff with lower drop precedence than
>>> other packets.
>> That would most likely be within an AF class; the entire set of packets marked
>> w/different drop precedences within an AF class should be classified the same.
>>
>> Beyond that, one can hope that any AF remarker (e.g., for traffic shaping) is
>> running in Color-Aware mode and hence tries to preserve source drop precedence
>> distinctions, but this cannot be relied upon.
> Indeed not, and that's on the assumption that the receiving domain
> even operates an AF service class. The worst case assumption is
> that everything reverts to best effort somewhere along the path.

That's a fairly benign case, actually.
The worst case is that DSCP priorities get remapped in a way that 
inverts drop precedence (see the draft's discussion about 
less-than-best-effort).

I hope that's not a case that's so frequent that we have to worry 
over-much about it.