[j-nsp] Use cases for IntServ in MPLS backbones

[Julien Goodwin]

On 02/10/18 20:10, Saku Ytti wrote:
> Hey Mark,
> 
>> We remark all incoming Internet traffic DSCP values to 0.
>>
>> A few years ago, not doing this led to issues where customers were handling the DSCP values in such a way that any traffic marked as such was being dropped. Took weeks to troubleshoot.
> 
> Dropped by who? I as an Internet user would prefer my DSCP information
> to traverse internet, I do not ask it to be honoured.

The trouble is, some providers might use a bit to mean something like
"prefer cheap EU paths" for Asia->AU traffic, leaving it set then causes
hundreds of milliseconds of latency. Some might even implement VPNs that
way causing blackholing.

We had a few cases where failing to set DSCP to zero at our edge (in
either direction) caused various issues, those also took weeks to
troubleshoot.