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

[Mark Tinka]

On 2/Oct/18 12:21, Julien Goodwin wrote:

> 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.

This.

And you've reminded me, Julien. In our case, we had 2 issues; one where
the customer's firewall was doing strange things to non-zero DSCP value,
and a second where a customer ISP network was doing strange things to
non-zero DSCP values, because of the way they needed to handle all
traffic that had that DSCP value in a locally-significant manner.

Mark.