See if DSCP is working

[darkman1983]

I've wondered if DSCP is actually working.
So i've used tcpdump to see, but that wasn't enough in my eyes, i needed a sneaky minimal GUI to see :-D

Setup:
SQM enabled in OMR for VPN + WAN -> DSCP FLAG's should be set. Is it required for VPN? Dunno :-P

So, DSCP is sent through VPN, which ones and do they arrive on VPS? Do they go out? Let's see...
OMR:

VPS (Interface with public IP):

I've also tested with WAN of OMR, but on that Interface (SQM enabled, DSCP should be set) only CS0 (Best Effort) goes out. Reading through internet revelad ISP is overriding or removing DSCP anyways.
But as DSCP is for specific ports most time and OMR sends portforwardings through VPN anyways, you can test.
The ISP is still a thing, because VPN traffic can't be prioritized.

As you can see, DSCP works, but there is a difference of what get's IN/OUT on OMR and VPS.

The Script (pure bash)

Requirement: tcpdump
Parameters: tun0 default or give interface name on script start
Setup: Install tcpdump if not installed. Save with desired name, eg. tos_counter.sh, chmod with eg. "ug+x", execute with eg. "./tos_counter".

NoPaste of Script

So, whats the conclusion of this?
Is DSCP worth using it?

Actually i don't know exactly, because of that difference of OMR / VPS on DSCP TOS flags...
Is there anything to be configured on VPS regarding DSCP? Only DEV of OMR can tell :-)

[darkman1983]

Script updated

[Ysurac]

DSCP give strange results on OMR, not exactly sure why.
VPS should always be higher than OMR as you are testing only tun0 on OMR, so only the VPN (it's not exactly the case, maybe some loss...). It's also possible that VPS output remove most of the DSCP tags.