we use Modular Quality of Service to classify and mark Voice and Video Conferencing Traffic.
VC and Voice use DSCP, IP-Prec and COS.
A sample of our network is...
On both routers we have "service-policy out" on the FrameRelay interface. We use the command "priority percent" for Voice and Video Conferencing, everything else uses the "bandwidth" command.
So from what I understand packets from VCS1 going to VCS2 will be sent out over the frame first, this is fine, packets from VCS2 going to VCS1 will also be sent out first.
But here's where I get confused, which isn't difficult :)...
The packets from VCS1 arrive on the router at the VCS2 end, does that router then need to have a "service-policy out" on the fast ethernet so that the packets get sent out first to the Layer3Switch?
Does the same apply to the Layer 3 switch (do I have to create the same service policy), or will simply trusting the DSCP values work on the router uplink interface and the VCS interface?
I'm happy with the way QoS works mainly and our configuration, the priority percent and bandwidth commands I know, I just can't seem to get my head around the way the router handles transiting traffic from a QoS perspective.