Have a bit of a problem qos related. Network Topology is below...
We have an Avaya PBX connected to a 3750 switch , it throws out packets with a diffserv setting of Expedited forwarding -- which is what we want.
Our phones are located a few trunks away , and when we do an ethereal trace here , it appears that the diffserv setting of the original packet from the PBX is gone -- its is now on default diffserv.
We dont really have any qos set up at all , so any advice as to the best way to prioritise vlan 300 and keep the diffserv tag of the pbx preserved across network would be appreciated.
and see how CoS to DSCP can work for you across the switches