Hi all! I´m Juan from Argentina.
I´m studying for my CCIE WR exam, and i have 3 questions.
Topology
PC - IP Phone - SW L2 - Trunk to another L3 SW (here there are all the interface vlans) - SW L3 trunk to Router - Router connected to WAN MPLS.
In the connection between IP Phone and L2 SW, i have configured "mls qos trust cos", to trust in the CoS field of ip phone.
My questions are:
1- In the trunk between L2 and L3 switch. What kind of configuration must i use? Must I trust in DSCP or CoS field? What command type I must use? Trust dscp or cos., or both.
2- In the trunk between L3 and Router. What kind of configuration must i use?? What command type I must use? Trust dscp or cos, or both
3- When a L3 Switch send a frame (after dscp-cos table), does the switch utilize CoS field in the egress frame?
Sorry by my english
Best Regards
Juan
