I read this passage in a QoS book I am reading and it left me a little confused:
Imagine a router is connected to a L2 switch via an access link, not a trunk, and that packets are being sent by the router to the switch port. What does it mean when it says in the book that "the switch will use the default value for untagged frames"?
If an ethernet frame does not have a dot1q tag (Im assuming this is what is meant by "untagged"), how can the switch mark the CoS setting? The 3 Cos bit positions that are part of the 2 byte VLAN tag are not available.