问题：

[多选]

You need to determine where the trust boundaries will be in a new Company VOIP design. 
Which  two statements are true about these trust boundaries？（）

A . Trust boundaries are configured in the core of the network to provide the most efficient  forwarding based upon QoS markings，
B . Setting trust boundaries at the edge of the network allows intermediate hop devices to  administer QoS policies without detailed packet identification.
C . Trust boundaries are used to determine which QoS mechanism will be applied to the traffic.  
D . At the trust boundaries， the untrusted traffic will be marked with a new QoS value appropriate  for the policy in place at the point where the traffic entered the campus network.  
E . Trust boundaries define the firewall rules for QoS admission into a network.