A.The access layer is the initial point at which traffic enters the network. Traffic is marked （orremarked） at Layers 2 and 3 by the access switch as it enters the network， or is "trusted" that it isentering the network with the appropriate tag
B.No traffic marking occurs at the core layer. Layer 2/3 QoS tags are trusted from distributionlayer switches and used to prioritize and queue the traffic as it traverses the core
C.Traffic inbound from the access layer to the distribution layer can be trusted or reset dependingupon the ability of the access layer switches. Priority access into the core is provided based onLayer 3 QoS tags
D.IP precedence， DSCP， QoS group， IP address， and ingress interface are Layer 2 characteristics that are set by the access layer as it passes traffic to the distribution layer. Thedistribution layer， once it has made a switching decision to the core layer， strips these off
E.MAC address， Multiprotocol Label Switching （MPLS）； the ATM cell loss priority （CLP） bit， theFrame Relay discard eligible （DE） bit， and ingress interface are established by the voicesubmodule （distribution layer） as traffic passes to the core layer
F.The distribution layer inspects a frame to see if it has exceeded a predefined rate of trafficwithin a certain time frame， which is typically a fixed number internal to the switch. If a frame isdetermined to be in excess of the predefined rate limit， the CoS value can be marked up in a waythat results in the packet being dropped

A.QoS classified at layer 3 using IP precedence or DSCP
B.Guaranteed rate service
C.Implemented using FIFO queues
D.All traffic has an equal chance of being dropped

A.Quality of Service （QoS）
B.Intelligent platforms
C.Mobility and scalability
D.Security
E.High availability

A.The use of a queuing method that will give VoIP traffic strict priority over other traffic
B.The use of RTP header compression for the VoIP traffic
C.The proper classification and marking of the traffic as close to the source as possible
D.The use of 802.1QinQ trunking for VoIP traffic
E.The use of WRED

A.IP phones require inline power and must be in separate VLAN to receive inline power
B.IP telephony applications require prioritization over other traffic as they are more delaysensitive
C.IP phones can only receive IP addresses through DHCP if they are in separate VLAN
D.The CDP frames from the IP phone can only be recognized by the switch if the phone is in anauxiliary vlan