A.business-critical 
B.high priority 
C.middle class
D.voice
E.best effort
F.scavenger

A.end-to-end network delay times that exceed 50 ms for real-time traffic are considered unacceptable
B.end-to-end network delay times that exceed 250 ms for real-time traffic are considered unacceptable
C.end-to-end network delay is not a factor as long as the  delay is consistent
D.some packet loss can be corrected by codec algorithms
E.RSVP handles voice packet retransmission
F.fragmentation is a result of packet loss

A.analog trunks that provide the Survivable Remote Site Telephony (SRST) feature 
B.analog trunks that provide VoIP gateway functionality 
C.analog trunks that connect a gateway to plain old telephone service (POTS) device such as analog phones, fax machines, and legacy voice-mail systems  
D.analog trunks that connect a gateway to a central office (CO) or private branch exchange (PBX)

A.sampling
B.packetization
C.quantization
D.serialization

A.The router that is directly connected to the IP phone will look up the called number in its call routing table.
B.The router that is directly connected to the IP phone will inform its call agent when a service request is detected.
C.When the IP phone is picked up，the IP phone initiates the service request.
D.The directly connected router passes the collected digits to its call agent，and the call agent looks up in its call-routing table the called number.