Which two functions can be provided by an Integrated Services Router （ISR） in a VoIP network？（）

A. Channel-associated signaling transmits control signals in band and therefore reduces the bandwidth available for the voice data stream.
B. Channel-associated signaling utilizes a separate TDM channel for transmitting control signals.
C. Common channel signaling transmits control signals in band and therefore reduces the bandwidth available for the voice data stream.
D. Common channel signaling uses one of the TDM channels to transmit control information reducing the number of channels available for voice.
E. ISDN BRIs implement channel-associated signaling.

A. Analog phones， connected to the PSTN， act as internal call agents if IP communication to the CallManager is lost.
B. An onsite gateway reroutes calls over the PSTN if IP communication to the CallManager is lost.
C. The IP phones can reroute calls over the PSTN if IP communication to the CallManager is lost.
D. Local voice gateways can assume the function of a call agent if IP communication to the CallManager is lost.
E. IP phones use an internal call agent if IP communication to the CallManager is lost.

A. Call Management Link Agent
B. Traffic policing
C. Call Admission Control
D. QoS Link Congestion Management
E. Oversubscription Link Detection