多项选择题

Which three practices are important to the implementation of a DiffServ QoS architecture？（）

A. Because services are allocated throughout the network before the transmission of data begins， traffic classes can be guaranteed QoS services.
B. Traffic classes are marked with Layer 2 markings to allow for more granularity in identifying traffic classes.
C. Traffic classes are marked with Layer 3 markings to allow them to traverse different network types without loss of QoS information.
D. Traffic classes allow networks to provide proper QoS treatment of packets without applications having to request services.
E. Based upon the network capabilities， QoS markings are placed on packets as needed throughout the network to allow for proper QoS treatment of packets.
F. QoS markings are placed on packets as close to the network edge as possible to allow distribution and core devices to determine QoS actions as quickly as possible.

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多项选择题

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

A. ISR can perform the functions of a multipoint control unit to facilitate voice conferencing.
B. ISR can perform the function of a call agent in the event of loss of communication with a CallManager.
C. ISR can provide XML applications to the phones.
D. ISR can provide all of the functionality of a CallManager in the event of loss ofcommunication to the CallManager.
E. ISR can act as a voice gateway to the PSTN.

多项选择题

Which two statements are correct about the signaling methods that are utilized for transmitting voice？（）

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.

多项选择题

Which two VoIP capabilities are utilized when the CallManager and the gateway are configured for Survivable Remote Site Telephony？（）

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.