多选题Which two statements are true about voice ports on a router？ （）ACalls to the PSTN can be made via the use of FXO or T1/E1 trunk ports.BCalls to the PSTN can be made via FXS or T1/E1 trunk ports.CAnalog and IP phones can be connected to the VoIP network

第1题：

Which two statements are true about voice packets in a LAN？ （Choose two.）  （）

• A、 Voice traffic data flow involves large volumes of large packets.
• B、 Because a packet loss involves a small amount of data， voice traffic is less affected by packet losses than traditional data traffic is.
• C、 Voice carrier stream utilizes Real-Time Transport Protocol （RTP） to carry the audio/media portion of VoIP communication.
• D、 Voice packets are very sensitive to delay and jitter.
• E、 Voice packets are encapsulated in TCP segments to allow for proper sequencing during delivery.

第2题：

Which two statements are true about Voice over IP （VoIP） packet delivery in a digital infrastructure？ （）

• A、 Packets can arrive out of order.
• B、 Packets must take the same path to the destination.
• C、 Once packets are received at the destination router， the router performs sampling to ensure the quality of the voice traffic.
• D、 Packets can experience varying delays across the network.
• E、 Packets containing voice samples are sequentially numbered by default， allowing for reordering upon arrival at the terminal router along the path.

第3题：

Which statements is true about Foreign Exchange Station （FXS） ports on a router？（）

• A、the FXS interface allows an analog connection to be directed at the public switched telephone network （PSTN’s） central office
• B、the FXS interface connect directly to a standard telephone， fax machine， or sililar device and supplies ring， voltage， and dial tone
• C、the FXS interface connect directly to an IP phone and supplies ring， voltage， and dial tone
• D、the FXS interface connect directly to ISDN voice channels

第4题：

Which two statements are true about L2TP tunnels?（） (Choose two.)

• A、Traffic is clear text
• B、Traffic is encrypted 
• C、They are initiated by the LNS
• D、They are initiated by the LAC

第5题：

Which two statements are true about the role of split horizon？（）

• A、It is a function used by routing protocols to install routes into routing table
• B、It is a function that prevents the advertising of routes over an interface that the router is usingto reach a route
• C、Its function is to help avoid routing loops.
• D、It is a redistribution technique used by routing protocols

第6题：

Which two statements are true about the function of CAC？（）

• A、CAC provides guaranteed voice quality on a link.
• B、CAC artificially limits the number of concurrent voice calls.
• C、CAC is used to control the amount of bandwidth that is taken by a call on a link.
• D、CAC prevents oversubscription of WAN resources that is caused by too much voice traffic.
• E、CAC allows an unlimited number of voice calls while severely restricting，if necessary，other forms of traffic.
• F、CAC solves voice congestion problems by using QoS to give priority to UDP traffic.

第7题：

Which two statements are true about the protocols that are used for transmitting voice traffic？（）

• A、RTP multiplexing is used to keep multiple phone conversations separate
• B、RTP provides end-to-end delivery services for voice traffic.
• C、UDP is used to ensure a reliable transmission from sender to receiver.
• D、RTP is used to provide resource reservation for the voice stream.
• E、UDP provides multiplexing of multiple phone conversations.

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第13题：

Which two statements are true about the protocols that are used for transmitting voice traffic？（）

• A、RTP multiplexing is used to keep multiple phone conversations separate
• B、RTP provides end-to-end delivery services for voice traffic
• C、UDP is used to ensure a reliable transmission from sender to receiver
• D、RTP is used to provide resource reservation for the voice stream
• E、UDP provides multiplexing

第14题：

Which two statements are true about voice VLANs？（）

• A、Voice VLANs are only used when connecting an IP phone and a host to distinct switch ports
• B、Access ports that are configured with voice VLANs will always trust the CoS that is received from IP phones
• C、Access ports that are configured with voice VLANs may or may not override the CoS value that is received from an IP phone
• D、Voice VLANs are configured using the switchport voice vlan vlan-ID interface configuration command
• E、Voice VLANs provide a trunking interface between an IP phone and an access port on a switch to allow traffic from multiple devices that are connected to the port
• F、Enabling Voice VLAN on a switch port will automatically configure the port to trust the incoming CoS markings

第15题：

Router R1 and R2 are both configured for HSRP.  Which two statements about the HSRP priorities  of these two routers are true？（）

• A、 To assign the HSRP router priority in a standby group， the standby group-number priority  priority-value global configuration command must be used.
• B、 The default priority of a router is zero （0）.
• C、 The no standby priority command assigns a priority of 100 to the router.
• D、 Assuming that preempting has also been configured， the router with the lowest priority in an  HSRP group would become the active router.
• E、 When two routers in an HSRP standby group are configured with identical priorities， the router  with the highest configured IP address will become the active router.

第16题：

Which two statements are true about the configuration of voice VLANs？（）

• A、Static secure MAC addresses can be configured in conjunction with voice VLANs.
• B、PortFast is automatically enabled when voice VLANs are configured.
• C、PortFast must be manually configured when voice VLANs are configured.
• D、Voice VLANs are typically configured on uplink ports.
• E、Voice VLANs are typically configured on access ports.

第17题：

Which two statements are true about network voice traffic？ （Choose two.）（）

• A、 Voice traffic is affected more by link speed than FTP traffic is.
• B、 Voice traffic is affected more by packet delays than FTP traffic is.
• C、 Voice streams involve larger packet sizes than most TCP network traffic involves.
• D、 Voice traffic is more sensitive to packet loss than TCP network traffic is.
• E、 Voice traffic requires QOS mechanisms only in heavily loaded network segments.

第18题：

Which of the following statements is true about a router's eBGP peers that is not  also true about that same router's iBGP peers?（）

• A、The eBGP peer neighborship uses TCP
• B、The eBGP peer uses port 180 (default)
• C、The eBGP peer uses the same ASN as the local router
• D、The eBGP peer updates its AS_Path PA before sending updates to  this router

第19题：

Which two statements are true about precedence values in policy?（） (Choose two.)

• A、1 is the default precedence.
• B、A lower number is preferred.
• C、A higher number is preferred.
• D、100 is the default precedence.

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