Which three statements are true about the data traffic chara

第1题：

Which three statements are true about the data traffic characteristics of voice traffic？ （）

• A、latency must be kept below 150 ms
• B、latency is not a concern as long as jitter is kept below 30 ms
• C、voice packets do not require a specific type of queuing
• D、voice packets are rather small
• E、voice packets require TCP for rapid retransmission of dropped packets
• F、voice packets require a fairly constant bandwidth reserved for voice control traffic as well as forthe voice payload

第2题：

In relation to MPLS Multicast VPN， which three statements about multicast distribution （MDT） groups aretrue？ （）

• A、Default MDT groups are used for PIM control traffic， low-bandwidth sources， and flooding of sparse mode traffic.
• B、MDTs are built in customer networks
• C、Data MDT groups are used for high-bandwidth sources to reduce replication to uninterested PEs.
• D、MDTs are built in provider networks
• E、The number of MDTs depends on PIM modes of MDT groups.

第3题：

第4题：

Which three statements are true about the voice VLAN feature on a Catalyst 2950 switch？ （Choose  three.）（）  

• A、 The CoS value is trusted for 802.1p or 802.1q tagged traffic.
• B、 The voice VLAN feature is disabled by default.
• C、 The IP phone accepts the priority of all tagged and untagged traffic and sets the CoS value to 4.
• D、 When the voice VLAN feature is enabled， all untagged traffic is sent according to the default CoS priority of the port.
• E、 PortFast is automatically disabled when a voice VLAN is configured.
• F、 The default CoS value for incoming traffic is set to 0.

第5题：

VOIP has been implemented at the main office of the Company network. Which two statements  are true about voice packets in a LAN？（）

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

第6题：

Which three statements about bidirectional PIM are true？（）

• A、Traffic for a bidirectional group flows along the one shared tree and simultaneously utilizes multiple paths in a redundant network topology
• B、It does not require any traffic signaling in the protocol
• C、Membership to a bidirectional group is signaled using explicit Join messages
• D、It maintains source-specific forwarding state
• E、It reduces memory， bandwidth， and CPU requirements

第7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8题：

第9题：

Which statement is true about the data traffic between the access point named TKAP1 and  controller TKC1？（）

• A、 The data traffic between the access point and controller is not encrypted.
• B、 The data traffic is encapsulated with LWAPP.
• C、 The data traffic is switched at the access point before being sent to the WLAN controller where  VLAN tagging and QoS are applied.
• D、 The data traffic is encrypted with AES.
• E、 All of the above

第10题：

Which statement is true about voice VLANs？ （）

• A、When the voice VLAN feature is enabled， all untagged voice and data traffic is sent through the voice VLAN.
• B、The voice VLAN feature is enabled by default.
• C、The IP phone overrides the priority of all incoming data traffic （tagged and untagged） and sets the CoS value to 0.
• D、The default CoS value is 1 for incoming voice and data traffic.