Cisco CCNP Enterprise 350-401 Questions & Answers

• Question 281:

  Refer to the exhibit.

  

  Which network script automation option or tool is used in the exhibit?

  A. EEM

  B. Bash script

  C. REST correct

  D. NETCONF

  E. Python

  Correct Answer: C

• Question 282:

  Which data modeling language is commonly used by NETCONF?

  A. REST

  B. YANG

  C. HTML

  D. XML

  Correct Answer: B

  Cisco IOS XE supports the Yet Another Next Generation (YANG) data modeling language. YANG can be used with the Network Configuration Protocol (NETCONF) to provide the desired solution of automated and programmable network operations. NETCONF(RFC6241) is an XML-based protocol that client applications use to request information from and make configuration changes to the device. YANG is primarily used to model the configuration and state data used by NETCONF operations. Reference: https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9500/software/release/1 6-5/ configuration_guide/prog/b_165_prog_9500_cg/data_models.pdf

• Question 283:

  Which variable in an EEM applet is set when you use the sync yes option?

  A. $_cli_result

  B. $_exit_status

  C. $_string_result

  D. $_result

  Correct Answer: B

  With Synchronous ( sync yes), the CLI command in question is not executed until the policy exits. Whether or not the command runs depends on the value for the variable _exit_status. If _exit_status is 1, the command runs, if it is 0, the command is skipped.

• Question 284:

  A GRE tunnel is down with the error message %TUN-5-RECUR DOWN:

  

  Which two options describe possible causes of the error? (Choose two)

  A. There is link flapping on the tunnel

  B. Incorrect destination IP addresses are configured on the tunnel

  C. The tunnel mode and tunnel IP address are misconfigured

  D. There is instability in the network due to route flapping

  E. The tunnel destination is being routed out of the tunnel interface

  Correct Answer: DE

  The %TUN-5-RECURDOWN: Tunnel0 temporarily disabled due to recursive routing error message means that the generic routing encapsulation (GRE) tunnel router has discovered a recursive routing problem. This condition is usually due to one of these causes:

  + A misconfiguration that causes the router to try to route to the tunnel destination address using the tunnel interface itself (recursive routing) + A temporary instability caused by route flapping elsewhere in the network Reference: https:// www.cisco.com/c/en/us/support/docs/ip/enhanced-interior-gateway- routingprotocol- eigrp/22327-gre-flap.html

• Question 285:

  Which two statements about HSRP are true? (Choose two)

  A. It supports unique virtual MAC addresses

  B. Its virtual MAC is 0000.0C07.ACxx

  C. Its default configuration allows for pre-emption

  D. It supports tracking

  E. Its multicast virtual MAC is 0000.5E00.01xx

  Correct Answer: BD

• Question 286:

  What are three valid HSRP states? (Choose three)

  A. INIT

  B. listen

  C. full

  D. learning

  E. speak

  F. established

  Correct Answer: ABE

  HSRP StatesWhen in operation, HSRP devices are configured into one of many states:

  Active ?This is the state of the device that is actively forwarding traffic.

  Init or Disabled ?This is the state of a device that is not yet ready or able to participate in HSRP.

  Learn ?This is the state of a device that has not yet determined the virtual IP address and has not yet seen a hello message from an active device.

  Listen ?This is the state of a device that is receiving hello messages.

  Speak ?This is the state of a device that is sending and receiving hello messages.

  Standby ?This is the state of a device that is prepared to take over the traffic forwarding duties from the active device.

• Question 287:

  Which two statements about IP SLA are true? (Choose two)

  A. It uses NetFlow for passive traffic monitoring

  B. It can measure MOS

  C. The IP SLA responder is a component in the source Cisco device

  D. It is Layer 2 transport-independent correct

  E. It uses active traffic monitoring correct

  F. SNMP access is not supported

  Correct Answer: DE

  IP SLAs allows Cisco customers to analyze IP service levels for IP applications and services, to increase productivity, to lower operational costs, and to reduce the frequency of network outages. IP SLAs uses active traffic monitoringhe generation of traffic in a continuous, reliable, and predictable manneror measuring network performance. Being Layer-2 transport independent, IP SLAs can be configured end-to- end over disparate networks to best reflect the metrics that an end-user is likely to experience. Reference: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipsla/configuration/15-mt/sla-15- mt-book/ sla_overview.html

• Question 288:

  Which QoS mechanism will prevent a decrease in TCP performance?

  A. Shaper

  B. Rate-Limit

  C. Policer

  D. Fair-Queue

  E. WRED

  F. LLQ

  Correct Answer: E

  Weighted Random Early Detection (WRED) is just a congestion avoidance mechanism. WRED drops packets selectively based on IP precedence. Edge routers assign IP precedences to packets as they enter the network. When a packet

  arrives, the following events occur:

  The average queue size is calculated.

  2.

  If the average is less than the minimum queue threshold, the arriving packet is queued.

  3.

  If the average is between the minimum queue threshold for that type of traffic and the maximum threshold for the interface, the packet is either dropped or queued, depending on the packet drop probability for that type of traffic.

  4.

  If the average queue size is greater than the maximum threshold, the packet is dropped. WRED reduces the chances of tail drop (when the queue is full, the packet is dropped) by selectively dropping packets when the output interface begins to show signs of congestion (thus it can mitigate congestion by preventing the queue from filling up). By dropping some packets early rather than waiting until the queue is full, WRED avoids dropping large numbers of packets at once and minimizes the chances of global synchronization. Thus, WRED allows the transmission line to be used fully at all times. WRED generally drops packets selectively based on IP precedence. Packets with a higher IP precedence are less likely to be dropped than packets with a lower precedence. Thus, the higher the priority of a packet, the higher the probability that the packet will be delivered. Reference: https://www.cisco.com/c/en/ us/td/docs/ios-xml/ios/qos_conavd/ configuration/15- mt/qos-conavd-15-mt-book/qos-conavd-cfg-wred.html WRED is only useful when the bulk of the traffic is TCP/IP traffic. With TCP, dropped packets indicate congestion, so the packet source will reduce its transmission rate. With other protocols, packet sources may not respond or may resend dropped packets at the same rate. Thus, dropping packets does not decrease congestion. Reference: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/qos_conavd/ configuration/xe- 16/qos- conavd-xe-16-book/qos-conavd-oview.html Note: Global synchronization occurs when multiple TCP hosts reduce their transmission rates in response to congestion. But when congestion is reduced, TCP hosts try to increase their transmission rates again simultaneously (known as slow-start algorithm), which causes another congestion. Global synchronization produces this graph:

  

• Question 289:

  Which statement about the default QoS configuration on a Cisco switch is true?

  A. The Cos value of each tagged packet is modified

  B. Port trust is enabled

  C. The Port Cos value is 0

  D. All traffic is sent through four egress queues

  Correct Answer: C

• Question 290:

  How are the Cisco Express Forwarding table and the FIB related to each other?

  A. Cisco Express Forwarding uses a FIB to make IP destination prefix-based switching decisions correct

  B. The FIB is used to populate the Cisco Express Forwarding table

  C. There can be only one FIB but multiple Cisco Express Forwarding tables on IOS devices

  D. The Cisco Express Forwarding table allows route lookups to be forwarded to the route processor for processing before they are sent to the FIB

  Correct Answer: A

  The Forwarding Information Base (FIB) table ?CEF uses a FIB to make IP destination prefix-based switching decisions. The FIB is conceptually similar to a routing table or information base. It maintains a mirror image of the forwarding information contained in the IP routing table. When routing or topology changes occur in the network, the IP routing table is updated, and these changes are reflected in the FIB. The FIB maintains next-hop address information based on the information in the IP routing table. Reference: https://www.cisco.com/c/en/us/support/docs/routers/12000-series-routers/47321- ciscoef.html