Cisco CCNP Data Center 300-620 Questions & Answers

• Question 191:

  An engineer must ensure that Cisco ACI flushes the appropriate endpoints when a topology change notification message is received in an MST domain. Which three steps are required to accomplish this goal? (Choose three.)

  A. Enable the BPDU interface controls under the spanning tree interface policy.

  B. Configure a new STP interface policy.

  C. Bind the spanning tree policy to the switch policy group.

  D. Associate the STP interface policy to the appropriate interface policy group.

  E. Create a new region policy under the spanning tree policy.

  F. Map VLAN range to MST instance number.

  Correct Answer: CEF

  https://learnduty.com/cisco-aci/cisco-aci-and-mst-interaction/

• Question 192:

  Refer to the exhibit.

  

  A systems engineer is implementing the Cisco ACI fabric. However, the Server2 information is missing from the Leaf 101 endpoint table and the COOP database of the spine. The requirement is for the bridge domain configuration to enforce the ACI fabric to forward the unicast packets generated by Server1 destined to Server2. Which action must be taken to meet these requirements?

  A. Enable ARP Flooding

  B. Set L2 Unknown Unicast to Flood

  C. Set IP Data-Plane Learning to No

  D. Enable Unicast Routing

  Correct Answer: B

• Question 193:

  What happens to the traffic flow when the Cisco ACI fabric has a stale endpoint entry for the destination endpoint?

  A. The leaf switch does not learn the source endpoint through data plane learning.

  B. The leaf switch drops the traffic that is destined to the endpoint.

  C. The leaf switch floods the traffic to the endpoint throughout the fabric.

  D. The leaf switch sends the traffic to the wrong destination leaf.

  Correct Answer: D

  Because of this stale remote endpoint, any traffic from LEAF1 toward IP2 will fail, because LEAF1 sends packets to the wrong leaf.

  This stale remote endpoint on LEAF1 needs to be manually cleared to resume communication. The command syntax to manually clear a particular remote IP endpoint is shown here:

  LEAF1# clear system internal epm endpoint key vrf ip

  Reference:

  https://www.ciscolive.com/c/dam/r/ciscolive/us/docs/2019/pdf/BRKACI-2641.pdf

• Question 194:

  Which method does the Cisco ACI fabric use to load-balance multidestination traffic?

  A. forwarding tag trees

  B. PIM routing

  C. spanning trees

  D. shortest-path trees

  Correct Answer: A

  Reference: https://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/1-x/aci-fundamentals/b_ACI-Fundamentals/b_ACI-Fundamentals_chapter_010010.html

• Question 195:

  When the subnet is configured on a bridge domain, on which physical devices is the gateway IP address configured?

  

  A. all leaf switches and all spine nodes

  B. only spine switches where the bridge domain of the tenant is present

  C. only leaf switches where the bridge domain of the tenant is present

  D. all border leaf nodes where the bridge domain of the tenant is present

  Correct Answer: C

  Reference: http://www.netdesignarena.com/index.php/2016/06/16/aci-tenant-building-blocks-forwarding-logic/

• Question 196:

  An engineer configured a bridge domain with the hardware-proxy option for Layer 2 unknown unicast traffic. What occurs in this configuration?

  A. The leaf switch drops the Layer 2 unknown unicast packet if it is unable to find the MAC address in the local forwarding tables.

  B. The Layer 2 unknown hardware proxy lacks support of the topology change notification.

  C. The leaf switch forwards the Layers 2 unknown unicast packets to all other leaf switches if it is unable to find the MAC address in its local forwarding tables.

  D. The spine switch drops the Layer 2 unknown unicast packet if it is unable to find the MAC address in the COOP database.

  Correct Answer: D

  When using hardware-proxy, you should consider enabling unicast routing and defining a subnet on the bridge domain. This is because with hardware-proxy on, if a MAC address has been aged out in the spine switch-proxy, traffic destined to this MAC address is dropped. Reference: https://www.cisco.com/c/en/us/td/docs/dcn/whitepapers/cisco-application-centric-infrastructure-design-guide.html#Usinghardwareproxytoreduceflooding

• Question 197:

  An engineer configured Layer 2 extension from the ACI fabric and changed the Layer 2 unknown unicast policy from Flood to Hardware Proxy. How does this change affect the flooding of the L2 unknown unicast traffic?

  A. It is forwarded to one of the spines to perform as a spine proxy.

  B. It is flooded within the whole fabric.

  C. It is dropped by the leaf when the destination endpoint is not present in the endpoint table.

  D. It is forwarded to one of the APICs to perform as a proxy.

  Correct Answer: A

  Reference:

  https://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/2-x/L2_config/b_Cisco_APIC_Layer_2_Configuration_Guide/ b_Cisco_APIC_Layer_2_Configuration_Guide_chapter_010.html

• Question 198:

  What must be enabled in the bridge domain to have the endpoint table learn the IP addresses of endpoints?

  A. L2 unknown unicast: flood

  B. GARP based detection

  C. unicast routing

  D. subnet scope

  Correct Answer: C

• Question 199:

  An engineer is extending EPG connectivity to an external network. The external network houses the Layer 3 gateway and other end hosts. Which ACI bridge domain configuration should be used?

  A. Forwarding: Custom L2 Unknown Unicast: Hardware Proxy L3 Unknown Multicast Flooding: Flood Multi Destination Flooding: Flood in BD ARP Flooding: Enabled

  B. Forwarding: Custom L2 Unknown Unicast: Flood L3 Unknown Multicast Flooding: Flood Multi Destination Flooding: Flood in BD ARP Flooding: Enabled

  C. Forwarding: Custom L2 Unknown Unicast: Hardware Proxy L3 Unknown Multicast Flooding: Flood Multi Destination Flooding: Flood in BD ARP Flooding: Disabled

  D. Forwarding: Custom L2 Unknown Unicast: Flood L3 Unknown Multicast Flooding: Flood Multi Destination Flooding: Flood in BD ARP Flooding: Disabled

  Correct Answer: B

• Question 200:

  Which endpoint learning operation is completed on the ingress leaf switch when traffic is received from a Layer 3 Out?

  A. The source MAC address of the traffic is learned as a local endpoint.

  B. The source MAC address of the traffic is learned as a remote endpoint.

  C. The source IP address of the traffic is learned as a remote endpoint.

  D. The source IP address of the traffic is learned as a local endpoint.

  Correct Answer: A

  Local endpoint learning with an incoming packet from L3Out to Cisco ACI:

  Only the source MAC address is learned as a local endpoint. The source IP address is not learned as a local endpoint.

  Scenario 2

  Remote endpoint learning with an incoming packet from L3Out to Cisco ACI:

  No source MAC or IP address is learned as a new remote endpoint by a packet.*

  https://www.cisco.com/c/en/us/solutions/collateral/data-center-virtualization/application-centric-infrastructure/white-paper-c11-739989.html