Exam 300-620 topic 1 question 237 discussion

To meet the requirements where contracts are pushed to the Cisco ACI leaf switches when a VM is mapped to an EPG and removed when LLDP is disabled, the following configuration must be selected: Configuration Option: On-Demand Resolution for VMM Domain

C is correct

B. Resolution immediacy: On-Demand This will ensure that contracts are only applied and enforced when the endpoints (VMs) are actually discovered and present, and they are removed when LLDP is disabled, reflecting the dynamic presence or absence of the endpoints.

deployment immediacy is when policy is written to the CAM.

Swaying towards B as the answer - https://learnduty.com/cisco-aci/cisco-aci-resolution-and-deployment-immediacy-explained/

On Demand: VLAN will be deployed on leaf interfaces only when: 1- Hosts are detected via LLDP/CD (basically immediate) 2- At least one VM is associated to the EPG corresponding port group.

Answer is B: • On Demand—Specifies that a policy (for example, VLAN, VXLAN bindings, contracts, or filters) is pushed to the leaf node only when an ESXi host is attached to a DVS and a VM is placed in the port group (EPG). The policy will be downloaded to leaf when host is added to VMM switch and virtual machine needs to be placed into port group (EPG). CDP/LLDP neighborship from host to leaf is required.

Immediate—Specifies that EPG policies (including contracts and filters) are downloaded to the associated leaf switch software upon ESXi host attachment to a DVS. LLDP or OpFlex permissions are used to resolve Immediate—Specifies that the policy is programmed in the hardware policy CAM as soon as the policy is downloaded in the leaf software. On Demand—Specifies that a policy (for example, VLAN, VXLAN bindings, contracts, or filters) is pushed to the leaf node only when an ESXi host is attached to a DVS and a VM is placed in the port group (EPG). Pre-provision—Specifies that a policy is downloaded to a leaf switch even before a VM controller is attached to the virtual switch . This pre-provisions the configuration on the switch. 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_01011.html