Download Full Version 300-620 Cisco Exam

This will ensure that the Quality of Service (QoS) levels and policies within the ACI fabric and the IPN devices match, preventing packets from being delayed or dropped between pods. Additionally, it is important to align the DSCP values of the packets with the configured QoS levels to ensure that the application's requirements for latency and jitter are met.

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 the VM controller to leaf node attachments.

The policy will be downloaded to leaf when you add host to the VMM switch. CDP/LLDP neighborship from host to leaf is required.

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.

With both immediate and on demand, if host and leaf lose LLDP/CDP neighborship the policies are removed.

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