What is EndPoint Retention Policy in ACI?

 Endpoint Retention Policy:

--> Endpoint Retention Policy defines how long Endpoint information can be stored in the local endpoint table and remote endpoint table.

--> By default, The Local Endpoint table stores the endpoint information for 900 seconds, and the Remote Endpoint table stores the endpoint information for 300 Seconds.

--> This Endpoint Retention Policy is created by default in Common Tenant ( Tenant > Common > Policies > Protocol > Endpoint Retention)

--> All the Bridge Domains under the VRF will use this Endpoint Retention Policy which was created in Common Tenant.

--> We can have a different Endpoint Retention Policy per Bridge Domain in the VRF.

--> Following are the options we can configure in the Endpoint Retention Policy:

i) Local End Point Aging Interval:

--> Amount of time, The Leaf switch can store the directly connected Endpoint Information in the Local Endpoint Table

--> Default: 900 Seconds

--> If the Leaf Switch does not receive any packet within 675 seconds ( 75% of Local End Point Aging Interval) from any endpoint then Leaf Switch is going to generate three ARP Request Packets to the IP address of Local Endpoint.

--> If there is no response then the Endpoint Information is deleted from the Local Endpoint Table.

ii) Remote End Point Aging Interval:

--> Amount of time, The Leaf switch can store not directly connected Endpoint Information in the Remote Endpoint Table.

--> Default: 300 Seconds

--> If there is no traffic from the Remote Endpoint during 300 seconds then the Endpoint Information is deleted from the Remote Endpoint Table.

iii) Move Frequency:

--> The Maximum number of Endpoint moves allowed in the Bridge Domain.

--> Default : 256 Per Second

--> Endpoint Move is counted when the Endpoint flaps or Endpoint moves to another Leaf Switch.

--> If the number of Endpoint Moves( Both Local and Remote) crosses the Move Frequency in the Bridge Domain then the learning of endpoint is disabled in the BD until the hold timer expires.

--> Only the new Endpoint Information is not learned, The existing Endpoint Information will be retained in the Endpoint Table.

--> It is also called Endpoint Dampening.

iv) Hold timer

--> The amount of time Endpoint Learning is disabled in the Bridge Domain due to EP Loop or Endpoint Dampening.

--> Default: 300 Seconds

v) Bounce Entry Aging Interval

--> The amount of time in the Endpoint table for bouncing entry to expire

--> Default: 630 Seconds

Reference:

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