What is Endpoint Learning in ACI?

 Endpoint Learning in ACI

--> In traditional Networks, We use three tables to maintain the network information about all the devices.

i) MAC Address table: used when we have two devices that need to communicate within the same network

ii) RIB( Routing Table): Used when we have two devices that need to communicate between two different networks.

iii) ARP Table: Used to provide the relationship between IP address and MAC address

--> In ACI Network, We also use three tables to maintain the network information about all the devices.

i) Endpoint Table:

--> Used when we have two devices that need to communicate within the ACI network regardless of the subnet.

--> Endpoint table contains the IP and MAC address of Every Device that is connected to ACI Fabric.

--> Endpoint IP stored in the table will be either /32 or /128 only.

2) RIB Table:

--> Used when we have one device in ACI want to communicate to the device that is present outside of ACI Fabric (WAN/Internet).

--> RIB Table contains the Network Information with the Next Hop IP address to forward the traffic.

--> Network Information in RIB Table will be Non /32 or Non /128 only.

--> All the SVI ( BD Subnet Address), Routed Ports, Sub Interface IP addresses are stored in RIB Table.

3) ARP Table:

--> Used to get the MAC address of the device that is outside of the ACI Fabric ( L3Out Connections).

Endpoint Learning:

1) Local Endpoint : 

--> Local Endpoint is the Endpoint that is connected locally to the leaf switch.

--> Every Leaf Switch announces the local Endpoints ( Endpoints are connected locally to the leaf switch) to the spine switch through COOP Protocol.

--> That means the spine switches in the ACI Fabric contains all the local Endpoint information in its COOP database.

--> Whenever the Leaf Switch does not know the Endpoint in the ACI, It simply asks the Spine to get the information about the endpoint which is not connected locally to the switch.

--> This behavior is called a Spine Proxy.

--> Stores the Local Endpoint Information for 900 seconds.

2) Remote Endpoint: 

--> Remote Endpoint is the Endpoint that is connected remotely to the leaf switch ( Connected to another leaf switch).

--> Stores the Remote Endpoint Information for 300 seconds.

--> Remote Endpoint Information is deleted from the table if there is no activity for 300 seconds.

Reference:

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