Endpoint Learning in ACI

Endpoint Learning in ACI 

An endpoint consists of one MAC address and zero or more IP addresses. Each endpoint represents a single networking device.

Cisco ACI replaced the MAC address table and ARP table with a single table called the endpoint table. This change implies that Cisco ACI learns that information in a different way than in a traditional network. Cisco ACI learns MAC and IP addresses in hardware by looking at the packet source MAC address and source IP address in the data plane instead of relying on ARP to obtain a next-hop MAC address for IP addresses.

It also allows detection of IP address and MAC address movement without the need to wait for GARP as long as some traffic is sent from the new host. Although Cisco ACI uses the endpoint table instead of the MAC address and ARP tables, it still uses the RIB and the ARP table (for L3Out).

A leaf switch has two types of endpoints:

• Local endpoints

• Remote endpoints

Local endpoints are the main source of endpoint information for the entire Cisco ACI fabric. Each leaf is responsible for reporting its local endpoints to the Council Of Oracle Protocol, which is known as COOP, database, located on each spine switch. Spine switch stores these endpoints in the COOP database and synchronizes with other spine switches.

When leaf switch does not know the destination endpoint, leaf can forward packet to spine switch to let spine switch decide where to send. This forwarding behavior is called spine proxy.