Exam 300-620 topic 1 question 284 discussion

It is A. In a Cisco ACI fabric with vPC configured between two leaf switches (Leaf1 and Leaf2), when a server (S1) is connected to one of the leaf switches (e.g., Leaf1), the endpoint learning process works as follows: Local Endpoint Learning on Leaf1: Since S1 is directly connected to Leaf1, its MAC and IP addresses are learned as local endpoints on Leaf1. Remote Endpoint Learning on Leaf2: In a vPC configuration, the two leaf switches (Leaf1 and Leaf2) operate as vPC peers but do not share a dedicated peer link. Instead, the ACI fabric itself acts as the medium for communication between the peers. Leaf1 communicates the endpoint information (MAC and IP of S1) to the spine switches using the COOP (Council of Oracle Protocol) database. The spine then propagates this information to Leaf2. On Leaf2, S1 is learned as a remote endpoint because it is not directly connected to Leaf2 but is reachable through its vPC peer (Leaf1).

When two Cisco ACI leaf switches (Leaf1 and Leaf2) are configured as vPC peers, and a server (S1) is connected to Leaf1 via a port channel, S1 is learned in the endpoint table of Leaf2 as an "on-peer endpoint."

The on-peer endpoint is a variant of the remote endpoint. These endpoints are remote endpoints that point to a port that is not part of a virtual Port Channel (vPC), also called an orphan port, on a vPC peer leaf. They are special endpoints because they are remote, but they are learned through vPC synchronization on the control plane instead of through data-plane learning from the actual traffic. As a result of vPC synchronization, on-peer endpoints have MAC address, IP address, and EPG information, unlike other remote endpoints, which have either bridge domain (MAC address) or VRF (IP address) information.