Council of Orchestration Protocol

Council of Orchestration Protocol in Cisco ACI is a protocol used for the exchange of endpoint information between leaf and spine switches in the ACI fabric. It is part of the control plane and plays a critical role in ensuring efficient communication and forwarding of traffic within the fabric.

Fig 1:Council of Orchestration Protocol

Here’s a detailed explanation of COOP in ACI:

1. Purpose of COOP in ACI

In Cisco ACI, the leaf switches maintain endpoint information for devices connected to them. This includes IP addresses, MAC addresses, and VLAN or EPG information. COOP ensures that this endpoint information is consistently distributed to all spine switches, which act as the central repository for endpoint data.

2. Role of Spine and Leaf Switches

Leaf Switches: Connect directly to endpoints (hosts, servers, or VMs). They detect and register endpoint information and share it with the spines using COOP.
Spine Switches: Act as COOP servers, maintaining a centralized database of endpoint information. They respond to leaf queries for specific endpoint details.

3. How COOP Works

COOP is based on Reliable Transport Protocol (RTP) and operates over TCP. Here's how it works:

Endpoint Discovery:
- A device connects to a leaf switch.
- The leaf switch identifies the endpoint's MAC and IP addresses and its associated EPG or VLAN.
Registration with Spine:
- The leaf switch sends an Endpoint Registration message to a spine switch using COOP.
- This message contains the endpoint information, including MAC address, IP address, and other relevant attributes.
Database Update:
- The spine switch updates its COOP database with the endpoint information.
- This database is replicated across all spine switches for redundancy.
Querying Endpoint Information:
- When a leaf switch needs to forward traffic to an endpoint, it queries the spines using COOP if the information is not locally available.

4. Components of COOP

COOP Protocol: Facilitates communication between leaf and spine switches.
RIB (Routing Information Base): Contains routes to endpoints, updated using COOP.
Policy: Ensures endpoint information distribution complies with ACI policies.

5. Key Features

Reliability: COOP uses TCP, ensuring reliable delivery of messages.
Scalability: The distributed architecture allows the fabric to scale without bottlenecks.
Resiliency: Redundancy in spine switches ensures no single point of failure.
Efficiency: Spine switches store summarized information, avoiding the need for each leaf switch to maintain a full database of all endpoints.

6. COOP Message Types

Hello Messages: For COOP neighbor discovery and keepalive.
Registration Messages: Used by leaf switches to register endpoint information.
Query Messages: Used by leaf switches to query endpoint information from spines.
Update Messages: Sent to update endpoint information as changes occur.

7. Monitoring COOP

Cisco ACI provides tools to monitor COOP behavior:

CLI Commands:
- show coop internal info: Displays internal COOP information.
- show coop endpoints: Lists endpoints registered in the COOP database.
APIC GUI: COOP statistics and logs can be viewed in the fabric's operational dashboard.

8. Benefits of COOP in ACI

Optimized Traffic Forwarding: Ensures fast and accurate endpoint lookup.
Centralized Endpoint Database: Simplifies management and improves control plane efficiency.
Support for Dynamic Environments: Handles endpoint mobility and dynamic changes efficiently.

9. Common Issues and Troubleshooting

Endpoint Registration Failures: Check COOP connectivity between leaf and spine switches.
Incomplete Endpoint Information: Ensure spines have a complete COOP database and troubleshoot any synchronization issues.
High Latency: Monitor COOP traffic for excessive delays or packet loss.

By enabling efficient and scalable endpoint management, COOP ensures Cisco ACI fabrics operate smoothly, even in complex and dynamic network environments.