In ACI, Contracts are the policy objects that define how Endpoint Groups (EPGs) can communicate. Within a Contract, Subjects contain the specific filter rules (like permit/deny) that can be based on Layer 3 (IP) and Layer 4 (TCP/UDP port) information. An EPG defines a collection of endpoints, a Bridge Domain defines a Layer 2 broadcast domain, and a VRF provides Layer 3 routing isolation. The requirement for Layer 4 filtering points directly to the use of filters within a Contract Subject.

When a Nexus switch acts as an FCoE Forwarder (FCF) to connect to traditional FC fabric and also as a Fibre Channel Bridge (FCB) to connect to native FC storage, it requires two specific interface roles. The ‘FCoE NPV’ (N-Port Virtualizer) feature allows it to act as an NPIV-capable switch to the upstream FCF/Fabric. The ‘FC End-Host’ feature allows its interfaces to behave like host bus adapters (HBAs) to connect to the native FC storage targets. ‘FC Target’ is for interfaces acting as storage arrays, and ‘FC Initiator’ is for server-facing interfaces, which are not the correct roles in this bridge scenario.

Idempotency in Ansible for network devices is often managed by the ‘state’ parameter in resource-specific modules (like nxos_vlan, nxos_interface). The ‘merged’ state ensures the playbook adds only missing configuration parts, making subsequent runs cause no change. The ‘replaced’ state can also be idempotent but is more invasive. The ‘backup’ option only creates a backup file and doesn’t affect idempotency. ‘check_mode’ is for testing. The ‘nxos_command’ module is for arbitrary commands and is generally not idempotent by itself, making it less desirable for configuration management.

Cisco MDS SAN Analytics, part of the SAN Insights suite, uses Policies to define threshold-based monitoring for key metrics like latency, IOPS, and throughput. The ‘SAN Insights > Policies’ section is specifically designed for creating, modifying, and managing these custom alert conditions. The Dashboard shows data but not configuration. DCNM SAN is for broader fabric management. Smart Call Home is for event-based notifications, not proactive performance thresholding.

The ‘Adapter Fabric Failover’ policy, when enabled on a vNIC within a UCS service profile, allows the vNIC to fail over to a different physical fabric interconnect port (typically on the other fabric interconnect) if its primary path fails. This provides high availability at the hardware level. ‘Failback’ controls behavior after recovery. A ‘QoS Policy’ manages bandwidth. A ‘Pin Group’ is related to how a vNIC is associated with physical ports but doesn’t by itself enable automatic failover.

To integrate a VMware vSphere cluster using its native Distributed vSwitch (DVS) with Cisco ACI, you must create a VMM (Virtual Machine Manager) Domain with the ‘VMware’ policy type. This mode allows ACI to program the VMware DVS via the vCenter API. ‘AVS’ is the ACI Virtual Switch, an alternative to the standard DVS. Using the fabric as a simple access layer with VLANs does not provide ACI policy integration. A Static EPG binding is for physical servers or non-integrated hypervisors.

The command ‘show forwarding adjacency host ‘ is a powerful troubleshooting tool on Nexus switches in a VXLAN fabric. It shows the exact forwarding path for a given host IP, including the outgoing interface, the next-hop (which is the remote VTEP IP), and the VNI used for encapsulation. This directly tests the data plane resolution. ‘show nve peers’ shows NVE interface peers but not host-specific paths. ‘show bgp l2vpn evpn summary’ shows BGP session status. ‘show ip route’ shows the control plane route but not the specific encapsulation details.

In DCNM, Switch Policies (found under the Policy Manager) are used to define reusable configuration blocks for common services like NTP, DNS, SNMP, SYSLOG, etc. These policies can be assigned to one or multiple switches (or switch profiles) and are pushed as part of the switch discovery or template application process. Fabric Templates define the overall fabric architecture (like underlay). Image Management handles software upgrades. Configuration Archive is for backup/restore.

For an ISL between two core switches (or any two switches forming a fabric), the ports should be configured as E Ports (Expansion Ports). To allow multiple VSANs to traverse this single physical link, trunking must be enabled on the ISL, and the specific VSANs must be allowed on the trunk. TE ports (Trunking E ports) are the standard for this role. F ports are for connecting to N ports (devices). NP ports are for NPV mode. Using the default VSAN 1 only is not a scalable or common practice for a core ISL.

In ACI, Contracts are the policy objects that define how Endpoint Groups (EPGs) can communicate. Within a Contract, Subjects contain the specific filter rules (like permit/deny) that can be based on Layer 3 (IP) and Layer 4 (TCP/UDP port) information. An EPG defines a collection of endpoints, a Bridge Domain defines a Layer 2 broadcast domain, and a VRF provides Layer 3 routing isolation. The requirement for Layer 4 filtering points directly to the use of filters within a Contract Subject.0