Cisco NX-OS supports model-driven telemetry, which allows the switch to send real-time operational data in a structured format such as JSON.
- HTTP (Hypertext Transfer Protocol) is commonly used for transmitting telemetry data encoded in JSON.
- NX-OS uses gRPC or RESTCONF over HTTP/HTTPS for telemetry streaming.
- Telemetry data includes network statistics, event logs, and system state information, which can be collected by monitoring platforms.

The command logging logfile Local 4 size 20000 configures the Cisco MDS 9000 Series Switch to store log messages with a severity of "warning" (which corresponds to severity level 4) and above. The size parameter is set to 20000 bytes, which ensures that the log file does not exceed the specified maximum size1.
References:
* For detailed information on configuring system message logging on Cisco MDS 9000 Family switches, you can refer to the Cisco documentation on system message logging1.

A fabric interface that fails in the port channel does not trigger a change to the host interfaces.
Traffic is automatically redistributed across the remaining links in the port channel fabric interface.
If all links in the fabric port channel go down, all host interfaces on the FEX are set to the down state.
Reference:
https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus2000/sw/configuration/guide/b_ Cisco_Nexus_2000_Series_Fabric_Extender_Software_Configuration_Guide_Release_4_2/b_Ci sco_Nexus_2000_Series_Fabric_Extender_Software_Configuration_Guide_Release_4_2_chapt er_011.html