SAM is useful for low-rate control plane traffic (BGP/OSPF hellos, ARP, DHCP) or micro-burst debugging on quiet ports. Not suitable for data plane troubleshooting at scale.
Before you capture a packet, you must ask:
monitor session 1 type local source interface ethernet 1/1-4 both destination interface ethernet 1/48 no shut
: Replicates traffic from a source interface (physical or VLAN) to a local "monitor interface" where a laptop or server is connected.
To capture traffic being forwarded between data ports in hardware, you must replicate it to a monitoring station.
A simpler ACI capture method involves using the traceroute command to generate packets. By specifying a source interface, you can verify if a policy (Contract) is allowing traffic without needing a full capture.
This is the bread and butter of Nexus 9k packet capture.
Models: N9K-C93xx, N95xx, N96xx running ACI Mode.