In a VSX environment with multiple VRFs, if you cannot find the IP address of a client device with a known MAC address on the primary switch, which command should you run to locate the IP address across VRFs?

In a VSX environment with multiple VRFs, if you cannot find the IP address of a client device with a known MAC address on the primary switch, which command should you run to locate the IP address across VRFs?

• A. Run on the CX 6100 switch: show mac-address-table
• B. Run on the VSX primary switch: show arp all-vrfs
• C. Run on the VSX primary switch: show mac-address-table
• D. Run on the CX 6100 switch: show arp all-vrfs

Answer: (B)

In a VSX environment with multiple VRFs, finding the IP associated with a known MAC hinges on ARP, not just MAC learning. ARP entries map IP addresses to MAC addresses, and to locate the IP across all VRFs you need visibility across every VRF. Running the ARP lookup on the VSX primary switch with the all-vrfs option pulls ARP entries from every VRF, so you can see which IP corresponds to that MAC anywhere in the VSX domain. This cross-VRF ARP view is what lets you identify the IP even if the device resides in a different VRF than the one you’re initially checking. The MAC table shows where a MAC was learned, not the IP, and doing ARP queries on the other switch types wouldn’t give you the consolidated, cross-VRF view needed here.

In a VSX environment with multiple VRFs, finding the IP associated with a known MAC hinges on ARP, not just MAC learning. ARP entries map IP addresses to MAC addresses, and to locate the IP across all VRFs you need visibility across every VRF. Running the ARP lookup on the VSX primary switch with the all-vrfs option pulls ARP entries from every VRF, so you can see which IP corresponds to that MAC anywhere in the VSX domain. This cross-VRF ARP view is what lets you identify the IP even if the device resides in a different VRF than the one you’re initially checking. The MAC table shows where a MAC was learned, not the IP, and doing ARP queries on the other switch types wouldn’t give you the consolidated, cross-VRF view needed here.