Which messaging protocol is used by the vPC peers to communicate with each other?

Question

Options

• ALLDP
• BCFS
• CZMQ
• DVPCT

• B
  3% (1)
• C
  3% (1)
• D
  95% (38)

Explanation

Note: This question appears to contain an error in the answer key. Based on Cisco NX-OS documentation, the correct answer should be B (CFS), not D.

Why B (CFS) is actually correct: vPC (Virtual Port Channel) peers on Cisco Nexus switches use Cisco Fabric Services (CFS) over the peer-link to synchronize state, MAC tables, ARP entries, and configuration between the two peers. This is well-documented in Cisco's official NX-OS vPC guides.

Why the other options are wrong:

• A (LLDP) - Link Layer Discovery Protocol is a neighbor-discovery/advertisement protocol, not used for vPC peer synchronization.
• C (ZMQ) - ZeroMQ is a general-purpose messaging library unrelated to vPC or Cisco NX-OS.
• D (VPCT) - Not a recognized standard protocol in Cisco vPC documentation; likely a distractor.

Memory tip: Think "vPC peers Communicate via Fabric Services" - the C in CFS stands for Cisco, and CFS is the fabric-level glue that keeps both Nexus peers in sync.

If this question came from a third-party exam prep source, treat it with caution. For authoritative material, refer to Cisco's official NX-OS vPC Configuration Guide, which consistently identifies CFS as the vPC peer communication protocol.

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