Beacon Probing is used in vSphere networking to:

Beacon Probing is used in vSphere networking to:

A.
discover which uplink has the shortest route

B.
identify when an upstream link failure has occurred

C.
discover alternate default gateway addresses

D.
identify which uplink has the longest reported uptime

Explanation:
VMware Knowledgebase KB 1005577
What is beacon probing? When is it recommended to be used? Beacon Probing is a network failover detection mechanism that sends out and listens for beacon probes on all NICs in the team and uses this information, in addition to link status, to determine link failure.