Patent ID: 7444428

Claim:
An apparatus comprising: a processor to execute instructions that implement: a proximity estimation unit to send a first number of probe messages to a client agent without waiting to receive a reply message, the proximity estimation unit to receive a first set of reply messages including a largest expired time to live (TTL) value of the first set, and to determine a proximity estimate from the largest expired TTL value of the first set; and a proximity verification unit coupled with the proximity estimation unit, to use the proximity estimate to set a TTL value in each of a second number of probe messages, to send the second number of probe messages including the largest expired TTL value of the first set, to the client agent, to receive a second set of reply messages including a largest expired TTL value of the second set, and to verify that the largest expired TTL value of the first set equals the largest expired TTL value of the second set, wherein the second number is smaller than the first number, so that the proximity estimate can be verified by sending a smaller number of probe messages than the number of probe messages that was sent to determine the proximity estimate.