I have reviewed this document as part of the Ops area directorate's ongoing effort to review all IETF documents being processed by the IESG.  These comments were written primarily for the benefit of the Ops area directors.
Document editors and WG chairs should treat these comments just like any other last-call comments.

Summary: This document suggests some simple techniques for a source to identify its probes. 

This is my second time reviewing the draft. (last review was the -05 version). Thanks for the authors replies, which helps me understand the draft much better. However, there are still unsolved issues:
- Is the "Probe" another ICMP message?  Does the "probe" have an ICMP Header? or just simple "Echo" request? 
- Should a new ICMP code be specified so that target nodes can decode the content carried by the ICMP message? 

Thank you, 
Linda