Comments
11/6

-The paper claims that it provides "user-level" path diagnosis, however 
Laymen cannot really use this tool. This is a presentation problem. Can make
the information collected by the tool easy to understand. Possibly launch
it automatically to help ISP diagnose the problem.

-What information do ISPs have. Not much more than end-users. They use 
RouteViews to check BGP advertisements. In many cases they don't even know
that problems exist. 

-Changes in IP & TCP header. Is it really feasible? Maybe not today but 
this are lessons to be learned for future protocol development (maybe not
even TCP/IP)

-The performance of the tool in terms of Forward loss is not very good...

-Such a tool could be very useful if the end user had more than one pipes to
send traffic. In this case, she could dynamically choose which one to use
based on performance measurements.