These are some comments on behalf of Jian Lu from the University of Virginia (he had issues registering)

My comments to the spec:
1. Security is vaguely mentioned and given some guidelines to implement it in the last chapter. But not too much details
 are mentioned there.
2, The entire model is an one-to-one model and each data transfer between a sink and a source requires creation of an 
individual DTI. Although I am not sure whether it is reasonable to consider the following scenarios: a single sink with 
multiple different sources or a single source with multiple sinks,  I kinda of feel that dealing with those scenarios 
with multiple independent data transfer instances (the current model) is not optimal because there is certain degree of 
common information can be shared between those instances. And coordination between multiple transfers sharing the same 
sink or source is also more complicated with multiple standalone and independent DTIs.
3. For Chris's comment, I guess the status at the time when the system is undoing a job should be "Failed". I agree that
 it might be better to have another "Undoing" state.

-Jian