This comment came in after the public comment period was over but it should be addressed for the final version of the 
spec.

4.1.2.1 for referring SRM,
for clarity, it would be good to spell out "Storage Resource Manager (SRM)"
so that people without such background can see what it is. The reference can
be made for OGF GFD-R-P.129  The Storage Resource Manage Interface
Specification Version 2.2 and the web link http://sdm.lbl.gov/srm-wg.
Also, wouldn't that make sense to have one more box in Figure 1 for SRM on
both source and sink?