Just an added note on this. On Wed, 12 Dec 2012, Jeroen van der Ham wrote:
From your messages, I believe you agree this functionality is needed in NSA. What you are disagreeing is the formalization of that functionality into a layer. Maybe the NSI group can comment on that as well or you can make a formal proposal to the group to change it?
Exactly. Having thought about this, what I do not like about the layering model of the MDL and MTL is the fact that NSI is drawing them into the whole architecture and representing them as part of NSI. In my mind they are requirements to an outside protocol/transportation mechanism that is already there and should not be represented as part of NSI-CS.
In Oxford the aggregator state machine was getting somewhat messy, as it essentially had to keep track of all children, and possibly retries as well. The MDL was suggestion as an abstraction to encapsulate the sending and receiving of these message into a single succeed/fail mechanism. It is also the task the MDL to try and undo any succesfull changes in case one or more sub-connections failed. Sorry, if something like this has already been mentioned. Best regards, Henrik Henrik Thostrup Jensen <htj at nordu.net> Software Developer, NORDUnet