Hi, On 12 Dec 2012, at 12:36, Inder Monga <imonga@es.net> wrote:
Thanks Jeroen. The introduction of the separate layer as a concept is to help formalize the separation of concerns by handling errors at the MTL layer. If you look at NSI v1, the state machine was integrated and would mean that the state machine would change if you changed the requirements for the MTL layer. This is not the case with NSI v2.0. When people are talking about different MTL's, then we need to make sure that a change in MTL will not change the NSI state machine. The MDL makes that possible.
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. Jeroen.