[Nsi-wg] Message Delivery Layer

[Inder Monga]

Thanks Tomohiro and Henrik for the details - I had not mentioned the
aggregation/coordination of the messages for enabling the 'tree'
function of the NSI.


-Inder
(Mistakes attributed to thumb-typing on a mobile device)

On Dec 12, 2012, at 3:44 PM, Tomohiro Kudoh <t.kudoh at aist.go.jp> wrote:

> Hi all,
>
> I think MDL is not an appropriate name, and the name should be changed.
>
> In my idea, (former) MDL should support the following things:
>
> 1. Aggregate/segregate messages. For a request, message should be sent
> to children designated by a path finding. For replies and notifications,
> they should be aggregated appropriately (depending success or fail).
> Those functions have not been well documented yet.
>
> 2. Support uRA initiated message delivery retry. There is a request
> (especially from John) to support retry by uRA, after message delivery
> (by MTL and other) is failed. This is to do retry after service plane
> connection recovery which may occur after a certain period of time
> (minutes?). This is currently supported by the state machine, but I am
> proposing to move this to the (former) MDL.
>
> 3. To signal state machines for transition. For example, Activate state
> machine transition is not well described by the state machines only.
> Such behaviors should be specified as a specification of the (former)
> MDL.
>
> Note that MTL is under the web services layer, and (former) MDL is on
> top of the web services layer.
>
> Tomohiro
>
>
> On Wed, 12 Dec 2012 15:23:48 +0100
> Jeroen van der Ham <vdham at uva.nl> wrote:
>
>> Hi,
>>
>> On 12 Dec 2012, at 12:36, Inder Monga <imonga at 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.
>>
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>