[Nsi-wg] Message Delivery Layer

[Jeroen van der Ham]

Hi,

On 7 Dec 2012, at 13:41, Jeroen van der Ham <vdham at uva.nl> wrote:
> On 6 Dec 2012, at 16:26, Inder Monga <imonga at es.net> wrote:
>> The MDL layer essentially handles the case when MTL fails to deliver a
>> message. The scenario being, whichever reliable message transport layer or
>> multiple of them below, tries to deliver the message end to end. In case
>> the message does not reach after multiple retries, the error is handed to
>> MDL layer (and yes it is logical). The MDL layer can have a different
>> timeout, choose to deliver the message again or try a differnet mechanism.
>> That is upto the implementor. This prevents the NSI state machine having to
>> deal with message timeouts and retries at the application layer. It
>> simplifies the state machine .
>> 
>> If there is more confusion lets have a skype call.


I want to follow up on this further. You state that if the MTL layer fails to deliver a message somehow. We have stated that the MTL should be a reliable transport mechanism, so a delivery failure means something more complicated is going on.
You're stating that you want to leave it to the implementor to figure out how to deal with this.

That's all fine with me, but why do we have to call this another layer, instead of just stating the above?

Jeroen.