Subject: [Lime] What is LIME really working on?

From: "Adrian Farrel" <[email-masked]>
Date: Fri, 18 Sep 2015 16:49:12 +0100

Hello LIME WG,

You may be aware that L3SM is building a service model for L3VPN users. That
model can be *mapped* to the models used to operate the network. But the L3SM
model is not intended to provide a base model for L3VPN operation. And it is not
supposed to provide something that is extensible to the protocol models. Later
work will check that the L3SM model can be mapped to the protocol models and
that the protocol models have all the necessary objects for this to work.

But "mapping" is simply taking the description of the service and using the data
to work out what to ask the network to do. It's an orchestration thing and the
model may describe some things that a particular network can't offer. That's OK
and it's what orchestrators do for a living.

Now, a while back when I was looking at the early LIME work I *thought* LIME was
a similar play. That is, I thought its job was to produce a generic model for
requesting OAM services. The model may describe services that can or can't be
provided in a network, or can or can't be provided by a set of specific network
nodes (such as those along a path). A user uses the LIME model to request
services, and an "OAM manager" (or "OAM orchestrator"?) maps to the OAM control
for the network nodes.

It may be that in both cases (L3SM and LIME) the mapping can be made simple if
the base model is extensible to the protocol configuration model, but that is
not a requirement.

IMHO, L3SM makes this clear in the charter, and I *thought* that the LIME
charter was clear on this.

But a lot of the recent LIME discussion seems to focus on:

- can all the function in the base model be provided by the network?
   (for example, things must be left out of the base model because
    ping in an IP network can't support it)

- the base model must only contain things that are needed for
   extending the model to specific protocol models
 
Now, what have I missed? Where did what I thought was the case change to what
people are talking about? 

If I'm crazy-wrong, please tell me.

Thanks,
Adrian