Re: [Anima] Some comments for draft-carpenter-anima-gdn-protocol

[Brian E Carpenter <[e-mail]>]

Hi John and everybody,

Replying to some comments received privately, on the list with permission:
On 09/03/2015 22:55, Sheng Jiang wrote:
> Hi, authors of draft-carpenter-anima-gdn-protocol
> 
> The below are some comments from my colleague, Dr. John Strassner. Although I personally think your protocol designs have the ability to meet his requirements for knowledge exchanging among autonomic nodes, it is better you could discuss directly and maybe include some modification/clarification in the future version. I also encourage you to discuss this in ANIMA mail list openly.
> 
> Best regards,
> 
> Sheng
> 
>> -----Original Message-----
>> From: John Strassner
>> Sent: Friday, March 06, 2015 6:43 AM
>> To: Sheng Jiang; John Strassner
>>
>> Dear Sheng,
>>
>> I read the charter and am starting on the drafts.
>>
>>>> autonomics require the ability to share and
>>>> exchange knowledge in an interoperable fashion. I fail to see how this is
>>>> even discussed in ANIMA.
>>>
>>> BTW, the ability to share and exchange knowledge in an interoperable fashion
>>> looks like GNDP (Generic Discovery and Negotiation Protocol) in ANIMA. This
>>> protocol is designed to support information discovery and bi-direction
>>> negotiation.
>>
>> It appears that GDNP covers some, but not all, of what I am talking about.

Indeed, it isn't claiming to cover everything. The idea is that
draft-behringer-anima-reference-model will evolve to show how things
fit together, which will help us to identify holes.

>> However, the following statement from the GDNP draft is misleading, if not
>> just plain wrong:
>>
>> "In order to fulfil autonomy, devices that embody autonomic service
>> agents need to be able to discover each other, to synchronize state
>> with each other, and to negotiate parameters and resources directly
>> with each other."
>>
>> First, autonomic networks are not necessarily autonomous. Autonomy, in its
>> most generic form, is the ability to have the power for an entity to govern
>> itself. If every network element governs itself without regard to other, higher
>> level principles, you don't even have a network. :-)

Sure. That is the role for what we call "intent" which is defined
in draft-irtf-nmrg-autonomic-network-definitions but is not yet
in Anima scope.

>> Second, the three concepts mentioned in the above excerpt (discoverability,
>> synchronization of state, and parameter negotiation) are necessary but
>> clearly not sufficient to have autonomic operation. I was talking about the
>> ability to exchange knowledge (e.g., all or part of an information model)
>> between entities. It doesn't appear that this is covered in ANIMA yet, though I
>> haven't read all of the materials.

My personal view is that this is going to be resolved topic by topic.
In GDNP-speak that means that it will be resolved by individual Objective
definitions, and GDNP will just act as a neutral carrier. (You can quite
fairly argue that this means we are ducking the problem for now.)
Another way to say this is that each type of autonomous service agent will
solve this problem for its own target parameters.

Now, again IMHO, this is why we state in GDNP that the format of the
value of an objective "...might be inherited from an
existing management or configuration protocol, the objective option
acting as a carrier for that format.  The data structure might be
defined in a formal language, but that is a matter for the
specifications of individual objectives.  There are many candidates,
according to the context, such as ABNF, RBNF, XML Schema, possibly
YANG, etc.  The GDNP protocol itself is agnostic on these questions."

My expectation is that some objectives will need a formal information
model and that others won't, and that there's no reason we couldn't
inherit existing IMs when they are relevant. But that whole question
is also out of charter scope for now. As you know better than most
people, John, defining an IM can become a very laborious business and
for now we want to get started on simple cases that don't need it.

>> If you cannot exchange knowledge, you will
>> never be autonomic in the computer science sense. 

You will find very similar words in draft-irtf-nmrg-an-gap-analysis.

<snip>

Regards
    Brian

>> regards,
>> John
>>
>> Dr. John Strassner, Ph.D.
>> CTO, Software Laboratory, CRD
>>
>>
>> Futurewei Technologies
>> US R&D Center
>> 2330 Central Expressway
>> Building A, office A2-2143
>> Santa Clara, California   95050
>>  Office:  +1.408.330.4923
>>  Email:   [e-mail]
>>
>>
>> Best regards,
>>
>> Sheng