I think this progress.
I would be more than happy to go over the requirements listed there
and whatever more for an "stretch" analysis needed for both protocol
and model. In other words, some process. A joint draft perhaps.

cheers,
jamal




On Sat, Apr 19, 2014 at 3:16 PM, Andy Bierman <[email protected]> wrote:
> Hi,
>
>
> On Sat, Apr 19, 2014 at 12:08 PM, Joel M. Halpern <[email protected]>
> wrote:
>>
>> I actually expect that YANG can be extended to do what is needed.  I also
>> expect that ForCES protocol can be extended to do what is needed on the
>> protocol side.
>>
>> But that is not the same as saying that either item "as is" meets the
>> needs as stated.
>>
>> It would seem appropriate to at least describe what extensions will be
>> needed to YANG before we decide to say "yes, we will use YANG and we will
>> extend it to address the needs."
>>
>
> I did that already.  See the I2RS slides from IETF #89.
>
>
>> On the ForCES side, I believe Jamal did include that information in his
>> presentation.  Is there a similar list for YANG that I have misplaced?
>>
>> Yours,
>> Joel
>>
>> On 4/19/14, 3:02 PM, Andy Bierman wrote:
>>>
>>>
>>>
>>>
>>> On Sat, Apr 19, 2014 at 11:35 AM, Joel M. Halpern <[email protected]
>>> <mailto:[email protected]>> wrote:
>>>
>>>     There are a number of modeling and protocol expectations (I think
>>>     they can be reasonable called requirements, and I think they have
>>>     been agreed by the working group) in the architecture draft.  Some
>>>     of them are a stretch for YANG.  Some of them are a stretch for
>>> ForCES.
>>>
>>>
>>> I assume you mean sec. 6.4.5?
>>> I did not find anything in there that YANG does not already support or
>>> could not
>>> support with a YANG extension statement.  Since I2RS can define its own
>>> YANG extensions, YANG is ready today to meet all the requirements.
>>> Can you be more specific about the stretch items?
>>>
>>>
>>>
>>>     Yours,
>>>     Joel
>>>
>>>
>>> Andy
>>>
>>>     On 4/19/14, 1:46 PM, Andy Bierman wrote:
>>>
>>>         Hi,
>>>
>>>
>>>         On Sat, Apr 19, 2014 at 8:22 AM, Russ White <[email protected]
>>>         <mailto:[email protected]>
>>>         <mailto:[email protected] <mailto:[email protected]>>> wrote:
>>>
>>>
>>>               > And the basic premise of I2RS is that there are
>>>         requirements for
>>>              the work
>>>               > that were not addressed properly by the existing
>>>         configuration
>>>              protocols.
>>>               > Otherwise the WG would not even need to discuss protocol
>>>              modifications.
>>>               > So the fact that NetConf / YANG works for device
>>>         configuration
>>>              does not
>>>               > seem to be evidence that it works for what I2RS wants to
>>> do.
>>>
>>>              Precisely. Otherwise, we could have just looked at the
>>>         problem, and
>>>              said,
>>>              "let's use YANG." But I think we're starting to confuse the
>>>         problem set
>>>              because we started by trying to boil the ocean. Once you
>>>         actually get to
>>>              town, it's hard to keep in focus that you're just there for
>>>         a new
>>>              pitchfork
>>>              handle -- that game of checkers over there on the porch of
>>>         the hotel
>>>              looks
>>>              so interesting, and the hardware store has so much other
>>>         stuff than just
>>>              pitchfork handles, after all.
>>>
>>>              So, given we are _supposed_ to be focused on the RIB
>>>         interface, and not
>>>              protocol, configuration, device, etc., etc., what specific
>>>         points
>>>              have the
>>>              use cases brought out that either NETCONF/YANG or FORCES not
>>>              fulfill? One of
>>>              the primary points was timing -- are these other systems
>>>         fast enough?
>>>
>>>               >From my perspective, these two systems don't fulfill the
>>> I2RS
>>>              mandate on the
>>>              RIB side for various reasons:
>>>
>>>              - I'm not convinced on the speed side. YANG feels a bit
>>>         heavy weigh
>>>              for what
>>>              we want here. The flexibility is there, but so is the cost
>>>         of that
>>>              flexibility.
>>>
>>>
>>>
>>>         Can you explain how an off-line representation of the data model
>>>         can be
>>>         fast or slow?
>>>         You mean the YANG compiler takes too long to process a YANG file?
>>>         You mean the unspecified I2RS protocol will be too slow on the
>>>         wire if
>>>         it uses XML or JSON encoding of YANG data structures?
>>>
>>>
>>>              - I'm not convinced YANG has handled the atomicity issues
>>>         in a way that
>>>              makes sense for the application environment we have in mind.
>>>              RESTCONF seems
>>>              to go that direction, but I'm not certain it's a complete
>>>         solution (?).
>>>
>>>
>>>         YANG is a data modeling language.
>>>         RESTCONF is a protocol.
>>>         Atomicity is a property of the protocol.
>>>         Which YANG statements prevent this from being accomplished in
>>>         the TBD
>>>         I2RS protocol?
>>>
>>>              So, IMHO, I think we need to either consider FORCES, or
>>>         "something
>>>              new." But
>>>              we're going to have a hard time determining if this is true
>>>         if we
>>>              can't make
>>>              a solid requirements list. For me, these are:
>>>
>>>              - Atomic operations at the RIB level
>>>              - Speed that's comparable to a local routing process
>>> installing
>>>              routes in
>>>              the RIB
>>>              - An immediate feedback system within the RESTful mold that
>>>         tells the
>>>              installing process what happened, and why, with the route
>>>         it just
>>>              tried to
>>>              install in the RIB
>>>
>>>              So, it seems to me that we need to return to the use cases
>>>         -- there
>>>              are two
>>>              in the charter. If we want to discuss adding others, that's
>>>         fine, but we
>>>              need to gain some focus, and stop trying to boil the ocean,
>>>         if we
>>>              want to
>>>              make any progress.
>>>
>>>
>>>         It seems to me this WG needs to start asking the right questions
>>>         about the
>>>         data modeling language requirements.  E.g.:
>>>
>>>             - What are the data types needed?  Is this a static set of
>>>         will it
>>>         ever change?
>>>             - What are the high level data modeling constructs needed?
>>>             - Are user defined types needed?
>>>             - Are re-usable data definitions needed?
>>>             - Does the data model need to be modular?  How does it grow
>>>         over time?
>>>             - Can vendors add data definitions that extend the standard
>>>         definitions?
>>>             - How are new definitions added in a way that does not break
>>>         existing
>>>         clients?
>>>             - How is mandatory to implement vs. optional to implement
>>>         functionality handled?
>>>             - How is mandatory to use vs. optional to use functionality
>>>         handled?
>>>
>>>         You are asking about protocol requirements, not data modeling.
>>>         IMO it would be near-sighted and extremely impractical to choose
>>>         a language that only supported description on RIB info.  I fail
>>>         to see what
>>>         is so special about RIB info that would warrant its own DML.
>>>
>>>
>>>              :-)
>>>
>>>              Russ
>>>
>>>
>>>         Andy
>>>
>>>
>
>
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