On Thu, Jun 04, 2015 at 03:52:15PM -0400, Susan Hares wrote:
> Juergen: 
> 
> I understand your technical point on being concerned about 
> 
> "solutions that require (i) separate data models for ephemeral state and
> (ii) data model specific merge logic. While this may work for I2RS, this
> approach does not scale or has a very high cost of scaling to other
> ephemeral state editing needs."
> 
> If you have full overlay model proposal, we would be glad to receive it.
> However, no one else has proposed a full overlay model.

Frankly, there is no full alternate proposal either. The overlay model
has been discussed at quite some detail at a NETMOD interim. I am
happy to point at the meeting minutes. The question perhaps really is
whether (a) I2RS has requirements to be addresses and NETMOD/NETCONF
looks at solutions or whether (b) I2RS casts a solution into stone to
be run through the NETCONF working group or whether (c) creates a
solution on its own independently of any other NETMOD/NETCONF
requirements.

> Other answers are below.
> 
> Sue 
> 
> -----Original Message-----
> From: Juergen Schoenwaelder [mailto:[email protected]] 
> Sent: Thursday, June 04, 2015 2:24 AM
> To: Susan Hares
> Cc: [email protected]; [email protected]; 'Joel M. Halpern'; [email protected];
> 'Alia Atlas'
> Subject: Re: [i2rs] I2RS minutes for the I2RS Interim (5/27/2015)
> 
> On Wed, Jun 03, 2015 at 08:49:41PM -0400, Susan Hares wrote:
> > The minutes for the I2RS meeting are at: 
> > 
> >  
> > 
> > www.ietf.org/proceedings/interim/2015/05/27/i2rs/minutes/minutes-inter
> > im-201
> > 5-i2rs-8
> > 
> >  
> > 
> > These minute provide a lengthy of issues in the requirements.  From 
> > these minutes, there are the following 6 conclusions on the protocol 
> > requirements that Jeff stated:
> > 
> >  
> > 
> > 1)      There will be no consideration of an overlay model unless a fully
> > formed proposal is presented. 
> > 
> > Jeff and I appreciate Ken Watsen's comments on the list, but we have 
> > had lots of suggestions regarding an overlay proposal - but no full 
> > proposal.  At this time, the WG will only consider full proposals and 
> > not suggestions toward a proposal.
> 
> For the record: I am highly concerned about solutions that require (i)
> separate data models for ephemeral state and (ii) data model specific merge
> logic. While this may work for I2RS, this approach does not scale or has a
> very high cost of scaling to other ephemeral state editing needs.
>  
> > 2)      Jeff's document provides details on ephemeral state requirements
> > that have not changed.  These requirements include:
> > 
> > a.       Highly reliable notifications (but not perfectly reliable
> > notifications)
> > 
> > b.      High bandwidth, asynchronous interface, with real-time guarantees
> on
> > getting data,
> > 
> > c.       Node identification of clients that write by client identity,
> > secondary identity, and priority.  Data models will determine what is 
> > the "node" unit.  For example, the I2RS RIB node unit is the route.
> 
> I am concerned about adding protocol mechanisms that are specific to a
> certain data model. It is unclear what a "node" unit it, terms like 'highly
> reliable notifications' and 'high bandwidth, asynchronous interface, with
> real-time guarantees' are somewhat unclear - how do we determine we have met
> any of these requirements?

Apparently no answer here...

> > d.      There is one priority per client. 
> > 
> > e.      Priority is kept in the NACM at the client level [rather than path
> > level (5/27 meeting) or group level (list discussion).  
> 
> Why does this mapping of username to priority have to be maintained in NACM?

Apparently no answer here...

> > 3)      Joel suggests that large data write may be best done in netconf
> with
> > guarantees
> > 
> > a.       I2RS will be focused on highly asynchronous interfaces with less
> > than full routing tables. 
> > 
> > b.      A client whose large data is interrupted by a notification has a
> > difficult time determine when the notification happened in the stream 
> > - so the I2RS client must ask the agent again.
> > 
> > c.       Logging for traceability is different than event notification. 
> 
> Except c), I do not understand this. What are these 'guarantees' 3) is
> about?
> 
> [Sue]: The large database pulls of a I2RS RIB (1 million routes) may receive
> a change notification for one of the routes while the rest of the stream is
> in progress. If the change notification does not include the data, the  I2RS
> client must poll the I2RS agent to determine if the route change
> notification occurred before or after that route's data was sent. 
> Change notifications are reliable, but not perfectly reliable.  Logging is
> different than change notifications as logging for tracing includes all
> change data reliably.

I am still confused what the requirement here is.

> > 5)      Secondary identity data is read-only meta-data that is stored in
> the
> > agent associated with a data model node that is being created or 
> > updated  (write-access) in the data store.  
> 
> Ehem, what is read-only data that is created or written? Did you want to say
> that the identity meta-data is immutable once a data node has been created?
> And if so, has priority the same property: Is priority of a data node is
> determined at creation time and then immutable?
> 
> [sue]: Secondary identity data is read-only meta-data that is only changed
> when created or written. It is immutable unless the whole node is changed.
> Priority is linked to I2RS client.  Priority remains unchanged with the
> identity of the client.

You can't ever change the priority of a client? I doubt this is
practical.

> Priority of an entry (route1 from client-1, priority2) remains
> immutable with the writing of this entry from this client.  If a new
> client (route-1 from client-2, pririty3), then the node and the
> meta-data changes.

So I understand the priority is determined at write time but then
sticking until the next write. Or in other words, to change the
priority I have to write the data again using a client with a
different priority (or using the same client in case priority of a
client turns out to be configurable).

> > 6)      I2RS Client and Agent Identities are mutually authenticated by
> > Authentication server (AAA),
> > 
> > The values of identities are originally set by operators.   
> >
> I am not sure how agent identity authentication via AAA works. Can someone
> point me to the right direction if I assume a secure transport such as SSH
> or TLS?
> 
> The identities used in SSH are passed via AAA (diameter or radius).  The
> identities are not standardized but sent in AAA (diameter or radius)
> messages based on operator assignment.

I know how I can pass the client identity via AAA using SSH, I like to
see an explanation how that is supposed to work for server identities
(and which operational problem that solves).

/js

-- 
Juergen Schoenwaelder           Jacobs University Bremen gGmbH
Phone: +49 421 200 3587         Campus Ring 1 | 28759 Bremen | Germany
Fax:   +49 421 200 3103         <http://www.jacobs-university.de/>

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