Re: [Ibnemo] [Supa] 答复: SUPA call: 7:30-8:30am, Monday, July 13, San Francisco time

["Susan Hares" <[e-mail]>]

John and Yinben: 

 

It appear my flight-dazed mind missed a few things.  Like the correct posting name for my overview draft for IB-Nemo. It is the following: 

 

https://datatracker.ietf.org/doc/draft-hares-ibnemo-overview/

 

You can see an updated version at www.nemo-project.net, and I’ve attached a copy to this email. 

 

Sue 

 

From: Supa [mailto:[e-mail]] On Behalf Of Susan Hares
Sent: Friday, July 17, 2015 8:00 PM
To: 'John Strassner'; 'Xiayinben'
Cc: 'Scott O. Bradner'; [e-mail]; [e-mail]; 'Tina TSOU'
Subject: Re: [Supa] 答复: SUPA call: 7:30-8:30am, Monday, July 13, San Francisco time

 

John: 

 

The premise of Nemo is still the 80/20 rule – of trying to provide a simple model for 80% of the application with 20% of the commands.   We posit two points:  

1)       IBNemo’s 15 specific commands for targeted use cases are better than the generic commands.  

2)      IBNemo’s 15 specific commands are better than NETCONF or RESTCONF commands 

 

In order to confirm our assumptions, we have proposed to prove this for specific use cases (see hares-overview.   This work includes checks on the user’s range of inputs, the expected output, and the prototype IBNemo code, and looks at the SUPA intent policy.  The user’s input includes:  use cases and potential intent policy.  

 

What’s the benefit for IB-NEMO for SUPA’s work?   SUPA’s defining generic policy information models for ECA and Intent.  While we have many examples of ECA policy over the last 30 years in IETF, we do not have many examples of Intent policy.   IB-Nemo will benefit from SUPA’s definition and design work.  One thing that would be useful, is to post how SUPA’s model can guide IB-Nemo’s user policy or IB-Nemo’s translation of user policy into network-wide policy in the network management system. 

 

What the benefit for IETF for IB-Nemo’s Work?  IBNemo presents a light weight protocol designed for application to network controller use. The design of a protocol will include feeding into network-wide yang modules.  NETCONF/RESTCONF were designed for device level single node usage.   

·         If IBNemo succeeds in standardizing a new protocol, then two different protocols (NETCONF/RESTCONF/) and IBNemo can feed the network-wide models.  

·         If IBNemo work does not prove to be more efficient (Juergen’s supposition), then RESTCONF will have specific proof that RESTCONF is sufficient design for both device-level and network-wide level.

 

See my comments on the discussion below. 

 

https://datatracker.ietf.org/doc/draft-hares-ibnemo-overview/  - provides some use cases. 

 

Best wishes, 

 

Sue Hares 

 

From: Supa [mailto:[e-mail]] On Behalf Of John Strassner
Sent: Thursday, July 16, 2015 7:47 PM
To: Xiayinben
Cc: [e-mail]; [e-mail]; Susan Hares; Scott O. Bradner; Tina TSOU
Subject: Re: [Supa] 答复: SUPA call: 7:30-8:30am, Monday, July 13, San Francisco time

 

What, exactly, are you not agreeing with in the following sentence:

"NEMO uses a flatter, simpler object model with fewer objects to represent targets of policy. NEMO does not define a policy model, and does not support ECA policies. NEMO uses a condition-action paradigm to execute its policy commands.”

 

Lets take the sentence point by point.

 

#1 FLATTER, SIMPLER OBJECT MODEL

NEMO defines three objects: node, link, and flow. How many managed objects do G.805 or G.809, let alone the average MIB, define? It is irrelevant that you can define subclasses of node - the user has to do all the work, and this guarantees non-interoperable solutions.

 

[Sue]: Rather than consider the possible number of managed objects, you need to look at the ones which are used by the use cases.  An example of this is the control of the routing functions on a devices.  The interface and route changes are most frequently used. 

 

#2 TARGETS OF POLICY.

You just said that you define an object model and an operation model. Both would be policy targets, by any standard CA or ECA definition.

[Sue]:  In the world of policy, both an object model and an operation model can be consider policy targets.   And in the academic sense – both can be consider policy.  However, we are trying to describe the difference between the user’s policy view,  the network-wide policy model, and the device-level policy.

 

#3. NEMO DOES NOT DEFINE A POLICY MODEL

You said: "NEMO doesn’t NEED to define a new policy model, because industry already has well defined policy model(such as RFC 3460). We will not rebuild a wheel." Not only did you agree that you aren't defining a policy model, but you appear to be unaware of why RFC3460 is badly broken. So yes, you do need to rebuild this.

 

[Sue]: See #2.  IB-NEMO is looking at Intent policy at the user-level that results in network-wide policy for the network management system. The network-management system will distribute this to devices.  I agree RFC3460 does not cover all use cases and has some technical difficulties. However, there is wisdom from that generic model guides the IB-NEMO translation of user policy to network policy.  If SUPA provides additional wisdom from ECA or Intent-based policy to guide IB-NEMOs translation of user policy to network policy, it would be good to post that here. 

 

#4. DOES NOT SUPPORT ECA POLICIES. NEMO USES A CONDITION-ACTION PARADIGM TO EXECUTE ITS POLICY COMMANDS.

It is inconceivable to me how you could disagree with this. From draft-xia-sdnrg-nemo-language-02, Section 5.1: "All the policies follow the same pattern "when <condition>, to execute <action>, with <constraint>", and can be applied to any entity." This is NOT an ECA policy; any useful implementation of CA or ECA allows constraints - EXCEPT RFC3460.

 

[John]: This is a good step forward from RFC3460 to agree that any ECA/CA implementation allows constraints.  Can you provide us the SUPA intent generic model with the same type of constraints?  

 

Sue 

 

-----------------

On Wed, Jul 15, 2015 at 6:38 PM, Xiayinben <[e-mail]> wrote:

Hi Tina and all,

 

I do not agree with your word about NEMO/ibnemo in page 8.

 

Your sentence: “NEMO uses a flatter, simpler object model with fewer objects to represent targets of policy. NEMO does not define a policy model, and does not support ECA policies. NEMO uses a condition-action paradigm to execute its policy commands.”

The truth is that NEMO define an object model and an operation model to represent network abstraction for intent NBI, because NEMO’s target is a simplified network interface(Intent NBI) for application even for ender-user.  policy is only a type of operation in Intent NBI. NEMO doesn’t NEED to define a new policy model, because industry already has well defined policy model(such as RFC 3460). We will not rebuild a wheel.

 

Your sentence: “IBNemo – 'intent' means I express a desired topology and its properties.”

The truth  is that Ibnemo –‘Intent’ means user simply and intuitively  express demands of network resource and/or network behavior. Topology and its properties are typical type of network resource, so they are part of network intent, but not all. 

 

Best regards,

Yinben 

发件人: Supa [mailto:[e-mail]] 代表 Tina TSOU
发送时间: 2015年7月15日 15:42
收件人: Scott O. Bradner; Susan Hares
抄送: [e-mail]
主题: Re: [Supa] SUPA call: 7:30-8:30am, Monday, July 13, San Francisco time

 

Dear all,

 

Enclosed pls find the updated slides based on Monday July 13 call discussion, only page 8 added.

  

 

Thank you,

Tina

 

From: Supa [mailto:[e-mail]] On Behalf Of Tina TSOU
Sent: Friday, July 10, 2015 4:31 PM
To: Scott O. Bradner; Susan Hares
Cc: [e-mail]
Subject: Re: [Supa] SUPA call: 7:30-8:30am, Monday, July 13, San Francisco time

 

Dear Scott and Sue,

 

Regarding “2.2. Relationship to other WGs (Scott/Sue et al, 5 minutes)” (Times are the ones in the call next week – not the BOF), attached is a quick update based on Jun’s presentation in last BoF, according to the discussion after Dallas.

 

Feel free to use or update the slides.

  

 

Thank you,

Tina

 

From: Supa [mailto:[e-mail]] On Behalf Of Tina TSOU
Sent: Tuesday, July 07, 2015 7:05 AM
To: [e-mail]
Subject: [Supa] SUPA call: 7:30-8:30am, Monday, July 13, San Francisco time

 

Dear all,
 
Below is the draft agenda and logistics for next call during 7:30-8:30am, Monday, July 13, San Francisco time.
 
Look forward to talking to many of you at the meeting.
 
----------
1. Note Well, logistics, agenda bashing (chairs, 5 min)
 
2. Slides Preparation for the BoF (Times are the ones in the call next week – not the BOF)
 
2.1. Goals, Framework, Examples (Max, Oscar (Luis) et al, 10 minutes)
2.2. Relationship to other WGs (Scott/Sue et al, 5 minutes)
2.3. Information Model Overview (John et al, 5 minutes)
2.4. Data Model Overview (Andy et al, 5 minutes)
2.5. Charter presentation (Dan/Juergen et al, 10 minutes)
2.6. Discussion on whether the progress assessment implies going forward changes to the charter (all, 15 minutes)
2.7. Questions to the audience (chairs, 10 minutes)
 
-----------
 
 
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Thank you,
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-- 

regards,

John