Re: [Teas] New Version Notification for draft-wd-teas-ietf-network-slice-nbi-yang-03.txt

"Wubo (lana)" <> Mon, 12 July 2021 10:05 UTC

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Thread-Topic: New Version Notification for draft-wd-teas-ietf-network-slice-nbi-yang-03.txt
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Subject: Re: [Teas] New Version Notification for draft-wd-teas-ietf-network-slice-nbi-yang-03.txt
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Hi Med,

Many thanks for your valuable review and comments. It is not the intention to ignore your suggestion. We will address the comments in the next revision.
Please see inline for the detailed answer with [Bo].

Best regards,

发件人: [] 
发送时间: 2021年7月9日 20:06
收件人: Wubo (lana) <>om>;
主题: RE: New Version Notification for draft-wd-teas-ietf-network-slice-nbi-yang-03.txt

Hi Bo, all,

Thank you for sharing this updated version. 

I'm supportive of this work, but I think we have a fundamental point to clarify: the document is currently missing data nodes that makes a slice, a slice! 

If we don't have such data nodes, the current module can be used to provision any form of connectivity. If we omit the "ns-" prefix, the module can be used for provisioning the connectivity of VoIP, multicast, etc. services. That’s actually good (as the applicability scope is wider) but we need also to think about network slice specifics.  

I have touched on some of these points in a review I shared with you back in 02/21, but unless I'm mistaken I don't think it was addressed: 

Below an extract of my main comments: 

(1) A proposal to rationalize the discussion and ease progressing the spec is to clearly call that a network slice can be defined as a collection of at least three components: (1) connectivity component, (2) storage component, and (3) compute component. Having a provision for this since early stages of the model will ease grafting other components of an IETF slice easily, but also allows to avoid having a linear model.
[Bo]: I think this comment relates with the thread discussion of SFC and slicing. If my understanding is correct, we will add this when WG decides the SF aware network slice is within the scope of draft-ietf-teas-ietf-network-slices. But based on the discussion, I am afraid that someone would suggest a separate YANG model for this.

(2) For the connectivity part, the following items are important to cover as well:
* Traffic steering and advanced services: a slice may require the invocation of service functions (firewall, for example) in a given order. These policies have to be captured in the slice request. This is also useful when the customer request that its slice should not cross some networks or not span some regions. 
[Bo] Thanks. If I understand correctly, we will add SLE(Service Level Expectation)-specific steering policies applied per slice or per slice connection. Are there any other modelling suggestion?

* What to do for out of profile traffic: See the traffic conformance discussion in RFC7297. 
[Bo] I'm not sure I understand this. Do you mean that MTU attributes should be included?

* Activation means: may need to be included in a slice definition. Think about a slice that can be implemented as a VPN service. Such service may require the activation of a given routing protocol between a CE and a PE, otherwise the service won’t be offered. 
[Bo] I do agree. Current YANG model has a container of "ep-protocol" under "ns-endpoint", and also previous revision of the model had nodes of "BGP" and "static routing". But there is some arguments that some scenarios, for example, optical networks don't need these nodes. 

* Invocation means: Think about a multicast service that requires IGMP/MLD and so on.
[Bo] Is this similar with the previous one that you suggest to add IGMP/MLD nodes under "ns-endpoint"?

* Notification means: these are important for service assurance and fulfillment purposes.
[Bo] Yes. The current model includes network slice, endpoint, and connection status. Do you think there are other nodes that are necessary?

(3) The model seems to be inspired from the opsawg vpn I-Ds (network-access structure, for example). That's great and appreciated, but I would formalize that by using I-D.ietf-opsawg-vpn-common for data nodes such as connectivity-type, endpoint-role, status-params, etc. 
Bo: Yes. VPN is one of important technologies of realizing network slice. But there are some discussions that VPN is not mandatory to realize network slice, e.g. optical mechanism could be used.
Therefore we don't reuse the YANG nodes defined in I-D.ietf-opsawg-vpn-common.

(4) One last comment, I still don't get what is an "underlay IETF network".
Bo: Thanks for pointing this out. Will remove 'underlay'.
Thank you. 


> -----Message d'origine-----
> De : Teas [] De la part de Wubo (lana) 
> Envoyé : vendredi 9 juillet 2021 12:18 À : Cc : 
> Objet : Re: [Teas] New Version Notification for 
> draft-wd-teas-ietf- network-slice-nbi-yang-03.txt
> Dear WG and chairs,
> The draft has been aligned with changes in the IETF Network Slice 
> framework WG I-D.
> The Authors believe that it has been maturing with the inputs from the 
> WG, and can be evaluated as a candidate for WG adoption.
> Diff:
> slice-nbi-yang-03
> Best regards,
> Bo (on behalf of the co-authors)
> -----邮件原件-----
> 发件人: []
> 发送时间: 2021年7月9日 17:32
> 收件人: Wubo (lana) <>om>; Dhruv Dhody 
> <>om>; Liuyan Han <>om>; Reza 
> Rokui <>om>; Tarek Saad <>
> 主题: New Version Notification for draft-wd-teas-ietf-network-slice- 
> nbi-yang-03.txt
> A new version of I-D, draft-wd-teas-ietf-network-slice-nbi-yang-
> 03.txt
> has been successfully submitted by Bo Wu and posted to the IETF 
> repository.
> Name:		draft-wd-teas-ietf-network-slice-nbi-yang
> Revision:	03
> Title:		A Yang Data Model for IETF Network Slice NBI
> Document date:	2021-07-09
> Group:		Individual Submission
> Pages:		45
> URL:  
> network-slice-nbi-yang-03.txt
> Status:
> network-slice-nbi-yang/
> Htmlized:
> ietf-network-slice-nbi-yang
> Diff: 
> ietf-network-slice-nbi-yang-03
> Abstract:
>    This document provides a YANG data model for the IETF Network Slice
>    Controller (NSC) Northbound Interface (NBI).  The model can be used
>    by a IETF Network Slice customer to request configuration, and
>    management IETF Network Slice services from the IETF NSC.
> The IETF Secretariat
> _______________________________________________
> Teas mailing list


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