Re: [Teas] terminology discussion network slicing

[Igor Bryskin <[e-mail]>]

Hi Cristina,

You said:

[Cr] 

2) Unlike hard isolation technologies (e.g., FlexE), even bound to other TE-tunnel or resource reservation protocols, different VPNs still have the risk of underlying resource competition in extremes.


On this I fully agree with you. Dynamically re-configurable L3/L2 network topologies supported by hard separation transport connectivity (such as OTN or FlexE) have a potential to deliver far better level of separation than legacy L2/K3 VPNs. The work done in TEAS WG can greatly help the IETF network slicing story.

Cheers,
Igor  


-----Original Message-----
From: qiangli (D) 
Sent: Wednesday, May 24, 2017 4:40 AM
To: Daniele Ceccarelli; Igor Bryskin; Leeyoung; [e-mail]
Cc: [e-mail]
Subject: 答复: [Teas] terminology discussion network slicing

Hi Danielle and Igor,

please see my reply inline below, marked as >>[Cr].


Best regards,

Cristina QIANG


-----邮件原件-----
发件人: Netslices [mailto:[e-mail]] 代表 Daniele Ceccarelli
发送时间: 2017年5月24日 5:01
收件人: Igor Bryskin; Leeyoung; [e-mail]
抄送: [e-mail]
主题: Re: [Netslices] [Teas] terminology discussion network slicing

Hi Igor,

let me try to answer in line.

Cheers
Daniele  (with a single L) :) 

-----Original Message-----
From: Netslices [mailto:[e-mail]] On Behalf Of Igor Bryskin
Sent: sabato 20 maggio 2017 00:12
To: Daniele Ceccarelli <[e-mail]>; Leeyoung <[e-mail]>; [e-mail]
Cc: [e-mail]
Subject: Re: [Netslices] [Teas] terminology discussion network slicing

Hi Danielle,

Network slicing may have nothing to do with radio. 5g is just a big reason as to why the interest/focus is back on network slicing, which is a very old concept. I don't think that anyone is arguing with what you wrote.

[>DC] Whether the network slice has to do with radio depends on the definition of network slice. If we focus on the "transport" slice then I agree with you, but the network slice IMO spans multiple domains/segments and radio can be one of them (as well as e.g. the cloud)

 The questions are:
a) how do you manage these "pieces"?
[>DC]  I would say independently in each domain/segment and then at the orchestration level someone will be in charge to put the pieces together.
>>[Cr] This question is related to the architecture of netslice. Daniele's answer is just one possibility (i.e, independently in each domain/segment + a common orchestration platform above). I can see another possibility that is independently each domain/segment + cross-domain/cross-segment negotiation & interoperation. IMO, the latter one may be more practical for netslice, since an end-to-end slice may involves different operators/administrative regions, and there does not exist a common platform.

b) what policy infrastructure should be put in place?
[>DC] good question. This definitely needs to be end to end, since the user is paying for it.

c) how do you ensure their separation or, conversely, the degree of resource sharing?
[>DC] Again per domain/segment. In the cloud you might have different slices sharing the same VNG (e.g. IMS or Packet Core), while in the "transport" you might have different slices sharing a same tunnel or having dedicated one.

d) why exactly legacy VPNs are not good enough?
[>DC] IMO legacy VPNs are good enough as "transport" slice. There are several mechanisms to e.g. extend them from the "transport" domain to the cloud domain or to stitch them to e.g. VXLAN in the DC. They just need to be bound to a TE-tunnel or an ACTN VN if you want to have guaranteed SLA for the service using such VPN
>>[Cr] I will not deny that VPN could be one of the solutions for network slicing. However, it still has some deficiencies: 
1) as a overlay technology, it has little control of network resources 
2) Unlike hard isolation technologies (e.g., FlexE), even bound to other TE-tunnel or resource reservation protocols, different VPNs still have the risk of underlying resource competition in extremes.
   

Cheers,
Igor


  

-----Original Message-----
From: Teas [mailto:[e-mail]] On Behalf Of Daniele Ceccarelli
Sent: Friday, May 19, 2017 4:19 PM
To: Leeyoung; [e-mail]
Cc: [e-mail]
Subject: Re: [Teas] terminology discussion network slicing

Hi Young, all,

i agree with your conclusion but would like to clarify one thing that IMO got lost in the discussion since its beginning.

The 3GPP definition says: 
"A set of network functions and the resources for these network functions which are arranged and configured, forming a complete logical network to meet certain network characteristics."

This means that a network slice IS NOT a VPN or a TE Tunnel.
A network slice is "something" (netslices and 3GPP will define what this something is) that is composed by a "piece" in the RADIO domain, a "piece" in the CLOUD domain, a "piece" in the TRANSPORT domain, plus possible other pieces in possible other domains.

The word "transport" can be misleading here since one could think of transport technologies (e.g. WDM, OTN), but what I'm referring to as TRANSPORT DOMAIN is that part of the network that is used to carry a packet between two other domains. 
In order to have a slice, that portion of the transport domain needs to be engineered, hence it is all about building a TE entity and stitching services to such entity. This is what is in the ACTN scope.

My very personal opinion is that whatever belongs to the transport domain belongs to IETF (and is already being addressed), while the rest is a dangerous duplication of concepts standardized is other SDOs...but this is another discussion that doesn't fit here.

BR
Daniele  


-----Original Message-----
From: Teas [mailto:[e-mail]] On Behalf Of Leeyoung
Sent: venerdì 19 maggio 2017 15:15
To: [e-mail]
Cc: [e-mail]
Subject: Re: [Teas] terminology discussion network slicing

Hi,

Lou is right. There is a dedicated email list for the discussion of "network slicing (cc'ed)" and the discussion about what that term means should be held on that list. 

We have used similar language in draft-ietf-teas-actn-framework right from the
00 version. Recent changes have been an attempt to clarify what the terminology means in the context of ACTN. We are not trying to define or redefine "network slicing" in the ACTN document, but are trying to make it clear how ACTN works.

Therefore I propose the following resolution:

1. All discussion of the general applicability and definition of "network slicing" is held on the netslices mailing list.

2. We adopt Adrian's suggestion to explain that the scope of the definition of the terms used in the ACTN framework is limited to ACTN. That means effectively that if there are components of a wider definition of network slicing that are not supported by ACTN, that will be OK. 

I propose to post an updated version in the next few days and I believe that will allow this draft to move ahead without being blocked by the discussion in netslices. Once the IETF has a stable definition of network slicing we can return and see how ACTN is applicable to that definition an whether more wok is need (in a separate draft).

Thanks,
Young

-----Original Message-----
From: Lou Berger [mailto:[e-mail]]
Sent: Tuesday, May 16, 2017 8:35 AM
To: Igor Bryskin <[e-mail]>; Belotti, Sergio (Nokia - IT/Vimercate) <[e-mail]>; Gert Grammel <[e-mail]>; Leeyoung <[e-mail]>; [e-mail]; [e-mail]
Subject: Re: [Teas] terminology discussion network slicing

Perhaps it's time to bring the discussion to the slicing list and report back their reaponse....

Lou


On May 16, 2017 8:31:19 AM Igor Bryskin <[e-mail]> wrote:

> Hi Sergio,
>
> I would also like to hear more from network slicing experts.
>
> My understanding is that the difference in the separation (in terms of 
> control and data planes, security, etc.). For example, traditional BGP 
> based L3 VPNs (that use provider's common control plane for their 
> management and IP/MPLS TE tunnels to inter-connect their PEs) will 
> probably not be able guarantee for the clients msec range connectivity 
> setup times required by 5g, while provided by the same provider fully 
> separated/genuinely private IP/MPLS networks (that do not share 
> IP/MPLS control plane and infrastructure, whose network topology is 
> supported by separate L0/L1 connections) hopefully will be able to 
> provide such guarantees. Therefore, I define layer network slices as 
> dynamically managed fully isolated in control and data planes private 
> TE layer networks, which may share one or more underlying server layer networks.
>
>
> Cheers,
> Igor
>
>
>
>
> -----Original Message-----
> From: Teas [mailto:[e-mail]] On Behalf Of Belotti, Sergio 
> (Nokia - IT/Vimercate)
> Sent: Tuesday, May 16, 2017 6:08 AM
> To: Gert Grammel; Leeyoung; [e-mail]; [e-mail]
> Subject: Re: [Teas] terminology discussion network slicing
>
> Hi Gert,
>
> "Thinking a bit about it I came to the point where "VPN" and "network 
> slices" seem to describe the same entity or at least a "network slice"
> being a VPN of VPNs?"
>
> I share completely your conclusion , I'd like if someone can explain 
> if a difference really exists .
>
> Thanks
> Sergio
>
>
> -----Original Message-----
> From: Teas [mailto:[e-mail]] On Behalf Of Gert Grammel
> Sent: Monday, May 15, 2017 7:02 PM
> To: Leeyoung <[e-mail]>; [e-mail]; [e-mail]
> Subject: Re: [Teas] terminology discussion network slicing
>
> Leeyoung,
>
> Thank you for taking a stab on this. Usually when getting to a 
> definition, I try to establish what kind of existing constructs would 
> fall under the definition. If my understanding is correct, the 
> following list of constructs would all satisfy the definition somehow.
> - A TDM network with a p2p TDM connection
> - A PSC capable network carrying a p2p circuit (such as EPL/EVPL)
> - An MPLS LSP using a traffic engineered IP network
> - A L2VPN using a traffic engineered MPLS network
> - A L3VPN using a traffic engineered IP network
> - A TCP connection using a traffic engineered IP network
> - Different QoS classes in an IP network
>
> Thinking a bit about it I came to the point where "VPN" and "network 
> slices" seem to describe the same entity or at least a "network slice"
> being a VPN of VPNs?
>
> Gert
>
>
> On 2017-05-17, 16:44, "Teas on behalf of Leeyoung" 
> <[e-mail] on behalf of [e-mail]> wrote:
>
>     Hi Adrian and others,
>
>     We'd like cross check with you on some terminology we introduced newly. Any 
>     comment on these terms will be greatly appreciated.
>
>     We introduced 'network slicing' as follows:
>
>             Network slicing is a collection of resources
>             that are used to establish logically dedicated virtual networks
>             over TE networks. It allows a network provider to provide
>             dedicated virtual networks for application/customer over a
>             common network infrastructure. The logically dedicated
>             resources are a part of the larger common network
>             infrastructures that are shared among various network slice
>             instances which are the end-to-end realization of network
>             slicing, consisting of the combination of physically or
>             logically dedicated resources.
>
>
>     Thanks.
>     Young and Daniele
>     -----Original Message-----
>     From: Leeyoung
>     Sent: Friday, May 05, 2017 1:41 PM
>     To: [e-mail]
>     Subject: RE: [Teas] I-D Action: 
> draft-ietf-teas-actn-framework-05.txt
>
>     Hi,
>
>     This update is intended to incorporate the comments from the last WG 
>     meeting and any pending issues. We also have taken the global editorial 
>     changes to make it consistent through the document. Major changes are:
>
>     - Inclusion of "network slicing" definition from ACTN perspective (in the 
>     terminology section)
>     - Added virtual network service (VNS) section (Section 3) to define types 
>     of VNS.
>     - Incorporated "orchestration" (service/network) mapping to ACTN 
>     architecture (See Section 5.2)
>     - Created a new section 6 (Topology Abstraction Method) where we imported 
>     some texts from ACTN abstraction method  
>     https://tools.ietf.org/html/draft-lee-teas-actn-abstraction-01
>     - Added Appendices A & B to discuss example deployment scenarios such as 
>     example of MDSC and PNC functions integrated in Service/Network 
>     Orchestrator (Appendix A) and example of IP + Optical network with L3VPN 
>     service (Appendix B)
>
>     In regard to ACTN abstraction method draft, we are going to keep it as a 
>     separate draft and use this document to elaborate other aspects not 
>     imported to the framework document.
>
>     The following diff pointer will help you see the changes with this revision:
>     
> https://www.ietf.org/rfcdiff?url2=draft-ietf-teas-actn-framework-05
>
>     The co-authors believe that the document is ready for WG LC. Any 
>     changes/comments will be appreciated.
>
>     Thanks & Best regards,
>     Young & Daniele (on behalf of other co-authors/contributors)
>
>     -----Original Message-----
>     From: Teas [mailto:[e-mail]] On Behalf Of [e-mail]
>     Sent: Friday, May 05, 2017 10:41 AM
>     To: [e-mail]
>     Cc: [e-mail]
>     Subject: [Teas] I-D Action: draft-ietf-teas-actn-framework-05.txt
>
>
>     A New Internet-Draft is available from the on-line Internet-Drafts directories.
>     This draft is a work item of the Traffic Engineering Architecture and 
>     Signaling of the IETF.
>
>             Title           : Framework for Abstraction and Control of Traffic 
>             Engineered Networks
>             Authors         : Daniele Ceccarelli
>                               Young Lee
>     	Filename        : draft-ietf-teas-actn-framework-05.txt
>     	Pages           : 41
>     	Date            : 2017-05-05
>
>     Abstract:
>        Traffic Engineered networks have a variety of mechanisms to
>        facilitate the separation of the data plane and control plane. They
>        also have a range of management and provisioning protocols to
>        configure and activate network resources.  These mechanisms
>        represent key technologies for enabling flexible and dynamic
>        networking.
>
>        Abstraction of network resources is a technique that can be applied
>        to a single network domain or across multiple domains to create a
>        single virtualized network that is under the control of a network
>        operator or the customer of the operator that actually owns
>        the network resources.
>
>        This document provides a framework for Abstraction and Control of
>        Traffic Engineered Networks (ACTN).
>
>
>
>     The IETF datatracker status page for this draft is:
>     https://datatracker.ietf.org/doc/draft-ietf-teas-actn-framework/
>
>     There are also htmlized versions available at:
>     https://tools.ietf.org/html/draft-ietf-teas-actn-framework-05
>     
> https://datatracker.ietf.org/doc/html/draft-ietf-teas-actn-framework-0
> 5
>
>     A diff from the previous version is available at:
>     
> https://www.ietf.org/rfcdiff?url2=draft-ietf-teas-actn-framework-05
>
>
>     Please note that it may take a couple of minutes from the time of 
>     submission until the htmlized version and diff are available at tools.ietf.org.
>
>     Internet-Drafts are also available by anonymous FTP at:
>     ftp://ftp.ietf.org/internet-drafts/
>
>     _______________________________________________
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