Re: [Teas] [Teas-ns-dt] FW: The word "transport"

[Jeff Tantsura <[e-mail]>]

+1

Regards,
Jeff

> On May 1, 2020, at 11:13, LUIS MIGUEL CONTRERAS MURILLO <[e-mail]> wrote:
> 
> 
> Fully agree
>  
> De: Teas-ns-dt <[e-mail]> En nombre de Eric Gray
> Enviado el: viernes, 1 de mayo de 2020 19:54
> Para: John E Drake <[e-mail]>; Rokui, Reza (Nokia - CA/Ottawa) <[e-mail]>; [e-mail]; 'John E Drake' <jdrake=[e-mail]>; [e-mail]; [e-mail]
> Asunto: Re: [Teas-ns-dt] [Teas] FW: The word "transport"
>  
> Yes, the word “Transport” does carry a lot of baggage – here in the IETF and elsewhere.  Think of it as “baggage transport.” 😊
>  
> But that has not stopped us before.  You no doubt know what the “TP” stands for in MPLS-TP.
>  
> We cannot rule out use of terms that are pretty much in line with their English language interpretation, just because they are used ambiguously in another context, or in a general context.
>  
> I think that – if we were just calling it “Transport” – this would be a serious problem.  But we do not (AFAIK) use this in any context where we do not combine it with “Slicing” and we define “Transport Slicing.” Which should be enough to avoid issues with the fact that the separate terms are ambiguous.
>  
> Provided, of course, that it is sufficiently clear what we mean by “Transport Slicing.”
>  
> Quite frankly, I find it surprising that we are debating the terminology choices that were made by a design team at the working group level.  It is one thing if it can be argued that the choices are counter-intuitive – though I can think of numerous cases where that has not carried much weight.
>  
> What makes sense to discuss at the WG level is whether we define the terminology with sufficient clarity, and then use the terminology as we defined it.
>  
> --
> Eric
>  
> From: John E Drake <[e-mail]> 
> Sent: Friday, May 1, 2020 12:12 PM
> To: Rokui, Reza (Nokia - CA/Ottawa) <[e-mail]>; Eric Gray <[e-mail]>; [e-mail]; 'John E Drake' <jdrake=[e-mail]>; [e-mail]; [e-mail]
> Subject: RE: [Teas] FW: The word "transport"
> Importance: High
>  
> Hi,
>  
> That was not my understanding but if that’s true then we are responsible for developing a rather bad term.  As Adrian detailed in his original email, ‘transport’ is a term typically used by other standards bodies and that within the IETF it carries a lot of baggage.
>  
> Yours Irrespectively,
>  
> John
>  
>  
> Juniper Business Use Only
> From: Rokui, Reza (Nokia - CA/Ottawa) <[e-mail]> 
> Sent: Friday, May 1, 2020 11:56 AM
> To: John E Drake <[e-mail]>; Eric Gray <[e-mail]>; [e-mail]; 'John E Drake' <jdrake=[e-mail]>; [e-mail]; [e-mail]
> Cc: Rokui, Reza (Nokia - CA/Ottawa) <[e-mail]>
> Subject: Re: [Teas] FW: The word "transport"
>  
> [External Email. Be cautious of content]
>  
> >>>>> [JD]  This is back to Adrian’s original point, viz, ‘transport slice’ is a term coined by another standards body.
>  
> As far as I know there is not any SDO which defines “Transport slice” at least at the time that we wrote the draft. If not so, please provide the reference.
> We at IETF started using this term.
>  
> Reza
>  
> From: John E Drake <[e-mail]>
> Date: Friday, May 1, 2020 at 11:52 AM
> To: Reza Rokui <[e-mail]>, Eric Gray <[e-mail]>, "[e-mail]" <[e-mail]>, 'John E Drake' <jdrake=[e-mail]>, "[e-mail]" <[e-mail]>, "[e-mail]" <[e-mail]>
> Subject: RE: [Teas] FW: The word "transport"
>  
> Hi,
>  
> Comment inline
>  
> Yours Irrespectively,
>  
> John
>  
>  
> Juniper Business Use Only
> From: Teas-ns-dt <[e-mail]> On Behalf Of Rokui, Reza (Nokia - CA/Ottawa)
> Sent: Friday, May 1, 2020 11:49 AM
> To: Eric Gray <[e-mail]>; [e-mail]; 'John E Drake' <jdrake=[e-mail]>; [e-mail]; [e-mail]
> Cc: Rokui, Reza (Nokia - CA/Ottawa) <[e-mail]>
> Subject: Re: [Teas-ns-dt] [Teas] FW: The word "transport"
>  
> [External Email. Be cautious of content]
>  
> >>>>>>>> Possibly it would be better to clarify this in terms of what the IETF does deal with?
>  
> I meant that IETF does not address the other aspects of an e2e network slice like RAN and Core slice (aka Other Slices).
> A transport slice is just a piece of an e2e network slice. Any reference to “network slice” is not correct since IETF does not deal with Other Slices.
>  
> [JD]  This is back to Adrian’s original point, viz, ‘transport slice’ is a term coined by another standards body.
>  
> Reza Rokui, Ph.D.
> Director, NSP Product Management
> Nokia Canada
> IP/Optical Network Automation
> T:  [phone]
> M: [phone]
> 600 March Road, Kanata, Ontario, K2K 2E6
> [e-mail]
>  
>  
> From: Eric Gray <[e-mail]>
> Date: Friday, May 1, 2020 at 11:45 AM
> To: Reza Rokui <[e-mail]>, "[e-mail]" <[e-mail]>, 'John E Drake' <jdrake=[e-mail]>, "[e-mail]" <[e-mail]>, "[e-mail]" <[e-mail]>
> Subject: RE: [Teas] FW: The word "transport"
>  
> Possibly it would be better to clarify this in terms of what the IETF does deal with?
>  
> The IETF deals with “packetized” (more specifically, where packetization uses IETF defined packet formats) transport of otherwise arbitrary data.
>  
> Here you can replace transport with “carrying” – but this is essentially the standard English meaning of transport.
>  
> From: Teas-ns-dt <[e-mail]> On Behalf Of Rokui, Reza (Nokia - CA/Ottawa)
> Sent: Friday, May 1, 2020 11:38 AM
> To: [e-mail]; 'John E Drake' <jdrake=[e-mail]>; [e-mail]; [e-mail]
> Cc: Rokui, Reza (Nokia - CA/Ottawa) <[e-mail]>
> Subject: Re: [Teas-ns-dt] [Teas] FW: The word "transport"
>  
> Adrian,
>  
> >>>>>> I don’t understand “we (IETF) do not deal with network slice”.
>  
> Please refer to Figure 4 of the draft.
> In summary, an E2E network slice is the logical network from End user X to End use Y and comprises of:
> -          One or more Transport slices (TS)
> -          One or more Other Slices (OS)
>  
> Just as an example for “Other Slices”, in 5G these slices are RAN slices and 5G Core Slices.
> Referring  this Figure, it is clear that IETF deals with Transport slice which is part of an E2E network slice and “Other slices” are outside scope of IETF.
> Please make a clear distinction between Transport Slices and e2e network slices. They are different.
> IMHO, any reference to “Network Slice” in IETF drafts means “Transport slice” .
>  
> >>>>>>.  Why do we have a “TEAS Network Slicing Design Team”?
> Good question. The correct name can be “TEAS Transport Slicing Design Team”
>  
> <image001.png>
>  
> Reza
>  
>  
> From: Adrian Farrel <[e-mail]>
> Organization: Old Dog Consulting
> Reply-To: "[e-mail]" <[e-mail]>
> Date: Friday, May 1, 2020 at 10:30 AM
> To: Reza Rokui <[e-mail]>, 'John E Drake' <jdrake=[e-mail]>, "[e-mail]" <[e-mail]>, "[e-mail]" <[e-mail]>
> Subject: RE: [Teas] FW: The word "transport"
>  
> Hi Reza,
>  
> I don’t understand “we (IETF) do not deal with network slice”.
> Why do we have a “TEAS Network Slicing Design Team”?
>  
> Cheers,
> Adrian
>  
> From: Rokui, Reza (Nokia - CA/Ottawa) <[e-mail]> 
> Sent: 01 May 2020 15:13
> To: [e-mail]; 'John E Drake' <jdrake=[e-mail]>; [e-mail]; [e-mail]
> Cc: Rokui, Reza (Nokia - CA/Ottawa) <[e-mail]>
> Subject: Re: [Teas] FW: The word "transport"
>  
> John and all,
>  
> This is where I disagree with term “Underlay Network Slice”. It brings lots of other questions since we (IETF) do not deal with network slice as clearly described in our draft.
>  
> As I send in another email thread, as per Adrian’s suggestion, we define the term “Transport” as follows and would like to keep the term “Transport Slice”
>  
> Definition of term Transport: This term embraces various technologies such as IP, Optical, Ethernet, TDM, etc  that carry packets and traffic and might span multiple administrative domains.
>  
> Please provide your suggestion to refine this definition.
>  
> Cheers,
> Reza
>  
> From: Adrian Farrel <[e-mail]>
> Organization: Old Dog Consulting
> Reply-To: "[e-mail]" <[e-mail]>
> Date: Friday, May 1, 2020 at 5:23 AM
> To: 'John E Drake' <jdrake=[e-mail]>, Reza Rokui <[e-mail]>
> Cc: "[e-mail]" <[e-mail]>
> Subject: RE: [Teas] FW: The word "transport"
>  
> Yeah, ‘underlay’ seems good because it is a relative term and usefully recursive.
>  
> A
>  
> From: Teas <[e-mail]> On Behalf Of John E Drake
> Sent: 30 April 2020 20:59
> To: [e-mail]; 'Rokui, Reza (Nokia - CA/Ottawa)' <[e-mail]>
> Cc: [e-mail]
> Subject: Re: [Teas] FW: The word "transport"
>  
> Hi,
>  
> How about ‘underlay network slice’?  It’s describing exactly what we are doing and is congruent with the Enhanced VPN draft.
>  
> Yours Irrespectively,
>  
> John
>  
>  
> Juniper Business Use Only
> From: Teas <[e-mail]> On Behalf Of Adrian Farrel
> Sent: Thursday, April 30, 2020 3:32 PM
> To: 'Rokui, Reza (Nokia - CA/Ottawa)' <[e-mail]>
> Cc: [e-mail]
> Subject: [Teas] FW: The word "transport"
>  
> [External Email. Be cautious of content]
>  
> Reza,
>  
> Thanks for forwarding this email.
>  
> I appreciate and understand the way that 3GPP use the term “transport”. It makes a lot of sense in the 3GPP context: they are talking about connectivity in their realm, and anything that provides that connectivity (such as an IP network) counts as “transport”.
>  
> But we are not the 3GPP and our terminology needs to be consistent. As I noted, we already have multiple meanings of transport:
> -          The transport layer (traditional from the OSI model) that includes TCP, UDP, etc.
> -          Transport networks (a term also used in the ITU-T) that embraces Ethernet, TDM, and optical technologies that carry packets for us. This term is most often seen in CCAMP, TEAS, and PCE.
> -          MPLS-TP (possibly deriving from the ITU-T’s T-MPLS) that refers to the use of MPLS as a technology to build transport networks as described in the previous bullet
> -          Transport as a verb (such as in HTTP) meaning simply ‘to carry’
> In the ACTN work, we moved from ‘transport’ to ‘TE’ recognising that ACTN was applicable to any network type where paths could be computed and imposed, and resource partitioned and reserved.
>  
> Now, you say Transport networks (which are technology specific) are used to realized “Transport Slices” which would appear to imply that IP cannot be used to realise a transport slice. I don’t know if that is your intention.
>  
> You also say They [3GPP] did not define anything related to Transport but you say that immediately under a figure you have copied from 3GPP TS 28.530 that clearly shows transport slices, so that leaves me more than a little confused.
>  
> Additionally, you say…
> VPN is one of the  solutions to realize the transport slices in IP networks.
> …which is fine by me since I am not (here) talking about solutions but services. Actually, I think you would do well to distinguish between VPN as a service and the technologies used to realise a VPN.
>  
> Then…
> However, The idea of Transport Slice is to allow a high-level system (or consumer or an Orchestrator) to ask for a various connections (i.e. Transport slices)
> … This is pretty meaningless the way you have worded it. You have said “the idea of a transport slice is to all a request for transport slices...
> across  IP, Optics, PON, Microwave or any combination of these networks. We shall not limit ourselves to IP VPN.
> …Yes, indeed. I wonder where the idea of such a limitation came from…
> Note that the definition of the Transport slice is technology agnostic.
> …I know. It comes from draft-ietf-teas-enhanced-vpn. That originated in draft-king-teas-applicability-actn-slicing. I believe I drafted it…
> [snip]
> In summary, since the connectivity between various endpoints are across transport network (i.e. IP, Optics, PON, Microware etc.), it is logical to assume the Connections are called Transport Slice.
> …which is fine except that you have moved the problem to the definition of “transport network”. The IETF will struggle, I think, with the idea that an IP network is a transport network unless, in the context of these documents, you give a very clear explanation of what these documents mean by that term.
>  
> But perhaps we can cut through all of this with some simple clarity. Text to describe the context and meaning of ‘transport’. Since the terminology document has so cheerfully plundered the enhanced VPN framework draft for some text, you might look there (in the Introduction) for suitable context-setting text.
>  
> That, of course, leads me to a separate question that I have, which is why the design team is reproducing and/or copying material from an existing WG document rather than working with that document to refine it and/or split it into multiple documents. A different question, but one the chairs might like to comment on.
>  
> Best,
> Adrian
>  
> From: Teas-ns-dt <[e-mail]> On Behalf Of Rokui, Reza (Nokia - CA/Ottawa)
> Sent: 30 April 2020 16:23
> To: [e-mail]; [e-mail]
> Cc: Rokui, Reza (Nokia - CA/Ottawa) <[e-mail]>
> Subject: [Teas-ns-dt] FW: The word "transport"
>  
> All,
>  
> I thought I sent this to TEAS and TEAS-NS-DT team before. Forwarding the response to everyone.
>  
> Cheers,
> Reza
>  
>  
>  
> From: Reza Rokui <[e-mail]>
> Date: Saturday, April 25, 2020 at 11:37 PM
> To: Dhruv Dhody <[e-mail]>, Jari Arkko <[e-mail]>, "[e-mail]" <[e-mail]>
> Cc: Reza Rokui <[e-mail]>
> Subject: Re: The word "transport"
>  
> Hi all,
>  
> Please see inline for some clarifications.
>  
> Reza
>  
>  
> On 2020-04-24, 1:31 AM, "Dhruv Dhody" <[e-mail]> wrote:
>  
>     Hi Reza,
>  
>     I am putting the relevant text here -
>  
>     ==
>  
>     [14:28:42] <adrianfarrel> I'm getting very confused by everyone
>     talking about "transport networks" and "transport slices". Is this
>     something coming out of 3GPP?
>  
> [Reza] Please note that the “Transport Slice” from IETF point of view is not only limited to 5G network slicing.
> 5G network slicing is just one use-case of transport slicing as described in Transport Slice definition draft.
>  
> Regarding 5G use-case, the following figure is taken from 3GPP TS 28.530 where the “Transport slice” is described as “Connectivity” across transport network.
> This is the reason that what has been described in our draft for “Transport Slices” is a set of Connections between various endpoints with certain SLOs.
> Note that 3GPP did not define the Transport slice explicitly.
>  
> <image004.png>
>  
>  
>  
>     [14:29:06] <adrianfarrel> Seems to me that we (for example, ACTN) went
>     through a lot to clarify that "transport network" was sub-IP
>     [14:29:17] <adrianfarrel> ...maybe even sub-MPLS
> [Reza] Transport networks (which are technology specific) are used to realized “Transport Slices”. Please see draft for more info.
>  
>     [14:31:39] <Joel Halpern> "Transport Network" is the industry
>     terminology for the network that connects the radio (and related gear)
>     to the packet core (and related gear).
>     [14:32:03] <Joel Halpern> It is indeed a different usage.  I wish it
>     were not overloading.  But they didn't ask me.
>     [14:32:47] <Joel Halpern> Which part it refers to in a fixed access
>     network is even less clear.
>  
> [Reza] The following figure is taken from 3GPP TS 28.530 where it shows various “Transport slices”.
> Note that the “Transport Slices” are not only used for RAN to Core. Depends on the deployment, we can have
> Transport slices in RAN for midhaul and fronthaul, in 5G Core or for application. All these transport slices are shown below.
>  
> ]
> <image005.png>
>  
>     [14:39:54] <adrianfarrel> I understand why 3GPP uses the term. I don't
>     understand why we use the term.. We could talk about 'Foobar slices'
>     and add one line that says "In the 3GPP, the term 'Transport Slice' is
>     used for what we call a 'Foobar Slice'."
> [Reza]  Note that 3GPP used the term “slice subnet” when describing it in context of 5G Core and RAN (i.e Core Slice Subnet and RAN Slice Subnet).
> They did not define anything related to Transport. As indicated above, 3GPP refer it to “Connectivity”.
> We did not want to use Subnet because in IP,  subnet has a very clear definition and using term “Transport Subnet” is completely misleading. So, we chose Transport Slice.
> Also since the connectivity between various endpoints are across transport network (i.e. IP, Optics, PON, Microware etc.), it is logical to assume the Connections are called Transport Slice.
>  
>  
>     [14:40:18] <adrianfarrel> We *already* have two definitions of
>     "transport" in the IETF. We really don't need three
> [Reza] Please provide links to these two definition.
>  
>     [14:59:00] <adrianfarrel> Well, I picked "foobar' in order to not jump
>     immediately to a strawman solution. I think we are talking about
>     providing slices as a service across the Internet. Same level of entry
>     as a VPN: that is, the consumer provides a packet stream to the
>     service entry point, and expects the packets to be delivered to the
>     service exit point. Obviously, the consumer of the service may see the
>     service as a transport (cf. pseudowires), but we would be 'alarmed' to
>     hear a L3VPN described as a 'transport VPN.'
> [Reza] VPN is one of the  solutions to realize the transport slices in IP networks.
> However, The idea of Transport Slice is to allow a high-level system (or consumer or an Orchestrator) to ask for a various connections (i.e. Transport slices) across  IP, Optics, PON, Microwave or any combination of these networks. We shall not limit ourselves to IP VPN.
> Note that the definition of the Transport slice is technology agnostic. For example in 5G you can realize a transpot slice in midhaul (please refer to picture above) which is a set of connections between 5G RAN nodes using PON or Optical connection. In this case there is no IP VPN.
> In summary, since the connectivity between various endpoints are across transport network (i.e. IP, Optics, PON, Microware etc.), it is logical to assume the Connections are called Transport Slice.
>  
>     Full logs - https://www.ietf.org/jabber/logs/teas/2020-04-23.html
>  
>     ==
>  
>     More inline..
>  
>     On Thu, Apr 23, 2020 at 10:27 PM Rokui, Reza (Nokia - CA/Ottawa)
>     <[e-mail]> wrote:
>     >
>     > Hi Dhruv,
>     >
>     > As far as I remember, we did not have any argument about term "transport". It was agreed that the term "Transport" is suited in context of network slicing.
>     > The initial discussion was "Transport network slicing" which later we agreed to remove "network" since it causes confusion since IETF do not cover the e2e network slicing but rather the transport part.
>     >
>     > I was not clear about Adrian's comment regarding term "transport". IMHO, this term is well suited since it convers any underlying technology for L0 to L3.
>     >
>  
>     In CCAMP/TEAS circles, the transport network term might not be used
>     for L3 (and thus the confusion). And then there are the Transport
>     Protocols! Definition draft should include some clarity on what do we
>     mean when we say transport network at the least!
>  
>     It would be good to get this resolved sooner as we develop multiple
>     documents that uses the same terminology!
>  
>     Thanks!
>     Dhruv
>  
>     > Reza
>     >
>     >
>     > On 2020-04-23, 12:35 PM, "Dhruv Dhody" <[e-mail]> wrote:
>     >
>     >     Hi,
>     >
>     >     Adrian gave some comments on jabber about using the word "transport".
>     >
>     >     During RFC8453 devolpment, this came up where TN in ACTN was transport
>     >     networks and it was changed to TE networks to avoid using the
>     >     overloaded term "transport".
>     >
>     >     We need to find a way to justify using this term and maybe describe
>     >     this more in the definition draft - and just saying that 3GPP uses
>     >     that term may not work I guess!
>     >
>     >     Was this discussed in the design team earlier, i joined the effort
>     >     much later.
>     >
>     >     Thanks!
>     >     Dhruv
>     >
>  
> Juniper Business Use Only
>  
> Juniper Business Use Only
>  
> Juniper Business Use Only
> 
> 
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