Re: [Teas] [E] Re: Slicing Framework Open issue #1 : Service != Realization

Joel Halpern <jmh@joelhalpern.com> Wed, 18 May 2022 19:25 UTC

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To: Krzysztof Szarkowicz <kszarkowicz@gmail.com>, "Dongjie (Jimmy)" <jie.dong@huawei.com>, John E Drake <jdrake@juniper.net>, "adrian@olddog.co.uk" <adrian@olddog.co.uk>, mohamed.boucadair@orange.com
Cc: "teas@ietf.org" <teas@ietf.org>
References: <042601d84029$1de567c0$59b03740$@olddog.co.uk> <501D30C7-5DE7-45E9-86EC-0A6665319F02@gmail.com> <2d25ec2c0b164146aeadb09aadcfa66b@huawei.com> <DF539A34-AD85-4666-9704-EB7EA8B3BA1A@gmail.com> <411896c7b1c94b4997dca596df3828bf@huawei.com> <333A778F-B542-4CD6-80B5-0FD639DE2C44@gmail.com> <621779c1e05c48eda022dc051d182f9d@huawei.com> <B67E6A59-1878-462F-8D5A-AB027051274F@gmail.com> <2e60088e815d4081a71bede289f752ae@huawei.com> <756B77A9-B393-4FEA-A25D-224A9097D4D5@gmail.com> <aa1fcaa639ce4aed8555a0513fe2c59e@huawei.com> <BY3PR05MB8081EE86385E627E2BF4E9C8C7FA9@BY3PR05MB8081.namprd05.prod.outlook.com> <8601ab681f5c415bb0a1eaaf9c0f2576@huawei.com> <BY3PR05MB8081D3CFB2F1B47EE47878BBC7FD9@BY3PR05MB8081.namprd05.prod.outlook.com> <3f314d1be1c54ac6bc4d4cd4a6e833f8@huawei.com> <BY3PR05MB80814A03CBB3954501AF2CA5C7FD9@BY3PR05MB8081.namprd05.prod.outlook.com> <921D62D1-CB07-49FC-BD46-E7E1A1DDD31D@gmail.com> <F7E81387-F400-4680-9589-B81535723E59@gmail.com>
From: Joel Halpern <jmh@joelhalpern.com>
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Subject: Re: [Teas] [E] Re: Slicing Framework Open issue #1 : Service != Realization
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I mostly like that.  But there is a dimension that I am having trouble 
mapping to the text you provide.


The case that persuaded me to get interested in NRP in the first place 
was queueing resources.  (Specifically, the fact that for SR-MPLS the 8 
diffserv code points are not enough to represent the needed range of 
queueing behaviors.)  How does that relate to the text you have below?  
It has little or nothing to do with the topology.


Yours,

Joel

On 5/18/2022 3:16 PM, Krzysztof Szarkowicz wrote:
> Hi,
>
> So, do we have agreement for following change:
>
>
>           An NRP is simply a collection of resources identified in the 
> underlay network. The amount and granularity of resources allocated in 
> different portions of an NRP can be flexible. Depends on the 
> operator’s policy and the service requirements, some NRP realizations 
> may build the NRPs with dedicated topologies, while some other 
> realizations may allow shared topology for multiple NRPs, one possible 
> case is that the entire underlay network topology is used by all the 
> NRPs. Some realization might as well use single NRP only with the 
> resources of the entire underlay network topology.
>
> Best regards,
> Krzysztof
>
>
>> On 2022 -Apr-29, at 14:57, Krzysztof Szarkowicz 
>> <kszarkowicz@gmail.com> wrote:
>>
>> So,
>>
>> Are we OK now? From my perspective it look good.
>>
>> Best regards,
>> Krzysztof
>>
>>
>>> On 2022 -Apr-28, at 16:58, John E Drake <jdrake@juniper.net> wrote:
>>>
>>> And I think it’s incorrect
>>> Yours Irrespectively,
>>> John
>>> Juniper Business Use Only
>>> *From:*Dongjie (Jimmy) <jie.dong@huawei.com>
>>> *Sent:*Thursday, April 28, 2022 10:57 AM
>>> *To:*John E Drake <jdrake@juniper.net>; Krzysztof Szarkowicz 
>>> <kszarkowicz@gmail.com>
>>> *Cc:*adrian@olddog.co.uk; <mohamed.boucadair@orange.com> 
>>> <mohamed.boucadair@orange.com>;teas@ietf.org
>>> *Subject:*RE: [Teas] [E] Re: Slicing Framework Open issue #1 : 
>>> Service != Realization
>>> *[External Email. Be cautious of content]*
>>> Hi John,
>>> The sentence you quoted was the last sentence in Krzysztof ‘s 
>>> proposal, and I just reused it in my proposed text:
>>> “… where the entire underlay network topology is used by all NRPs.”
>>> Best regards,
>>> Jie
>>> *From:*John E Drake [mailto:jdrake@juniper.net 
>>> <mailto:jdrake@juniper.net>]
>>> *Sent:*Thursday, April 28, 2022 8:28 PM
>>> *To:*Dongjie (Jimmy) <jie.dong@huawei.com>; Krzysztof Szarkowicz 
>>> <kszarkowicz@gmail.com>
>>> *Cc:*adrian@olddog.co.uk; <mohamed.boucadair@orange.com> 
>>> <mohamed.boucadair@orange.com>;teas@ietf.org
>>> *Subject:*RE: [Teas] [E] Re: Slicing Framework Open issue #1 : 
>>> Service != Realization
>>> The text that I thought was incorrect:  “, one possible case is that 
>>> the entire underlay network topology is used by all the NRPs.”
>>> Yours Irrespectively,
>>> John
>>> Juniper Business Use Only
>>> *From:*Dongjie (Jimmy) <jie.dong@huawei.com>
>>> *Sent:*Thursday, April 28, 2022 12:56 AM
>>> *To:*John E Drake <jdrake@juniper.net>; Krzysztof Szarkowicz 
>>> <kszarkowicz@gmail.com>
>>> *Cc:*adrian@olddog.co.uk; <mohamed.boucadair@orange.com> 
>>> <mohamed.boucadair@orange.com>;teas@ietf.org
>>> *Subject:*RE: [Teas] [E] Re: Slicing Framework Open issue #1 : 
>>> Service != Realization
>>> *[External Email. Be cautious of content]*
>>> Hi John,
>>> My understanding is that when NRP is introduced to the network for 
>>> supporting IETF network slices, there would be at least two NRPs. 
>>> Only one NRP with the entire underlay network topology would be same 
>>> thing as the underlay network, do we need to call it an NRP?
>>> Besides, the text I proposed is general and can even apply to the 
>>> “one NRP” case you mentioned.
>>> Best regards,
>>> Jie
>>> *From:*John E Drake [mailto:jdrake@juniper.net 
>>> <mailto:jdrake@juniper.net>]
>>> *Sent:*Wednesday, April 27, 2022 9:15 PM
>>> *To:*Dongjie (Jimmy) <jie.dong@huawei.com>; Krzysztof Szarkowicz 
>>> <kszarkowicz@gmail.com>
>>> *Cc:*adrian@olddog.co.uk; <mohamed.boucadair@orange.com> 
>>> <mohamed.boucadair@orange.com>;teas@ietf.org
>>> *Subject:*RE: [Teas] [E] Re: Slicing Framework Open issue #1 : 
>>> Service != Realization
>>> Hi,
>>> I don’t think the text identified with [jie#4} is correct, because 
>>> in the limiting case there is only one NRP and it consists of the 
>>> entire underlay network topology.  I think this was what Krzysztof 
>>> and Med were noting, and adding a simple statement of this in the 
>>> Framework draft would make sense.
>>> Yours Irrespectively,
>>> John
>>> Juniper Business Use Only
>>> *From:*Dongjie (Jimmy) <jie.dong@huawei.com>
>>> *Sent:*Wednesday, April 27, 2022 5:52 AM
>>> *To:*Krzysztof Szarkowicz <kszarkowicz@gmail.com>
>>> *Cc:*John E Drake <jdrake@juniper.net>;adrian@olddog.co.uk; 
>>> <mohamed.boucadair@orange.com> 
>>> <mohamed.boucadair@orange.com>;teas@ietf.org
>>> *Subject:*RE: [Teas] [E] Re: Slicing Framework Open issue #1 : 
>>> Service != Realization
>>> *[External Email. Be cautious of content]*
>>> Hi Krzysztof,
>>> Please see inline [Jie #4]:
>>> *From:*Krzysztof Szarkowicz [mailto:kszarkowicz@gmail.com 
>>> <mailto:kszarkowicz@gmail.com>]
>>> *Sent:*Tuesday, April 26, 2022 2:47 PM
>>> *To:*Dongjie (Jimmy) <jie.dong@huawei.com>
>>> *Cc:*John E Drake <jdrake@juniper.net>;adrian@olddog.co.uk; 
>>> <mohamed.boucadair@orange.com> 
>>> <mohamed.boucadair@orange.com>;teas@ietf.org
>>> *Subject:*Re: [Teas] [E] Re: Slicing Framework Open issue #1 : 
>>> Service != Realization
>>> Hi Jie,
>>> Please see inline [Krzysztof #3]
>>>
>>>     On 2022 -Apr-26, at 05:18, Dongjie (Jimmy) <jie.dong@huawei.com>
>>>     wrote:
>>>     Hi Krzysztof,
>>>     Please see inline [Jie #3]:
>>>     *From:*Krzysztof Szarkowicz [mailto:kszarkowicz@gmail.com
>>>     <mailto:kszarkowicz@gmail.com>]
>>>     *Sent:*Tuesday, April 26, 2022 4:58 AM
>>>     *To:*Dongjie (Jimmy) <jie.dong@huawei.com
>>>     <mailto:jie.dong@huawei.com>>
>>>     *Cc:*John E Drake <jdrake@juniper.net
>>>     <mailto:jdrake@juniper.net>>;adrian@olddog.co.uk
>>>     <mailto:adrian@olddog.co.uk>; <mohamed.boucadair@orange.com
>>>     <mailto:mohamed.boucadair@orange.com>>
>>>     <mohamed.boucadair@orange.com
>>>     <mailto:mohamed.boucadair@orange.com>>;teas@ietf.org
>>>     <mailto:teas@ietf.org>
>>>     *Subject:*Re: [Teas] [E] Re: Slicing Framework Open issue #1 :
>>>     Service != Realization
>>>     Hi Jie,
>>>     Please see inline [Krzysztof #2]
>>>
>>>         On 2022 -Apr-21, at 09:41, Dongjie (Jimmy)
>>>         <jie.dong@huawei.com <mailto:jie.dong@huawei.com>> wrote:
>>>         Hi Krzysztof,
>>>         Please see inline with [Jie #2]:
>>>         *From:*Krzysztof Szarkowicz [mailto:kszarkowicz@gmail.com
>>>         <mailto:kszarkowicz@gmail.com>]
>>>         *Sent:*Wednesday, April 20, 2022 11:23 PM
>>>         *To:*Dongjie (Jimmy) <jie.dong@huawei.com
>>>         <mailto:jie.dong@huawei.com>>
>>>         *Cc:*John E Drake <jdrake@juniper.net
>>>         <mailto:jdrake@juniper.net>>;adrian@olddog.co.uk
>>>         <mailto:adrian@olddog.co.uk>; <mohamed.boucadair@orange.com
>>>         <mailto:mohamed.boucadair@orange.com>>
>>>         <mohamed.boucadair@orange.com
>>>         <mailto:mohamed.boucadair@orange.com>>;teas@ietf.org
>>>         <mailto:teas@ietf.org>
>>>         *Subject:*Re: [Teas] [E] Re: Slicing Framework Open issue #1
>>>         : Service != Realization
>>>         Hi Jie,
>>>         Please see inline.
>>>         Thanks,
>>>         Krzysztof
>>>
>>>             On 2022 -Apr-20, at 10:31, Dongjie (Jimmy)
>>>             <jie.dong@huawei.com <mailto:jie.dong@huawei.com>> wrote:
>>>             Hi Krzysztof,
>>>             Please see some replies inline:
>>>             *From:*Krzysztof Szarkowicz
>>>             [mailto:kszarkowicz@gmail.com
>>>             <mailto:kszarkowicz@gmail.com>]
>>>             *Sent:*Tuesday, April 19, 2022 12:17 AM
>>>             *To:*Dongjie (Jimmy) <jie.dong@huawei.com
>>>             <mailto:jie.dong@huawei.com>>
>>>             *Cc:*John E Drake <jdrake@juniper.net
>>>             <mailto:jdrake@juniper.net>>;adrian@olddog.co.uk
>>>             <mailto:adrian@olddog.co.uk>;
>>>             <mohamed.boucadair@orange.com
>>>             <mailto:mohamed.boucadair@orange.com>>
>>>             <mohamed.boucadair@orange.com
>>>             <mailto:mohamed.boucadair@orange.com>>;teas@ietf.org
>>>             <mailto:teas@ietf.org>
>>>             *Subject:*Re: [Teas] [E] Re: Slicing Framework Open
>>>             issue #1 : Service != Realization
>>>             Hi Jie,
>>>             I still see tight coupling between NRP and the topology.
>>>             There will be realizations that do not use topology
>>>             filtering (i.e, multiple NRPs use the same topology ->
>>>             potentially entire network), so I am not sure, why
>>>             realization with coupling between topology and NRP is so
>>>             emphasized, while other realizations are not.
>>>             [Jie] Totally agree that multiple NRPs can share the
>>>             same topology, and as you said one extreme case is that
>>>             the NRPs are created using the base topology of the
>>>             network. While in any of these cases, an NRP needs to be
>>>             associated with a topology to determine the set of links
>>>             and nodes involved for resource management/reservation
>>>             and path computation of the NRP.
>>>             That said, I agree that topology filtering is just one
>>>             optional approach to determine the topology of the NRP,
>>>             and may not need to be highlighted in the text.
>>>             What about following text (or something like that):
>>>             An NRP is simply a collection of resources identified in
>>>             the underlay network. The details about tracked
>>>             resources might depend on NRP realization. Some NRP
>>>             realizations might put more focus on transport access
>>>             resources, while some other NRP realizations might focus
>>>             on transport core, or both transport access and
>>>             transport core resources. Furthermore, some NRP
>>>             realizations might build on tight coupling of an NRP
>>>             with underlying filtered topology, while some other NRP
>>>             realizations might not use separate filtered topologies
>>>             at all. The framework is open for different NRP
>>>             realizations, but the details of these realizations are
>>>             out of scope for this document.
>>>             [Jie] I’m not sure whether it is needed to mention
>>>             access/core as they are only applicable to specific
>>>             network types. And the term transport has been proved
>>>             controversial in the past.
>>>
>>>         [Krzysztof] I am OK to change the terms for something
>>>         different, to be more technology agnostic. What I would like
>>>         to see as the outcome of the framework document is, that
>>>         different NRP realizations might have different focus on
>>>         then granularity of resource tracking in different part of
>>>         the underlay network. I.e.,  as a simple example, in case of
>>>         packet switched network as the underlay technology,
>>>         realizing e.g. P2P service slice might be achieved by kind
>>>         of converting the packet switched network to circuit
>>>         switched network (with granular tracking of resources across
>>>         the entire path used for service delivery), but some other
>>>         realization of such P2P service might only track the
>>>         resources with high granularity at the access (AC), and use
>>>         other techniques in other parts of the network to realize
>>>         the service.
>>>         I see the framework document should address that, without
>>>         calling any technology details.
>>>         [Jie #2] I can understand your point that the amount and
>>>         granularity of resource management/reservation (I guess it
>>>         is what your called resource tracking) for an NRP does not
>>>         have to be the same everywhere, aggregation or sharing with
>>>         certain criteria could be allowed.
>>>
>>>      [Krzysztof #2] Indeed. Moreother, some NRP realizations might
>>>     focus (=more granular resource management/reservation) in part
>>>     ‘X’of the network, while less granular in part Y,
>>>     whole some other NRP realization just to the opposite -
>>>     more granular in part Y, while less granular in part X. I see
>>>     this should be somehow captured in the framework.
>>>     [Jie #3] I think there could some text about the different
>>>     granularity of resources for NRPs.
>>>
>>> [Krzysztof #3] I proposed some text regarding to this referring 
>>> to’transport access’and’transport core’. You didn’t liked this 
>>> terms. So, can you propose some text?
>>> [Jie #4] How about some text like this:
>>>           An NRP is simply a collection of resources identified in 
>>> the underlay network. The amount and granularity of resources 
>>> allocated in different portions of an NRP can be flexible. Depends 
>>> on the operator’s policy and the service requirements, some NRP 
>>> realizations may build the NRPs with dedicated topologies, while 
>>> some other realizations may allow shared topology for multiple NRPs, 
>>> one possible case is that the entire underlay network topology is 
>>> used by all the NRPs.
>>>
>>>             Regarding the relationship between NRP and topology,
>>>             here is my suggested text:
>>>                Depends on the operator’s policy and the service
>>>             requirements, some NRP realizations may build the NRPs
>>>             with dedicated topologies, while some other realizations
>>>             may use shared topology for multiple NRPs, one extreme
>>>             of which is to use the entire underlay network topology
>>>             for the NRPs.
>>>
>>>         [Krzysztof] What about following text:
>>>          Depends on the operator’s policy and the service
>>>         requirements, some NRP realizations may build the NRPs with
>>>         dedicated topologies, while some other realizations may use
>>>         shared topology for multiple NRPs. Some realizations might
>>>         even not use NRP topology differentiation at all, where the
>>>         entire underlay network topology is used by all NRPs.
>>>         [Jie #2] I see we are converging on this. The remaining
>>>         small difference is whether all NRPs built on the entire
>>>         underlay network topology can be seen as a special case of
>>>         “multiple NRPs sharing the same topology”.
>>>         The main point of this text is an NRP is associated with a
>>>         topology, which can be either a dedicated topology or a
>>>         shared topology, and can be either a sub-topology or the
>>>         entire underlay network topology.
>>>         Thus I’d prefer an description with enough generality, then
>>>         the special case could be described under the general
>>>         statement. What do you think?
>>>
>>>     [Krzysztof #2] I am nart sure, what text are you proposing.
>>>     [Jie #3] The generic text I propose is similar to what is in my
>>>     previous mail:
>>>     Depends on the operator’s policy and the service requirements,
>>>     some NRP realizations may build the NRPs with dedicated
>>>     topologies, while some other realizations may allow shared
>>>     topology for multiple NRPs, one extreme case is that the entire
>>>     underlay network topology is used by all the NRPs.
>>>
>>> [Krzysztof #3] What is‘extreme’for one realization, can be 
>>> considered as’normal’(default) for another realization. So, my 
>>> proposed text was avoiding such verbiage.
>>> [Jie #4] In my understanding, “each NRP with separated topologies” 
>>> and “all NRPs with the same topology” are the two extremes of the 
>>> solution space. And please see the modified text in reply to your 
>>> last comment.
>>> Best regards,
>>>
>>> Jie
>>>
>>>     Please note that using shared topology for multiple NRPs is
>>>     considered as one optimization approach in
>>>     draft-dong-teas-nrp-scalability.
>>>     Best regards,
>>>
>>>     Jie
>>>
>>>         Best regards,
>>>
>>>         Jie
>>>
>>>             Best regards,
>>>             Jie
>>>             Best regards,
>>>
>>>             Krzysztof
>>>
>>>                 On 2022 -Apr-18, at 12:18, Dongjie (Jimmy)
>>>                 <jie.dong@huawei.com <mailto:jie.dong@huawei.com>>
>>>                 wrote:
>>>                 Hi Krzysztof,
>>>                 Thanks for your reply. Please see some further
>>>                 inline with [Jie]:
>>>                 *From:*Krzysztof Szarkowicz
>>>                 [mailto:kszarkowicz@gmail.com
>>>                 <mailto:kszarkowicz@gmail.com>]
>>>                 *Sent:*Friday, April 15, 2022 3:01 PM
>>>                 *To:*Dongjie (Jimmy) <jie.dong@huawei.com
>>>                 <mailto:jie.dong@huawei.com>>
>>>                 *Cc:*John E Drake <jdrake@juniper.net
>>>                 <mailto:jdrake@juniper.net>>;adrian@olddog.co.uk
>>>                 <mailto:adrian@olddog.co.uk>;
>>>                 <mohamed.boucadair@orange.com
>>>                 <mailto:mohamed.boucadair@orange.com>>
>>>                 <mohamed.boucadair@orange.com
>>>                 <mailto:mohamed.boucadair@orange.com>>;teas@ietf.org
>>>                 <mailto:teas@ietf.org>
>>>                 *Subject:*Re: [Teas] [E] Re: Slicing Framework Open
>>>                 issue #1 : Service != Realization
>>>                 Hi Jie,
>>>                 Thank you for fast response.
>>>                 I fully agree with you, that the realization is the
>>>                 combination of various techniques, and in particular
>>>                 realization, there could be more focus on some
>>>                 technique‘A’, while in some other realization there
>>>                 could be some more focus on technique‘B’. And, the
>>>                 framework should be open for different realizations.
>>>                 [Jie] Agree the framework should be open to
>>>                 different realizations, and this is my understanding
>>>                 about the NRP description in the framework draft.
>>>                 I have re-read section 6.1, I am still confused with
>>>                 the first paragraph on page 30, which says:
>>>                    An NRP is simply a collection of resources
>>>                 identified in the underlay
>>>                    network.  Thus, the NRP is a scoped view of a
>>>                 topology and may be
>>>                    considered as a topology in its own right.  The
>>>                 process of
>>>                    determining the NRP may be made easier if the
>>>                 underlay network
>>>                    topology is first filtered into a Filter Topology
>>>                 in order to be
>>>                    aware of the subset of network resources that are
>>>                 suitable for
>>>                    specific NRPs, but this is optional.
>>>                 It is very tight coupling between NRP and the
>>>                 topology. IMHO, is some realizations this tight
>>>                 coupling might be true, I’m some realizations it
>>>                 might not be true. This paragraph is most
>>>                 distracting for me.
>>>                 [Jie] My understanding about the topology here is
>>>                 that it is a generic term used to represent the set
>>>                 of network nodes and links that belong to the NRP,
>>>                 it does not constrain any mechanism to build or
>>>                 select the topology.
>>>                 But I agree the text could be improved. My
>>>                 suggestion is something like:
>>>                 An NRP is simply a collection of resource identified
>>>                 in the underlay network. The set of nodes and links
>>>                 belonging to the NRP provide the scoped view of a
>>>                 topology, and the NRP may be considered as a
>>>                 topology in its own right.
>>>                 The rest text about filter topology (or call it
>>>                 sub-topology) is considered optional and I’m fine to
>>>                 either remove it or keep it.
>>>                 Best regards,
>>>                 Jie
>>>                 Best regards,
>>>                 Krzysztof
>>>
>>>                     On 2022 -Apr-15, at 07:00, Dongjie (Jimmy)
>>>                     <jie.dong@huawei.com
>>>                     <mailto:jie.dong@huawei.com>> wrote:
>>>                     Hi Krzysztof,
>>>                     Yes NRP is a concept introduced for the
>>>                     realization of IETF network slice, and it is the
>>>                     result of long time WG discussion about the
>>>                     terminology for the underlay network construct
>>>                     which is used to support the IETF network slice
>>>                     services. My personal understanding is that the
>>>                     NRP concept and definition belongs to the
>>>                     framework document, while the technologies used
>>>                     to instantiate NRP are out of its scope. For
>>>                     sure there can be multiple ways to build an NRP,
>>>                     as long as they comply to the NRP definition in
>>>                     the framework.
>>>                     I understand your concern is whether the
>>>                     framework mandates only one or two mechanisms to
>>>                     build NRP, I don’t think this is what the
>>>                     current framework indicates. Thus to me the
>>>                     examples about detailed realization mechanisms
>>>                     are not quite necessary for the framework
>>>                     document and may contradict with its role as a
>>>                     high-level framework.
>>>                     On the other hand, discussion about the possible
>>>                     mechanisms to build NRPs can continue in the WG.
>>>                     To me an NRP is usually realized with the
>>>                     combination of a set of data plane and control
>>>                     plane technologies. Constrained path computation
>>>                     or Flex-Algo can only be seen as a component
>>>                     rather than a complete solution. As you
>>>                     mentioned, one or multiple technologies such as
>>>                     admission control/advanced or basic QoS/capacity
>>>                     planning/resource reservation either on the edge
>>>                     nodes or the transit nodes would be needed, and
>>>                     the mechanisms can have specific applicability
>>>                     to different network applications.
>>>                     Best regards,
>>>                     Jie
>>>                     *From:*Krzysztof Szarkowicz
>>>                     [mailto:kszarkowicz@gmail.com
>>>                     <mailto:kszarkowicz@gmail.com>]
>>>                     *Sent:*Thursday, April 14, 2022 9:00 PM
>>>                     *To:*Dongjie (Jimmy) <jie.dong@huawei.com
>>>                     <mailto:jie.dong@huawei.com>>
>>>                     *Cc:*John E Drake <jdrake@juniper.net
>>>                     <mailto:jdrake@juniper.net>>;adrian@olddog.co.uk
>>>                     <mailto:adrian@olddog.co.uk>;
>>>                     <mohamed.boucadair@orange.com
>>>                     <mailto:mohamed.boucadair@orange.com>>
>>>                     <mohamed.boucadair@orange.com
>>>                     <mailto:mohamed.boucadair@orange.com>>;teas@ietf.org
>>>                     <mailto:teas@ietf.org>
>>>                     *Subject:*Re: [Teas] [E] Re: Slicing Framework
>>>                     Open issue #1 : Service != Realization
>>>                     Hi Jie,
>>>                     I agree, NRP is a realization, and a such, my
>>>                     initial comments (few weeks ago) was that it
>>>                     should not be mentioned at all in the framework
>>>                     document, but should be left to the documents
>>>                     describing the realization.
>>>                     If, however, NRP is mandated by the framework
>>>                     document for realization, the wording for NRP in
>>>                     the framework document should be wide enough, to
>>>                     allow different realization options (described
>>>                     in different realization documents). For
>>>                     example, realization option mentioned by Med:
>>>                     * admission control with advanced QoS (large
>>>                     number of edge QoS classes) at the transport edge
>>>                     * basic QoS (limited number of transport core
>>>                     QoS classes) in transport core
>>>                     * mapping between large number of transport edge
>>>                     QoS classes to limited number transport core QoS
>>>                     classes
>>>                     * capacity planning
>>>                     has no good match with current wording about NRP
>>>                     in the framework document, IMHO.
>>>                     Please see as well inline.
>>>                     Thanks,
>>>                     Krzysztof
>>>
>>>                         On 2022 -Apr-14, at 09:05, Dongjie (Jimmy)
>>>                         <jie.dong@huawei.com
>>>                         <mailto:jie.dong@huawei.com>> wrote:
>>>                         Hi John,
>>>                         Thanks for the discussion on this point.
>>>                         Please see further inline with [Jie]:
>>>                         *From:*John E Drake
>>>                         [mailto:jdrake@juniper.net
>>>                         <mailto:jdrake@juniper.net>]
>>>                         *Sent:*Wednesday, April 13, 2022 9:44 PM
>>>                         *To:*Dongjie (Jimmy) <jie.dong@huawei.com
>>>                         <mailto:jie.dong@huawei.com>>; Krzysztof
>>>                         Szarkowicz <kszarkowicz@gmail.com
>>>                         <mailto:kszarkowicz@gmail.com>>;adrian@olddog.co.uk
>>>                         <mailto:adrian@olddog.co.uk>;
>>>                         <mohamed.boucadair@orange.com
>>>                         <mailto:mohamed.boucadair@orange.com>>
>>>                         <mohamed.boucadair@orange.com
>>>                         <mailto:mohamed.boucadair@orange.com>>
>>>                         *Cc:*teas@ietf.org <mailto:teas@ietf.org>
>>>                         *Subject:*RE: [Teas] [E] Re: Slicing
>>>                         Framework Open issue #1 : Service != Realization
>>>                         Hi,
>>>                         Upon re-reading Krzysztof’s email, I think
>>>                         we should keep the existing text and
>>>                         supplement it with Krzysztof’s text, but
>>>                         striking the second sentence. Comments
>>>                         inline below.
>>>                         Yours Irrespectively,
>>>                         John
>>>                         Juniper Business Use Only
>>>                         *From:*Dongjie (Jimmy) <jie.dong@huawei.com
>>>                         <mailto:jie.dong@huawei.com>>
>>>                         *Sent:*Wednesday, April 13, 2022 2:53 AM
>>>                         *To:*Krzysztof Szarkowicz
>>>                         <kszarkowicz@gmail.com
>>>                         <mailto:kszarkowicz@gmail.com>>;adrian@olddog.co.uk
>>>                         <mailto:adrian@olddog.co.uk>; John E Drake
>>>                         <jdrake@juniper.net
>>>                         <mailto:jdrake@juniper.net>>;
>>>                         <mohamed.boucadair@orange.com
>>>                         <mailto:mohamed.boucadair@orange.com>>
>>>                         <mohamed.boucadair@orange.com
>>>                         <mailto:mohamed.boucadair@orange.com>>
>>>                         *Cc:*teas@ietf.org <mailto:teas@ietf.org>
>>>                         *Subject:*RE: [Teas] [E] Re: Slicing
>>>                         Framework Open issue #1 : Service != Realization
>>>                         *[External Email. Be cautious of content]*
>>>                         Hi Krzysztof,
>>>                         One concern is the text you proposed is the
>>>                         level of detail which the framework document
>>>                         was trying to avoid.
>>>                         And as for the examples you provided, I’m
>>>                         not sure if all of them can be called NRP.
>>>                         For example:
>>>                         a)collection of paths optimized based on
>>>                         certain criteria. For example low latency
>>>                         paths for NSP-A, and high capacity paths for
>>>                         NSP-B.
>>>                         Low latency paths and high capacity paths
>>>                         may be obtained by using different metric
>>>                         types in Flex-Algo or other path
>>>                         computation, while as mentioned in a
>>>                         previous mail, depends on the network
>>>                         structure and topology, the path computed
>>>                         based on different metric types or
>>>                         constraints may still be the same or contain
>>>                         a set of shared links.
>>>                         *//*
>>>                         */[JD] What you are describing is how the
>>>                         NRP specified in a), above, might be
>>>                         instantiated. I think a) is consistent with
>>>                         the existing text /*
>>>                         *//*
>>>                         *[Jie] My point was that the mechanism in a)
>>>                         may not be a good example for NRP
>>>                         instantiation. As it is only path
>>>                         computation and does not describe how the
>>>                         resources are managed or reserved for
>>>                         different NRPs.*
>>>                         *//*
>>>                         Then it is not clear how the performance of
>>>                         services mapped to different NRPs with
>>>                         shared paths or links can be guaranteed. IMO
>>>                         some kind of resource reservation or
>>>                         management is needed for different NRPs.
>>>                         *//*
>>>                         */[JD] This is an issue for the service
>>>                         provider/*
>>>                         *[Jie] Indeed service provider needs the
>>>                         mechanisms which can create NRPs to meet the
>>>                         performance requirement of different
>>>                         services, even if the paths or links are
>>>                         shared with other services.*
>>>
>>>                     [Krzysztof] This is the question of realization,
>>>                     not the question of the framework. Some
>>>                     realization might use some advanced resource
>>>                     reservation/management for each link in the
>>>                     network, to squeeze out the link to last
>>>                     possible bit, some other realization might just
>>>                     use advanced reservation techniques on some
>>>                     links only (for example transport edge links),
>>>                     while using more loosely techniques on other
>>>                     links (e.g. transport core links). Some other
>>>                     realization might over provision certain links,
>>>                     instead of using advanced reservation mechanisms
>>>                     on these links. And, there could be dozens of
>>>                     different realization options, optimized for
>>>                     specific underlying technology. The framework
>>>                     document should not dictate any realization
>>>                     option, IMHO. It should be left to the
>>>                     realization documents.
>>>
>>>                         Best regards,
>>>                         Jie
>>>                         *From:*Teas [mailto:teas-bounces@ietf.org
>>>                         <mailto:teas-bounces@ietf.org>]*On Behalf
>>>                         Of*Krzysztof Szarkowicz
>>>                         *Sent:*Tuesday, April 12, 2022 10:08 PM
>>>                         *To:*adrian@olddog.co.uk
>>>                         <mailto:adrian@olddog.co.uk>; John E Drake
>>>                         <jdrake@juniper.net
>>>                         <mailto:jdrake@juniper.net>>;
>>>                         <mohamed.boucadair@orange.com
>>>                         <mailto:mohamed.boucadair@orange.com>>
>>>                         <mohamed.boucadair@orange.com
>>>                         <mailto:mohamed.boucadair@orange.com>>
>>>                         *Cc:*teas@ietf.org <mailto:teas@ietf.org>
>>>                         *Subject:*Re: [Teas] [E] Re: Slicing
>>>                         Framework Open issue #1 : Service != Realization
>>>                         John, Adrian, Med
>>>                         In that case, I would propose following text
>>>                         update. The reason is, from the current
>>>                         text, I cannot extract the the examples
>>>                         provided by Med and Adrian could be and well
>>>                         considered as an NSP realization.
>>>                         ===== Current Text ============
>>>                         An NRP is simply a collection of resources
>>>                         identified in the underlay network.  Thus,
>>>                         the NRP is a scoped view of a topology and
>>>                         may be considered as a topology in its own
>>>                         right.  The process of determining the NRP
>>>                         may be made easier if the underlay network
>>>                         topology is first filtered into a Filter
>>>                         Topology in order to be aware of the subset
>>>                         of network resources that are suitable for
>>>                         specific NRPs, but this is optional.
>>>                         ====== End of current text ==========
>>>                         ===== New Text ============
>>>                         It is out of scope for this document to
>>>                         describe the details, how an NSP can be
>>>                         realized. However, at a high-level, an NRP
>>>                         is simply a collection of resources
>>>                         identified in the underlay network. Some
>>>                         (none exhaustive) examples of an NSP
>>>                         realization are:
>>>                         a) collection of paths optimized based on
>>>                         certain criteria. For example low latency
>>>                         paths for NSP-A, and high capacity paths for
>>>                         NSP-B.
>>>                         b) admission control - possibly with large
>>>                         number of QoS classes - at the transport
>>>                         access, coupled with limited set of
>>>                         transport core QoS classes (PDBs), and N:M
>>>                         mapping between access and core classes.
>>>                         c) combination of above
>>>                         d) more complex realization schemes, with
>>>                         combinations of advanced QoS at both the
>>>                         access and transport core, possibly coupled
>>>                         with Filter Topology and different path
>>>                         optimizations methods.
>>>                         ====== End of new text ==========
>>>                         Best regards,
>>>                         Krzysztof Szarkowicz
>>>
>>>                             On 2022 -Apr-01, at 14:43, John E Drake
>>>                             <jdrake@juniper.net
>>>                             <mailto:jdrake@juniper.net>> wrote:
>>>                             Krzysztof,
>>>                             The usual answer to such a request is to
>>>                             ask you to provide text.
>>>                             Yours Irrespectively,
>>>                             John
>>>
>>>                             On 2022 -Apr-01, at
>>>                             15:44,mohamed.boucadair@orange.com
>>>                             <mailto:mohamed.boucadair@orange.com>wrote:
>>>                             Re-,
>>>                             Indeed.
>>>                             FWIW, some of this is captured in
>>>                             RFC7297 with a focus on legacy mechanisms:
>>>                             ==
>>>                             These requirements include: reachability
>>>                             scope (e.g., limited scope,
>>>                             Internet-wide), direction, bandwidth
>>>                             requirements, QoS parameters
>>>                             (e.g., one-way delay [RFC2679], loss
>>>                             [RFC2680], or one-way delay
>>>                             variation [RFC3393]), protection, and
>>>                             high-availability guidelines
>>>                             (e.g., restoration in less than 50 ms,
>>>                             100 ms, or 1 second).
>>>                             These requirements are then translated
>>>                             into IP/MPLS-related technical
>>>                             clauses (e.g., need for recovery means,
>>>                             definition of the class of
>>>                             service, need for control-plane
>>>                             protection, etc.).  In a later stage,
>>>                             these various clauses will be addressed
>>>                             by the activation of adequate
>>>                             network features and technology-specific
>>>                             actions (e.g., Multiprotocol
>>>                             Label Switching Traffic Engineering
>>>                             (MPLS-TE, [RFC3346]), Resource
>>>                             Reservation Protocol (RSVP, [RFC2205]),
>>>                             Open Shortest Path First
>>>                             (OSPF), Intermediate System to
>>>                             Intermediate System (IS-IS), etc.), by
>>>                             means of CPP-derived configuration
>>>                             information.
>>>                             …
>>>                             The CPP template aims to capture
>>>                             connectivity needs and to represent
>>>                             and value these requirements in a
>>>                             standardized manner. Service- and
>>>                             Customer-specific IP provisioning rules
>>>                             may lead to a dramatic
>>>                             increase of the number of IP transfer
>>>                             classes that need to be
>>>                             (pre-)engineered in the network. 
>>>                             Instantiating each CPP into a
>>>                             distinct class of service should
>>>                             therefore be avoided for the sake of
>>>                             performance and scalability.
>>>                             Therefore, application-agnostic IP
>>>                             provisioning practices should be
>>>                             recommended, since the requirements
>>>                             captured in the CPP can be used
>>>                             to identify which network class of
>>>                             service is to be used to meet
>>>                             those requirements/guarantees. From that
>>>                             standpoint, the CPP concept
>>>                             is meant to design a limited number of
>>>                             generic classes so that
>>>                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>>                             individual CPP documents, by capturing
>>>                             the connectivity requirements
>>>                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>>                             of services, applications, and
>>>                             Customers, can be easily mapped to
>>>                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>>                             these classes.
>>>                             ^^^^^^^^^^^^
>>>                             ==
>>>                             Cheers,
>>>                             Med
>>>                             *De :*Krzysztof Szarkowicz
>>>                             <kszarkowicz@gmail.com
>>>                             <mailto:kszarkowicz@gmail.com>>
>>>                             *Envoyé :*vendredi 1 avril 2022 15:26
>>>                             *À :*BOUCADAIR Mohamed INNOV/NET
>>>                             <mohamed.boucadair@orange.com
>>>                             <mailto:mohamed.boucadair@orange.com>>
>>>                             *Cc :*adrian@olddog.co.uk
>>>                             <mailto:adrian@olddog.co.uk>;teas@ietf.org
>>>                             <mailto:teas@ietf.org>
>>>                             *Objet :*Re: [Teas] [E] Re: Slicing
>>>                             Framework Open issue #1 : Service !=
>>>                             Realization
>>>                             Med,
>>>                             We are on the same page here. I see this
>>>                             as well as predominant approach, in fact.
>>>                             Cheers,
>>>                             Krzysztof
>>>
>>>                                 On 2022 -Apr-01, at 15:20,
>>>                                 <mohamed.boucadair@orange.com
>>>                                 <mailto:mohamed.boucadair@orange.com>>
>>>                                 <mohamed.boucadair@orange.com
>>>                                 <mailto:mohamed.boucadair@orange.com>>
>>>                                 wrote:
>>>                                 Krzysztof,
>>>                                 Admission control + use of limited
>>>                                 set of core QoS classes (PDBs) +
>>>                                 much more access QoS classes + map
>>>                                 access QoS classes to core classes +
>>>                                 no multi-topology/customized path
>>>                                 selection is also an example network
>>>                                 partitioning. I even expect this to
>>>                                 be the privileged approach when
>>>                                 legacy forwarding mechanisms should
>>>                                 be used to fulfil slicing objectives.
>>>                                 Cheers,
>>>                                 Med
>>>                                 *De :*Krzysztof Szarkowicz
>>>                                 <kszarkowicz@gmail.com
>>>                                 <mailto:kszarkowicz@gmail.com>>
>>>                                 *Envoyé :*vendredi 1 avril 2022 10:30
>>>                                 *À :*BOUCADAIR Mohamed INNOV/NET
>>>                                 <mohamed.boucadair@orange.com
>>>                                 <mailto:mohamed.boucadair@orange.com>>;adrian@olddog.co.uk
>>>                                 <mailto:adrian@olddog.co.uk>
>>>                                 *Cc :*teas@ietf.org
>>>                                 <mailto:teas@ietf.org>
>>>                                 *Objet :*Re: [Teas] [E] Re: Slicing
>>>                                 Framework Open issue #1 : Service !=
>>>                                 Realization
>>>                                 Adrian, Med,
>>>                                 Returning to this. I’ve seen many
>>>                                 design cases with SPs, where the
>>>                                 network is designed physically in
>>>                                 very structured manner. Also, I’ve
>>>                                 seen some analysis done by couple of
>>>                                 SPs, that as the result of this very
>>>                                 structured network design, after
>>>                                 making internal analysis, they don’t
>>>                                 really see the difference between
>>>                                 path placement done using IGP
>>>                                 metric, and path placement done
>>>                                 using delay metric. Hence, even
>>>                                 introducing some flex-algos (TE
>>>                                 meshes) with different metric
>>>                                 optimization is questionable here
>>>                                 (as the resulting paths are the same).
>>>                                 To realize services with SLO
>>>                                 commitments, these SPs today
>>>                                 extensively use admission control at
>>>                                 the edge (some times even relatively
>>>                                 complex admission control schemes at
>>>                                 the edge). But, they don’t use
>>>                                 anything specific (TE, Flex-Algo) in
>>>                                 the transport, apart from mentioned
>>>                                 admission control at the edge
>>>                                 (ingress/egress policers/shapers),
>>>                                 basic QoS on transit, network
>>>                                 capacity planning, and timely
>>>                                 capacity upgrades, where needed.
>>>                                 Does this approach could be
>>>                                 considered as well as some way of
>>>                                 ’network resource partitioning’
>>>                                 mentioned in the draft?
>>>                                 Cheers,
>>>                                 Krzysztof
>>>
>>>                                     On 2022 -Mar-28, at 12:26,
>>>                                     Krzysztof Szarkowicz
>>>                                     <kszarkowicz@gmail.com
>>>                                     <mailto:kszarkowicz@gmail.com>>
>>>                                     wrote:
>>>                                     OK,
>>>                                     If a realization example of
>>>                                     network partition is flex-algo +
>>>                                     admission control, then I am fine.
>>>                                     Thanks,
>>>                                     Krzysztof
>>>
>>>                             _________________________________________________________________________________________________________________________
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