Re: [Teas-ns-dt] Appendix text on isolation

[Xufeng Liu <[e-mail]>]

Hi Kiran,

Jary's proposal describes the "isolation" as two parts:

<quote>
The term “isolation” implies in part traffic separation (a common feature
in VPNs) and in part the selection of dedicated resources. Dedicated
resources can help assure that, for instance, traffic in other slices does
not affect a given slice.
</quote>
Your text has added another part: "interference avoidance".

However, I am not sure "interference avoidance" can be classified as the
3rd part. It is rather a fundamental characteristic achieved by both parts
above. Therefore, I'd prefer the previous two-parts description in this
context. If "interference avoidance" is described, the topic could be a
separate section.

Since this is a definition document, should we provide clearly defined
terms for these two parts of the "isolation": "traffic isolation" and
"resource isolation", so that we would have a terminology reference for
later accurate usage.

Thanks,
- Xufeng

On Mon, Jun 22, 2020 at 9:48 PM Dongjie (Jimmy) <[e-mail]> wrote:

> Hi Kiran,
>
>
>
> Thanks for incorporate the comments together into the text. It looks good
> to me.
>
>
>
> I agree that the statement in last paragraph applies to all the
> characteristics of a transport slice, thus it is better to remove it from
> this section. Thanks.
>
>
>
> Best regards,
>
> Jie
>
>
>
> *From:* Kiran Makhijani [mailto:[e-mail]]
> *Sent:* Tuesday, June 23, 2020 4:47 AM
> *To:* LUIS MIGUEL CONTRERAS MURILLO <
> [e-mail]>gt;; [e-mail]
> *Cc:* Dongjie (Jimmy) <[e-mail]>om>; Jari Arkko <jari..arkko=
> [e-mail]>
> *Subject:* Re: Appendix text on isolation
>
>
>
> Ack. I was tentative too.
>
>
>
> Regards
>
> Kiran
>
>
> ------------------------------
>
> *From:* LUIS MIGUEL CONTRERAS MURILLO <
> [e-mail]>
> *Sent:* Monday, June 22, 2020 1:44:49 PM
> *To:* Kiran Makhijani <[e-mail]>om>; [e-mail] <
> [e-mail]>
> *Cc:* Dongjie (Jimmy) <[e-mail]>om>; Jari Arkko <
> jari.arkko=[e-mail]>
> *Subject:* RE: Appendix text on isolation
>
>
>
> Hi Kiran,
>
>
>
> Thanks for taking care of this. Let me insist in a small but important
> part. It is respect to the last paragraph, where it is mentioned that any
> mechanisms can provide 100% of guarantee. My point is that being true, this
> is applicable not only for the isolation concept but for any other
> consideration, e.g. meeting whatever SLO such as bandwidth. Then, in my
> view, leaving that reference in this annex could make apparent that such
> statement is only related to isolation when in reality it is related to
> whatever characteristic of the transport slice.
>
>
>
> So I would suggest to remove it.
>
>
>
> Best regards
>
>
>
> Luis
>
>
>
> *De:* Teas-ns-dt <[e-mail]> *En nombre de *Kiran
> Makhijani
> *Enviado el:* lunes, 22 de junio de 2020 22:00
> *Para:* [e-mail]
> *CC:* Dongjie (Jimmy) <[e-mail]>om>; Jari Arkko <
> jari.arkko=[e-mail]>
> *Asunto:* Re: [Teas-ns-dt] Appendix text on isolation
>
>
>
> Hi Jie, and all,
>
> Please review the final text, considering all the comments received so far.
>
>
>
> --begin--
>
> A.1.  On isolation requirements in a transport slice
>
>
>
>    Transport slices are perceived as if slice was provisioned for the
>
>    customer as a dedicated network with specific SLOs.  These committed
>
>    SLOs for a given customer should be maintained during the life-time
>
>    of the slice even in the face of potential disruptions.  Such
>
>    disruptions include sudden traffic volume changes either from the
>
>    customer itself or others, equipment failures in the service provider
>
>    network, and various misbehaviors or attacks.
>
>
>
>    The service provider needs to ensure that their network can provide
>
>    the requested slices with the availability agreed with its customers.
>
>    Some of the main technical approaches to ensuring guarantees are
>
>    about network planning, managing capacity, prioritizing, policing or
>
>    shaping customer traffic, selecting dedicated resources, and so on.
>
>
>
>    One term that has commonly been used in this context is "isolation"
>
>    and is also discussed in the [I-D.ietf-teas-enhanced-vpn].
>
>
>
>    A customer of transport slice may ask for traffic separation,
>
>    selection of dedicated resources, or interference avoidance from
>
>    other traffic.  The term "isolation" can refer to any or all of them.
>
>    For instance, dedicated resources can help assure that traffic in
>
>    other slices does not affect a given slice.  Simillarly, traffic
>
>    separation can be provided by VPN technologies, and interference
>
>    avoidance may be provided by mechanisms such as technical approaches
>
>    mentioned in previous paragraph.  Moreover, these are some of the
>
>    examples of particular realization of requirement for guarantees;
>
>    other mechanisms may also be used.
>
>
>
>    It should also be noted that neither above mentioned nor the other
>
>    mechanisms can provide a 100% guarantee against outage problems.  To
>
>    maintain protection against resource and equipment failures
>
>    techniques such as redundancy are also needed.
>
> --end--
>
> Thanks
>
> Kiran
>
>
>
> *From:* Dongjie (Jimmy) <jie.dong@huawei..com <[e-mail]>>
> *Sent:* Wednesday, June 17, 2020 3:17 AM
> *To:* Kiran Makhijani <[e-mail]>om>; Jari Arkko <
> jari.arkko=[e-mail]>gt;; [e-mail]
> *Subject:* RE: Appendix text on isolation
>
>
>
> Hi Kiran,
>
>
>
> I understand your point, while since isolation is specified as a
> requirement of network slicing in other SDOs (e.g. GSMA, 3GPP), some
> customers may also ask for isolation in end-to-end network slice or
> transport slice. My opinion is it may be helpful to interpret and clarify
> isolation as more specific requirements in IETF and transport slice context
> (such as traffic separation, interference avoidance, etc.)
>
>
>
> Another option is to describe the specific requirement and the
> corresponding realization directly: “A consumer of transport slice may ask
> for traffic separation or interference avoidance from other transport
> slices. The term “isolation” implies traffic separation, or interference
> avoidance, or both. Accordingly, from realization’s perspective, …”
>
>
>
> Best regards,
>
> Jie
>
>
>
>
>
> *From:* Kiran Makhijani [mailto:[e-mail]
> <[e-mail]>]
> *Sent:* Wednesday, June 17, 2020 11:05 AM
> *To:* Dongjie (Jimmy) <[e-mail]>om>; Jari Arkko <
> jari.arkko=[e-mail]>gt;; [e-mail]
> *Subject:* Re: Appendix text on isolation
>
>
>
> I am trying to say that customer should not have to ask for isolation but
> some abstraction of it. It may explicitly  ask for specific requirements
> but not isolation.
>
>
>
> It’s ok to go with your suggestion if its just me. Some text is repeated
> from 2nd para. So that still needs some work.
>
>
>
> Regards,
>
> Kiran
> ------------------------------
>
> *From:* Dongjie (Jimmy) <[e-mail]>
> *Sent:* Tuesday, June 16, 2020 7:26:03 PM
> *To:* Kiran Makhijani <[e-mail]>om>; Jari Arkko <
> jari.arkko=[e-mail]>gt;; [e-mail] <
> [e-mail]>
> *Subject:* RE: Appendix text on isolation
>
>
>
> Hi Kiran and all,
>
>
>
> Your concern is part of the reason that I suggest to describe the
> requirement and realization of isolation separately. Firstly,
> multi-dimension can help to clarify the different requirements related to
> isolation, such as traffic separation and interference avoidance, in my
> understanding both of which can be raised by a customer as requirement, and
> they do not reflect implementation details. Then the
> implementation-specific mechanisms could be briefly described to match each
> dimension of the requirement.
>
>
>
> The sentence you added in the end of the paragraph looks good, while maybe
> it could be better if such requirement description be moved to the
> beginning of the paragraph. Please check the modified text below:
>
>
>
> A consumer of transport slice may ask for isolation from other transport
> slices.
>
> The term “isolation” can refer to multiple dimensions of requirements,
>
> such as traffic separation, or interference avoidance, or both.
> Accordingly, from
>
> realization’s perspective, traffic separation can be provided by VPN
> technologies,
>
> and interference avoidance may be provided by mechanisms such as capacity
>
> planning, policing or shaping, priority mechanisms, selecting dedicated
> resources, and so on.
>
>
>
> Please let me know your thoughts. Thanks.
>
>
>
> Best regards,
>
> Jie
>
>
>
> *From:* Kiran Makhijani [mailto:[e-mail]
> <[e-mail]>]
> *Sent:* Wednesday, June 17, 2020 9:30 AM
> *To:* Dongjie (Jimmy) <[e-mail]>om>; Jari Arkko <
> jari.arkko=[e-mail]>gt;; [e-mail]
> *Subject:* RE: Appendix text on isolation
>
>
>
> Hi Jie, and all,
>
> One argument against using isolation as an SLO is that it is an
> implementation specific detail that customer should not have to (always)
> concern with. So I am not comfortable with the use of ‘multi-dimensional’.
>
> One way to separate realization and customer requirement may be we can use
> business objective/case. May be we can add, one sentence  at the end of the
> original paragraph. What do you think?
>
>
>
> The term “isolation” implies in part traffic separation (a common
>
> feature in VPNs) and in part the selection of dedicated
>
> resources. Dedicated resources can help assure that, for instance,
>
> traffic in other slices does not affect a given slice. However, it
>
> should also be noted that this is one particular realization of a
>
> requirement for guarantees, and other mechanisms may also be used,
>
> such as priority mechanisms or policing amount of traffic entering a
>
> link from different sources. Business objectives may require a customer
>
> to ask for explicit traffic separation or interference avoidance
> mechanisms.
>
>
>
> -Kiran
>
>
>
> *From:* Dongjie (Jimmy) <[e-mail]>
> *Sent:* Tuesday, June 16, 2020 3:15 AM
> *To:* Jari Arkko <jari.arkko=[e-mail]>rg>;
> [e-mail]
> *Cc:* Kiran Makhijani <[e-mail]>
> *Subject:* RE: Appendix text on isolation
>
>
>
> Hi Jari,
>
>
>
> Thanks for considering most of my comments in this revision.
>
>
>
> And as mentioned yesterday and in my previous email, I’d like to suggest
> whether the description about isolation could be rephrased a bit, so as to
> better clarify the requirement and realization of isolation in different
> dimensions.
>
>
>
> The term “isolation” can refer to multiple dimensions of requirements. A
> customer may ask for traffic separation or interference avoidance, or both.
> Accordingly, from realization’s perspective, traffic separation can be
> provided by VPNs, and interference avoidance can be provided by mechanisms
> such as capacity planning, priority mechanisms, policing or shaping,
> selecting dedicated resources, and so on.
>
>
>
> Hope this helps.
>
>
>
> Best regards,
>
> Jie
>
>
>
> *From:* Teas-ns-dt [mailto:[e-mail]
> <[e-mail]>] *On Behalf Of *Jari Arkko
> *Sent:* Tuesday, June 16, 2020 4:26 PM
> *To:* [e-mail]
> *Cc:* Kiran Makhijani <[e-mail]>
> *Subject:* Re: [Teas-ns-dt] Appendix text on isolation
>
>
>
> Here’s a suggested 2nd revision of the suggested text, based on
> yesterday’s comments on the call and Kiran’s email.
>
>
>
>
>
> Transport slices are perceived as if slice was provisioned for the
>
> customer as a dedicated network with specific SLOs. These committed
>
> SLOs for a given customer should be maintained during the life-time of
>
> the slice even in the face of potential disruptions.  Such disruptions
>
> include sudden traffic volume changes either from the customer itself
>
> or others, equipment failures in the service provider network, and
>
> various misbehaviors or attacks.
>
>
>
> The service provider needs to ensure that their network can provide
>
> the requested slices with the availability agreed with its
>
> customers. Some of the main technical approaches to
>
> ensuring guarantees are about network planning, managing capacity,
>
> priority mechanisms, policing or shaping customer traffic, selecting
>
> dedicated resources, and so on.
>
>
>
> One term that has commonly been also used in this context is
>
> "isolation". This is discussed further in the framework draft
>
> [I-D.nsdt-teas-ns-framework] and has also been a topic in
>
> [I-D.ietf-teas-enhanced-vpn].
>
>
>
> The term “isolation” implies in part traffic separation (a common
>
> feature in VPNs) and in part the selection of dedicated
>
> resources. Dedicated resources can help assure that, for instance,
>
> traffic in other slices does not affect a given slice. However, it
>
> should also be noted that this is one particular realization of a
>
> requirement for guarantees, and other mechanisms may also be used,
>
> such as priority mechanisms or policing amount of traffic entering a
>
> link from different sources.
>
>
>
> It should also be noted that neither dedicated resources or the other
>
> mechanisms can provide a 100% guarantee against problems.  To maintain
>
> protection against resource and equipment failures techniques such as
>
> redundancy are needed.
>
>
> ------------------------------
>
>
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