Re: [Lsr] Rtgdir last call review of draft-ietf-lsr-isis-sr-vtn-mt-05

[Daniele Ceccarelli <[e-mail]>]

I'm fine with the replies.

Thanks!
Daniele

On Tue, Jan 23, 2024 at 8:12 PM Acee Lindem <[e-mail]> wrote:

> Hi Daniele,
>
> It seems that your comments have either been addressed or at least
> responded. Please reply if you wish further discussion.
>
> Thanks,
> Acee
>
> > On Dec 1, 2023, at 10:42 AM, Daniele Ceccarelli <[e-mail]>
> wrote:
> >
> > Hi Chongfeng,
> >
> > Thanks for addressing my comments.
> > I would just suggest to add some text to the draft to explain the
> comment below
> >
> >
> > [Chongfeng] This is discussed in the scalability considerations section
> of this draft. This mechanism is useful for network scenarios in which the
> required number of VTN/NRP is small, the advantage is no protocol extension
> is required (as reflected by the document type). For network scenarios
> where the number of required VTN/NRP is large, more scalable solution would
> be needed, which may result in further protocol extensions and enhancements.
> >
> >
> > BR
> > Daniele
> >
> > On Wed, Nov 29, 2023 at 1:00 AM Chongfeng Xie <[e-mail]>
> wrote:
> >
> > Hi Daniele,
> >
> > Thanks a lot for your careful review and comments. Please see my replies
> inline [Chongfeng]:
> >
> > -----Original Message-----
> > From: Daniele Ceccarelli via Datatracker [mailto:[e-mail]]
> > Sent: Friday, November 24, 2023 10:21 PM
> > To: [e-mail]
> > Cc: [e-mail]; [e-mail];
> [e-mail]
> > Subject: Rtgdir last call review of draft-ietf-lsr-isis-sr-vtn-mt-05
> >
> > Reviewer: Daniele Ceccarelli
> > Review result: Has Issues
> >
> > - General: The term and concept of Enhanced VPN is being discussed in
> TEAS as part of the WG last call. I suggest to follow that thread and align
> the draft with whatever output will be agreed.
> >
> > [Chongfeng] Yes the terminology in this draft will align with the
> decision on terminology in in TEAS
> > - General: i would suggest to change the title into "Applicability"
> rather than using. Per my understanding this document describes how to use
> existing mechanisms to achieve something new (the status is correctly
> informational)
> >
> > [Chongfeng] Agree, we can make this change in next revision.
> > - Abstract: "enhanced isolation". i checked if it was defined in the
> framework for Enhanced VPNs in TEAS, but i couldn't find a definition there
> nor in this draft. What does it mean?
> >
> > [Chongfeng] We will align this description with the enhanced VPN
> framework draft.
> >
> > - VTN: is this a new term to identify a set of existing items? E.g. an
> ACTN VN, NRP, a set of RSVP-TE tunnel, a topology built with flex
> algo...are they cases of VTN or the VTN is a different thing?
> >
> > [Chongfeng] According to the recent discussion in TEAS, it is agreed to
> replace the term VTN with NRP.
> >
> > - Intro: s/than that can be provided/than the ones that can be provided
> >
> > [Chongfeng] OK.
> >
> > - "Another possible approach is to create a set of point-to-point paths,
> each with a set of network resources reserved along the path, such paths
> are called Virtual Transport Path (VTP)". In what is this different from an
> ACTN VN member? See RFC 8453.
> >
> > [Chongfeng] VN member as defined in RFC 8453 refers to "edge-to-edge
> link" exposed in the management plane, which is formed as end-to-end
> tunnels in the underlying networks. The term VTP refers to point-to-point
> underlay paths with network resource reserved along the path. So VTPs can
> be considered as one specific type of underlay tunnel with resource
> reservation. As we will replace VTN with NRP, we will consider whether the
> term VTP is still needed or not.
> >
> > - Introduction: "In some network scenarios, the required number of VTNs
> could be small, and it is assumed that each VTN is associated with an
> independent topology and has a set of dedicated or shared network
> resources. This document describes a simplified mechanism to build SR based
> VTNs in those scenarios." I don't understand, is there the need for a
> specific mechanisms (different from existing ones) only for particular
> cases in which the number of VTNs is small (smaller than other scenarios)?
> >
> > [Chongfeng] This is discussed in the scalability considerations section
> of this draft. This mechanism is useful for network scenarios in which the
> required number of VTN/NRP is small, the advantage is no protocol extension
> is required (as reflected by the document type). For network scenarios
> where the number of required VTN/NRP is large, more scalable solution would
> be needed, which may result in further protocol extensions and enhancements.
> >
> >  Section 3.1 "The usage of other TE attributes in topology-specific TLVs
> is for further study." The draft is pretty simple and small, can't the
> usage of other TE attributes be described here as well?
> >
> > [Chongfeng] Yes the encoding of TE attributes in topology-specific TLVs
> is simple, while a more important thing is to find valid use case for them.
> The current VTN/NRP use case only makes use of the bandwidth attribute,
> other TE attributes are not in the scope. Thus this statement is considered
> OK for this document.
> >
> > Best regards
> > Chongfeng
> >
>
>