Re: [Teas] WG Last Call: draft-ietf-teas-actn-vn-yang-19

Hi Adrian, WG,

Thanks for your comments. They are very useful...

On Fri, Sep 29, 2023 at 2:03 AM Adrian Farrel <adrian@olddog.co.uk> wrote:

> Hi,
>
>
>
> I support this work and think that it is almost ready to move forward.
>
>
>
> Cheers,
>
> Adrian
>
>
>
> ===
>
>
>
> It is a bit odd that the filename mentions ACTN, and the document is
>
> quite strong on ACTN, but the Title and Abstract don't mention it at
>
> all, and the term doesn't show up until well into the Introduction.
>
>
>

Dhruv: I have added "This includes VN operations as per Abstraction and
Control of TE Networks (ACTN) framework." in the abstract. I have also
moved the ACTN sentence in the Introduction higher up.

> ---
>
>
>
> I would like the authors to add some more clarity early in the document
>
> about how the VN is represented in abstract terms to the customer. That
>
> is, it is presented as a connectivity matrix rather than as a network?
>
> I feel this is an important distinction in the field of virtual networks
>
> (consider the distinction between providing an L3VPN service and giving
>
> a customer access to a virtual subset of the underlay network resources
>
> that they can operate as if it was their own physical network). So, the
>
> distinction is about whether the virtual network is presented to the
>
> customer simply as edge connectivity or as a full network.
>
>
>

Dhruv: Following text is added:

   As per [RFC8795], a TE node connectivity matrix is the TE node's
   switching limitations in the form of valid switching combinations of
   the TE node's LTPs and potential TE paths.  The VN representation
   relies on a single abstract TE node with a connectivity matrix.  The
   VN can be abstracted as a set of edge-to-edge links (a Type 1 VN).
   Each link is the VN member that is mapped to the connectivity matrix
   entry (Section 2.1).  The VN can also be abstracted as a topology of
   virtual nodes and virtual links (a Type 2 VN).  Alongside the mapping
   of VN members to connectivity matrix entry, an underlay path can also
   be specified (Section 2.2).

Hope this clarifies it.

---
>
>
>
> There seems to be material in 2.1 and 2.2 repeated in 3.1 and 3.2. Is
>
> that necessary?
>
>
>

Dhruv: Removed.

> ---
>
>
>
> The description of the Type 1 VN in Sections 2.1 and 3.1 bothers me. It
>
> is true that you can represent this model as an abstract, but in general
>
> it is not wise. Well, unless you talk about "limited cross-connect
>
> capabilities."
>
>
>
> The example in this section presents a VN with 6 customer end-points and
>
> 4 abstract links (VN members). But, of course, when you represent this
>
> as an abstract node, there are 15 possible cross-connects and no way of
>
> knowing which ones don't apply.
>
>
>
> So I would strongly advise you stick with the "VN members"
>
> representation of abstract links, and not venture into the abstract node
>
> way of modeling it.
>
>
>
>
>

Dhruv: The abstract node is key to the YANG model for both VN type 1 and 2.
The connectivity matrix is how you limit the possibilities. I have added
dotted lines to show the VN-members in the figure 2 instead.

> ===
>
>
>
> There are a few trivial nits you could clean up at the same time.
>
>
>

Dhruv: These are fixed.

I have posted an update -

Name:     draft-ietf-teas-actn-vn-yang
> Revision: 20
> Title:    A YANG Data Model for Virtual Network (VN) Operations
> Date:     2023-10-14
> Group:    teas
> Pages:    50
> URL:
> https://www.ietf.org/archive/id/draft-ietf-teas-actn-vn-yang-20.txt
> Status:   https://datatracker.ietf.org/doc/draft-ietf-teas-actn-vn-yang/
> HTML:
> https://www.ietf.org/archive/id/draft-ietf-teas-actn-vn-yang-20.html
> HTMLized:
> https://datatracker.ietf.org/doc/html/draft-ietf-teas-actn-vn-yang
> Diff:
> https://author-tools.ietf.org/iddiff?url2=draft-ietf-teas-actn-vn-yang-20

I also wanted to formally note my support for publication as a co-author.

Thanks!
Dhruv

> 1.
>
>
>
>    such as Layer Three Virtual Private Network Service Model
>
>    (L3SM) [RFC8299], Layer Two Virtual Private Network Service Model
>
>    (L2SM) [RFC8466] and Layer One Connectivity Service Model (L1CSM)
>
>    [I-D.ietf-ccamp-l1csm-yang]
>
>
>
> Insert definite articles ("the") before each "Layer".
>
>
>
> ---
>
>
>
> 1.
>
>
>
>    The actual VN instantiation and computation is performed with
>
>    Connectivity Matrices sub-module of TE-Topology Model [RFC8795] which
>
>    provides TE network topology abstraction and management operation.
>
>    Once TE-topology Model is used in triggering VN instantiation over
>
>    the networks, TE-tunnel [I-D.ietf-teas-yang-te] Model will inevitably
>
>    interact with TE-Topology model for setting up actual tunnels and
>
>    LSPs under the tunnels.
>
>
>
> Insert definite article before each "TE-".
>
>
>
> ---
>
>
>
> 1.
>
>
>
>    The YANG model on the CMI is also known as customer service model in
>
>    [RFC8309].
>
>
>
> s/as/as the/
>
>
>
> ---
>
>
>
> 1.2.  Tree diagram
>
>
>
> s/diagram/Diagram/
>
>
>
> ---
>
>
>
> 2.
>
>
>
> The text should probably make reference to the figure.
>
>
>
> ---
>
>
>
> There is a line length problem near the bottom of page 41
>
>
>
> *From:* Teas <teas-bounces@ietf.org> *On Behalf Of *Vishnu Pavan Beeram
> *Sent:* 12 September 2023 13:19
> *To:* TEAS WG <teas@ietf.org>
> *Cc:* TEAS WG Chairs <teas-chairs@ietf.org>
> *Subject:* [Teas] WG Last Call: draft-ietf-teas-actn-vn-yang-19
>
>
>
> All,
>
> This starts a two-week working group last call on
>
> https://datatracker.ietf.org/doc/draft-ietf-teas-actn-vn-yang/
>
>
>
> The working group last call ends on September 26th, 2023.
>
> Please send your comments to the working group mailing list.
>
> Positive comments, e.g., "I've reviewed this document
> and believe it is ready for publication", are welcome!
> This is useful and important, even from authors.
>
> Note: IPR has been disclosed on this document
>
>
> Thank you,
> Pavan, Lou and Oscar
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