Re: [alto] Opsdir early review of draft-ietf-alto-oam-yang-06

Jensen Zhang <> Tue, 25 April 2023 13:01 UTC

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From: Jensen Zhang <>
Date: Tue, 25 Apr 2023 21:01:20 +0800
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To: Dan Romascanu <>
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Subject: Re: [alto] Opsdir early review of draft-ietf-alto-oam-yang-06
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Hi Dan,

Sorry for the delay. Many thanks for your review. Please see our response
inline below.

On Fri, Apr 21, 2023 at 4:00 PM Dan Romascanu via Datatracker <> wrote:

> Reviewer: Dan Romascanu
> Review result: Has Nits
> Ready with Nits
> This document defines YANG data models for Operations, Administration, and
> Maintenance (OAM) & Management of ALTO. The operator can use these data
> models
> to set up an ALTO server, create, update and remove ALTO information
> resources,
> manage the access control, configure server discovery, and collect
> statistical
> data.
> I like this document. It is clearly written and very well structured. I
> liked
> the description of requirements, the information model corresponding to the
> requirements, and the extension example modules in the Appendices. These
> are
> all very useful for operators who need to understand and use the YANG
> modules.
> Understanding and using this document requires a good knowledge of ALTO.
> My review is focused on the design and data modelling issues relevant for
> operations and manageability. I did not perform a YANG review, I assume
> that
> YANG Doctors review is performed separately.
> This document is Ready with a couple of editorial comments.
> Editorial & Nits:
> 1. There are many more acronyms not included in Section 3 or expanded at
> first
> occurrence. Maybe the respective acronyms sections in the ALTO documents
> should
> be mentioned / referred

Thanks for pointing out this issue. We have included all the acronyms that
occur in the document in Sec 3. You can check the changes in our early edit


But we are not sure if the acronyms that only occur in the YANG modules
should also be included.

> 2. In Section
> > In practice, multiple ALTO servers can be deployed for scalability.
>    That may require communication among different ALTO servers.
>    The "ietf-alto" module does not contain any configuration for the
>    communication between peer ALTO servers.  Instead, it provides the
>    configuration for how an ALTO server can be discovered by another
>    ALTO server on demand (Figure 6).
> I understand that the communication between ALTO servers is out of scope.
> However, I do not understand how is the scalability requirement met. Is
> there /
> Will there be another YANG module to define this data model? Something else
> than YANG? Maybe this is described in another ALTO document that I did not
> find.

The scalability requirement is not explicitly defined in this document. It
looks like a part of R1 but is not mandatory.

And I am not quite sure what is the scalability requirement that you
mentioned here. There can be two kinds of scalability issues:

1. The scalability of a large number of network domains and elements. This
issue requires the deployment of multiple ALTO server instances in
different domains and communications among different ALTO servers in
different domains. WG is still discussing the related topic [2]. The
solution is not mature. So we consider it to be out of the scope of this


2. The scalability of a large number of client connections. i.e., the load
balance issue. This may need some autoscaling or load-balancing
configuration parameters. Is this what you want to add?