Hi Adrian, 

The answers are much the same as for the OSPF flex-algo YANG (as were your 
comments). 

> On Mar 25, 2026, at 1:45 PM, Adrian Farrel via Datatracker <[email protected]> 
> wrote:
> 
> Document: draft-ietf-lsr-isis-flex-algo-yang
> Title: YANG Data Model for IS-IS Application-Specific Link Attributes and
> Flexible Algorithm Reviewer: Adrian Farrel Review result: Has Issues
> 
> Hi,
> 
> I have been selected as the Operational Directorate (opsdir) reviewer for this
> Internet-Draft.
> 
> The Operational Directorate reviews all operational and management-related
> Internet-Drafts to ensure alignment with operational best practices and that
> adequate operational considerations are covered.
> 
> A complete set of "Guidelines for Considering Operations and Management in 
> IETF
> Specifications" can be found at
> https://datatracker.ietf.org/doc/draft-opsarea-rfc5706bis/.
> 
> While these comments are primarily for the Operations and Management Area
> Directors (Ops ADs), the authors should consider them alongside other feedback
> received.
> 
> Thank you for your work on this document. Please address these comments or 
> feel
> free to contact me for clarification and/or discussion.
> 
> Best regards,
> 
> Adrian
> 
> ======
> 
> Document: draft-ietf-lsr-isis-flex-algo-yang-05
> 
> Reviewer: Adrian Farrel ([email protected])
> 
> Review Date: 2026-03-25
> 
> Intended Status: Standards Track
> 
> Summary
> 
> This document defines YANG models for handling flex-algo and
> application-specific link attributes in IS-IS. As such, it depends heavily on
> the protocol work in RFC 9350 and RFC 9479. The document contains two
> IANA-managed YANG modules, one new module, and one that augments the YANG 
> model
> defined in RFC 9130.
> 
> This document is a pair with draft-ietf-lsr-opspf-flex-algo-yang and depends 
> on
> the two IANA-managed YANG modules defined there. It is a little disconcerting
> that there is not an easy mapping between the two protocol models because of
> different foundational protocol work.
> 
> The document shepherd write-up is deficient. In answer to question 4 (For
> protocol documents, are there existing implementations of the contents of the
> document? ) it says "N/A". But this is a Standards Track protocol document.
> YANG models are implementable and it would give significant credence to the
> completeness of this specification if this question had been answered with
> implementation details. (Of course, it would have been even better to see an
> Implementation Status section in the document.)
> 
> It remains up to the WG and AD whether to pursue publication of an
> unimplemented YANG model.

Same response as OSPF. The LSR WG doesn't require implementation. 


> 
> The comments that follow are very similar to those for the OSPF document. This
> may be because the source text was block copied.
> 
> == Management Considerations ==
> 
> Failure cases are covered by a single Notification for flex-algo not 
> supported.
> There is no equivalent for metric not supported, although that is a less
> critical issue. There are no controls available to turn the reporting on or
> off, and to throttle reporting.
> 
> == Major Issues ==
> 
> iana-igp-metric-types in the OSPF document has
> 
>     identity bandwidth-metric {
>       base metric-type;
>       description
>         "Bandwidth metric.";
>       reference
>         "draft-ietf-lsr-flex-algo-bw-con";
>     }
> 
> There is a set of codepoints for "user-defined metrics" and "flexible
> algorithms". I see leaf algo-number, but nothing equivalent for metrics.

These are ranges not explicit values. 


> 
> But I also don't understand how algo-number, metric-type, and calc-type are
> used. Surely algo-number and calc-type are complementary with only one of them
> having meaning at once? Don't you need a Bool to say whether to use 
> algo-number
> or calc-type? (and similarly for metric-type or the new user-defined-metric
> type)
> 
> Further, shouldn't algo-number have a range clause?

Only for configuration. I'll update the read-only nodes to include the range in 
the
description. 


> 
> Further, the description for calc-type is surely wrong. algo-type is a base
> identity not an integer.
> 
> Lastly, in flex-algo-not-supported, the leaf algo-number is a uint8 which
> clashes with the use of the identity.
> 
> ---
> 
> When I see a Notification defined, I expect to see some way to turn on and off
> the generation of notifications, and ideally a way to control the rate of
> generation.

This comment is best addressed with a general solution. We don't want this done 
for
every YANG notification uniquely. Please address this specification gap with the
NETMOD WG. 


> 
> ---
> 
> What happens if more flags are added to the SABM registry? Shouldn't you be
> using an IANA-managed registry for that, too?

Same response as OSPF. Then the draft that defines the bit will create the new
registry. 


> 
> == Minor Issues ==
> 
> While the tree diagrams are useful, it is a shame that there is no text
> describing the two OSPF models and how they are used.

I guess you copied the comments from your OSPF review. There are descriptions of
models. 


> 
> ---
> 
> You have a number of imports from other modules. While your reference clauses
> are clear with their pointers to the relevant RFCs, those RFCs don't appear in
> the References section. What you need to do is either provide a table of
> imports (as is often done - for example, section 1.3 of RFC 9731), or some 
> text
> above each module saying "This module imports from RFCwxyz". Then you can add
> the documents to the References section. I think they are all Normative
> references.
> 
> I see, at least:
> RFC 6991
> RFC 8349
> RFC 8919
> RFC 8776

Will add these. 


> 
> ---
> 
> Why does this model use a unint 16 for the interface-asla and not the 
> sabm-bits
> identity?

Will fix.

> 
> == Nits ==
> 
> All of the copyright statements appear to be ood for document posted this 
> year.]

Will fix. 


> 
> ---
> 
> 2.
> 
>   This document defined a YANG module for IS-IS Application-Specific
>   Link Attributes as defined in [RFC9479].
> 
> s/defined/defines/

Will fix. 

> ---
> 
>       container sabm {
>         leaf-list sabm-bits {
>           type identityref {
>             base sabm-bit;
>           }
>           description
>             "SABM bits list. This list will contain
>              identities for the bits which are set in the
>              SABA bits.";
>         }
>         description
>           "Standard Application Identifier Bit Mask.";
>       }
> 
> s/SABA/SABM/  ??

Yes - will fix. 
> 
> ---
> 
>       container isis-asla {
>         list interface-asla {
>           key "app-id";
>           leaf app-id {
>             type uint16 {
>               range "0 .. 1023";
>             }
>             description
>               "Application ID.
>                0 - RSVP TE. 1 - Segment Routing Policy.
>                2 - Loop-Free Alternate.";
>           }
> 
> Would be nice to list the IDs on separate lines.

Sure. The leaf type is changed as per your previous comment.

Thanks,
Acee


> 
> 
> 

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