Re: [Teas] Example of model and modules designed for augmentation

Italo Busi <> Mon, 25 July 2022 19:40 UTC

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From: Italo Busi <>
To: Dhruv Dhody <>, Lou Berger <>
CC: "Rokui, Reza (Nokia - CA/Ottawa)" <>, TEAS WG <>
Thread-Topic: [Teas] Example of model and modules designed for augmentation
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Date: Mon, 25 Jul 2022 19:40:50 +0000
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Subject: Re: [Teas] Example of model and modules designed for augmentation
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Hi Dhruv,

What is the design objective of being able to “allow new attributes to added without updating YANG model”?

IMHO, updating a YANG model (either with a new revision or with an augmentation) is the best way to add attributes in an interoperable way since this allows the server to inform the client that new attributes have been added and the client to know which servers support or do not support the new attributes

Moreover, updating a YANG model provides a YANG formal definition for the new attributes such as the name, type, range (when applicable), measurement unit (when applicable), …

My 2 cents


From: Dhruv Dhody <>
Sent: lunedì 25 luglio 2022 18:36
To: Lou Berger <>
Cc: Rokui, Reza (Nokia - CA/Ottawa) <>; TEAS WG <>
Subject: Re: [Teas] Example of model and modules designed for augmentation

Hi Lou,

There were 2 seperate questions on that slide, but with the "opaque" example, the usecase proposed to us was for a way to add "new" attributes via pure configuration in the current model itself without the need for any augmentation.

Issue: To maintain the technology agnostic nature of the YANG model we use
1. A pair of (identity, value (string)) to support many attributes;
• a common practice, for instance different metric-types use a common leaf metric-value of uint64 (RFC8776).
2. Support for “opaque” attributes that can be configured without an identity
• This allow new attributes to added without updating YANG model
Concern: Using a string instead of an explicit type in YANG there could be interoperability issues. The use of opaque attributes that are not defined in YANG adds to this issue.

We need inputs from the WG if that is a valid usecase and the correct approach.


On Mon, Jul 25, 2022 at 9:23 PM Lou Berger <<>> wrote:

In the session you asked for an example of a model (and modules) that
have been designed with technology specific augmentation in mind.  For
an example, take a look at --
search for augment...


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