topic Re: DEVASC200-901 OSG .. yang module question/mistake? in DevNet General Discussions

DEVASC200-901 OSG .. yang module question/mistake?

jlw7595 — Wed, 14 May 2025 02:05:32 GMT

I think te first highlight is wrong module name. The updated RFC calls the module ietf-inet-type.

For the second highlight, is this saying all of the ietf-inet-types are now merged into ietf-yang-types and they can all be referenced with the Yang prefix? How does the import know to import the network module also?

Thanks in advance!

Re: DEVASC200-901 OSG .. yang module question/mistake?

bigevilbeard — Wed, 14 May 2025 08:28:39 GMT

@jlw7595 Nice catch, I think you are right here and the module name is updated in more recent RFCs. The correct module name, as you pointed out and the OCG seems to be using an older version of the module name.

Side note - cos i am a super geek for this type of stuff and love to Google such fact

RFC 6991, which covers both ietf-yang-types and ietf-inet-types, was published in July 2013. This is before the book's publication date of 2020. It's possible the book refers to an earlier draft or has a minor inaccuracy.

The second question, from what i recall there is actually two separate IETF modules, the first is ietf-yang-types, this contains general data type and the second ietf-inet-types , which hs networking/internet specific data types. The import statement shown in the example is only importing the ietf-yang-types module amd it does not automatically import ietf-inet-types. The prefix statement, defines how to reference the imported types (using the "yang:" prefix).

Here are the links i used, to check this.

ietf-yang-types: RFC 6991 - Common YANG Data Types
ietf-inet-types: This is also covered in RFC 6991 - Common YANG Data Types

For the OCG book, you want to check the book corrections on Cisco Press to see if has been brought up.

Re: DEVASC200-901 OSG .. yang module question/mistake?

jlw7595 — Wed, 14 May 2025 16:02:40 GMT

Thanks @bigevilbeard I appreciate your response! So the next paragraph after the import "ietf-yang-types" is wrong too...? You cant use the prefix assigned to ietf-yang-types to call a data type from the ietf-inet-types module, right?

I typically keep track of errata as I study. It's a character flaw. I have a list of corrections that I was going to try to get in before the next rev. of OCG, but I saw the preorder open up on Amazon already, May be too late for that.

Re: DEVASC200-901 OSG .. yang module question/mistake?

bigevilbeard — Wed, 14 May 2025 17:04:02 GMT

@jlw7595 yes as far as iknow you cannot use the "yang:" prefix to access types from the ietf-inet-types module when you have only imported ietf-yang-types. They are distinct modules, and so each needs to be imported separately with its own prefix.

Perhaps the intention of this paragraph is to illustrate the general mechanism of using a prefix after an import, with ietf-yang-types as the initial example. I dont have this books to hand, and it been years since i read it, so it could be the next parts would introduce additional modules and clarify that each requires its own import and prefix.

Difficult to say is this is updated in the next version of the book to align with the v2, some books sections remain very much the same and only sections/chapter change per the exam blue print.

Hope this helps here.