Subject: [Lsr] Mirja Kühlewind's No Objection on draft-ietf-ospf-yang-26: (with COMMENT)

From: Mirja Kühlewind via Datatracker <[email-masked]>
Date: Mon, 19 Aug 2019 09:25:30 -0700

Mirja Kühlewind has entered the following ballot position for
draft-ietf-ospf-yang-26: No Objection

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COMMENT:
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Just two quick questions about references:

- Is there no reference for mtu-ignore (see section 2.4)? If not, can you
further describe what exactly would be disabled?

- Also is there no reference for OSPF Non-Stop Routing (NSR) (see section
2.4)...?

And one more comment:

In the interface-common-config part (p76 and p77) you provide example or
default values for various intervals and delays. Where does those values come
from? Would it be possible to provide a reference/RFC that specifies actual
default values? Especially when you specify something normatively ("The value
MUST be greater than 'hello-interval'.") it would be good to provide a
reference!  Do any specification maybe also specify min and max value? If so,
you should mention them here as well! If not would it make sense to recommend
min and max values? If possible I would strongly support to describe min and
max values as well!

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From: "Acee Lindem (acee)" <[email-masked]>
Date: Tue, 20 Aug 2019 15:05:14 +0000

Hi Mirja, 

On 8/19/19, 12:25 PM, "Mirja Kühlewind via Datatracker" <[email-masked]> wrote:

    

I added "specified in section 10.6 of [RFC2328]." to the sentence. 

While many vendors have implemented this feature, there is no standard as the goal is to restart without other OSPF routers being impacted. We did add the additional text to describe the feature and differences with OSPF Graceful Restart. 
    
    And one more comment:

The whole question of defaults generated quite a lot of discussion as there isn't really any one-size-fits all default and the sample values are very conservative. This is how we ended up with sample values in the text rather than YANG defaults. Since the protocol specification doesn’t specify min and max values, we were hesitant to specify them in the YANG model more than 20 years later. Also, many vendors have supported sub-second hellos. This wasn't a good idea and it has been supplanted by BFD. I will add RFC 2328 Appendix C as a reference for the sample values. 

Thanks,
Acee

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From: Mirja Kuehlewind <[email-masked]>
Date: Tue, 20 Aug 2019 17:51:53 +0200

Hi Acee,

Thanks for these changes/additions.

One comment below.

> On 20. Aug 2019, at 17:05, Acee Lindem (acee) <[email-masked]> wrote:
> 
> Hi Mirja, 
> 

Good to hear that this was discussed! I understand the problem and a YANG is not the right place to “change” the spec. Adding a reference would be good!

One more question regarding the sentence with normative language above: Is that already specified in some other spec and it would make sense to not use normative language here but provide the reference? 

Mirja

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From: "Acee Lindem (acee)" <[email-masked]>
Date: Tue, 20 Aug 2019 17:26:35 +0000

Hi Mirja,

On 8/20/19, 11:52 AM, "Mirja Kuehlewind" <[email-masked]> wrote:

    Hi Acee,

    One comment below.

    
    One more question regarding the sentence with normative language above: Is that already specified in some other spec and it would make sense to not use normative language here but provide the reference?
In this case, the YANG model enforces the constraint. However, it is not stated explicitly in RFC 2328 so I'll make it a lower case "must". 

Thanks,
Acee
    
    Mirja