Re: Warren Kumari's Discuss on draft-ietf-bfd-yang-16: (with DISCUSS and COMMENT)

"Reshad Rahman (rrahman)" <rrahman@cisco.com> Wed, 04 July 2018 18:05 UTC

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From: "Reshad Rahman (rrahman)" <rrahman@cisco.com>
To: Warren Kumari <warren@kumari.net>
CC: The IESG <iesg@ietf.org>, "draft-ietf-bfd-yang@ietf.org" <draft-ietf-bfd-yang@ietf.org>, Jeffrey Haas <jhaas@pfrc.org>, "bfd-chairs@ietf.org" <bfd-chairs@ietf.org>, "rtg-bfd@ietf.org" <rtg-bfd@ietf.org>
Subject: Re: Warren Kumari's Discuss on draft-ietf-bfd-yang-16: (with DISCUSS and COMMENT)
Thread-Topic: Warren Kumari's Discuss on draft-ietf-bfd-yang-16: (with DISCUSS and COMMENT)
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Date: Wed, 04 Jul 2018 18:05:36 +0000
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I’m fine with adding “(and not admin-down)” to make it more explicit. Updated descriptions will be in the next rev.

Regards,
Reshad.

From: Warren Kumari <warren@kumari.net>
Date: Wednesday, July 4, 2018 at 2:03 PM
To: "Reshad Rahman (rrahman)" <rrahman@cisco.com>
Cc: The IESG <iesg@ietf.org>, "draft-ietf-bfd-yang@ietf.org" <draft-ietf-bfd-yang@ietf.org>, Jeffrey Haas <jhaas@pfrc.org>, "bfd-chairs@ietf.org" <bfd-chairs@ietf.org>, "rtg-bfd@ietf.org" <rtg-bfd@ietf.org>
Subject: Re: Warren Kumari's Discuss on draft-ietf-bfd-yang-16: (with DISCUSS and COMMENT)



On Wed, Jul 4, 2018 at 1:49 PM Reshad Rahman (rrahman) <rrahman@cisco.com<mailto:rrahman@cisco.com>> wrote:
Hi Warren,

Thanks for the review.
In your example below
                 +--ro number-of-sessions (10)
                 +--ro number-of-sessions-up (2)
                 +--ro number-of-sessions-down (5)
                 +--ro number-of-sessions-admin-down (3)

There is a description on Page 37 of rev-16 of the draft, I can add to it as follows, is this sufficient?

​Thank you, I checked there, and I don't *think* that this quite covers it.
The below *implies* that ​admin-down is not counted in 'number-of-sessions-down' (which is only 'down or init' state), but I think it could be clearer.


Perhaps:
leaf number-of-sessions-down {
        type yang:gauge32;
        description "Number of BFD sessions currently in down or init state (and not admin-down) (as defined in [RFC5880]).";

}


Does that work, or is it too long?
W

      leaf number-of-sessions {
        type yang:gauge32;
        description "Number of BFD sessions.";
      }
      leaf number-of-sessions-up {
        type yang:gauge32;
        description "Number of BFD sessions currently in up state (as defined in [RFC5880]).";
      }
      leaf number-of-sessions-down {
        type yang:gauge32;
        description "Number of BFD sessions currently in down or init state (as defined in [RFC5880]).";
      }
      leaf number-of-sessions-admin-down {
        type yang:gauge32;
        description
          "Number of BFD sessions currently in admin-down state (as defined in [RFC5880]).";
      }

I will fix the nits in the next rev.

Regards,
Reshad.

On 2018-07-04, 1:17 PM, "Warren Kumari" <warren@kumari.net<mailto:warren@kumari.net>> wrote:

    Warren Kumari has entered the following ballot position for
    draft-ietf-bfd-yang-16: Discuss

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    ----------------------------------------------------------------------
    DISCUSS:
    ----------------------------------------------------------------------

    Don't panic, this should be an easy DISCUSS to clear, but I think it important
    for interoperability.

    In multiple places, you have:
                 +--ro number-of-sessions?
                 +--ro number-of-sessions-up?
                 +--ro number-of-sessions-down?
                 +--ro number-of-sessions-admin-down?

    I'm a little confused by the meaning of the counters, and didn't see them
    clearly defined anywhere. Apologies if I missed it...

    Are "number-of-sessions-admin-down" included in "number-of-sessions-down"?
    Is 'number-of-sessions' always equal to 'number-of-sessions-up' +
    'number-of-sessions-down', or is it always equal to 'number-of-sessions-up' +
    'number-of-sessions-down' + 'number-of-sessions-admin-down', or are there other
    cases?

    E.g: I have created 10 sessions (because I have 10 interfaces). 5 of them are
    down because there is no peer, 3 of them I've configured to be down (admin
    down), and so 2 of them are up.

    What should be in each of:
    number-of-sessions?
    number-of-sessions-up?
    number-of-sessions-down?
    number-of-sessions-admin-down?


    ----------------------------------------------------------------------
    COMMENT:
    ----------------------------------------------------------------------

    Thank you.

    I also had a few minor nits:
    Nits:
    Section 1:
    "The YANG modules in this document conform to the Network Management Datastore
    Architecture (NMDA) Network Management Datastore Architecture [RFC8342]. " The
    Department of Redundancy Department called and wants some of their words back
    please :-)

    Section 2:
    "Since BFD is used for liveliness detection of various forwarding
       paths, there is no uniform key to identify a BFD session.  So the BFD
       data model is split in multiple YANG modules where each module
       corresponds to one type of forwarding path."
    I think this would be more readable as:
    "... to identify a BFD session, and so the BFD..."  (hey, I said it was a nit)





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