Re: [Roll] AD Review of draft-ietf-roll-mpl-parameter-configuration

Michael Richardson <> Tue, 16 June 2015 13:35 UTC

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From: Michael Richardson <>
To: "Alvaro Retana \(aretana\)" <>
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Date: Tue, 16 Jun 2015 09:35:07 -0400
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Cc: "" <>, "" <>, Ines Robles <>, "" <>
Subject: Re: [Roll] AD Review of draft-ietf-roll-mpl-parameter-configuration
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Alvaro Retana (aretana) <> wrote:
    > I just finished reading this document.

    > I think the document is almost ready to move forward — I have one
    > major comment (below) related to sending the Option as it relates to
    > the potential of mismatched options. I am going to start the IETF Last
    > Call, but expect at least a discussion about that comment before
    > putting the draft in front of the IESG.

Do you mean, if different parts of the network have different parameters?
I had that same question, and I asked it here:

    > rfc6206 talks about “unintended behaviors”). This document says
    > (Section 2.4) that "the server will send MPL Parameter Configuration
    > Option only if configured…and the client requested it”..and (Section
    > 2.2) says that a client "MAY request MPL Parameter Configuration
    > Option”. In summary, the server won’t send the Option unless the
    > client requests it; is that what is intended? Furthermore, the
    > request is optional (I’m assuming there may be resource
    > considerations here), so there may be cases in which not all clients
    > request the Option, resulting in potentially mismatched parameters.

Clients that don't ask for the option probably don't support it....

    > Am I interpreting the text correctly? If so, why was it specified
    > this way (instead of having the server send the Option (when
    > configured for a specific MPL Domain) always? Does the client then
    > require configuration to be able to request the additional
    > configuration parameters?

That's mostly how DHCPv6 works.  The client sends a list of options it
cares about, and the server answers them.  That seems the right thing to
do with constrained nodes on a challenged network.

    > * Instead, I would like to see some discussion about it in the
    > Operational Considerations section. Pointing to rfc6206 may be
    > enough to remind people who are implementing this Option.
    > * Related to this point: I recommend moving the discussion in
    > Appendix B to the Operational Considerations section.


Michael Richardson <>ca>, Sandelman Software Works
IETF ROLL WG co-chair.