Re: [Casm] prefix assignment

Michael Richardson <> Wed, 29 March 2017 20:16 UTC

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From: Michael Richardson <>
To: Brian E Carpenter <>
cc:,, Mark Townsley <>,
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Date: Wed, 29 Mar 2017 16:16:28 -0400
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Subject: Re: [Casm] prefix assignment
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Brian E Carpenter <> wrote:
    > Where you want to plug in an ASA (autonomic service agent) is anywhere
    > you want plug in some intelligence to govern an automatic process.
    > Intelligence, for example, to figure out what to do if the user side
    > asks for a /48 and the ISP offers a /60. So the ASA might negotiate
    > a compromise at /56 and then PD does its thing. But we didn't want
    > to exclude a scenario where PD isn't available, hence a flag is
    > included.

To put this is pseudo-(monty)pythonesq:

Customer: Hi, I'd like to buy a parrot.
Store: Would you like a Blue Parrot or a Red Parrot?
Customer: I'd like a Blue Parrot.
Store: I'm sorry, but we don't sell Parrots.

I just don't see the point of the ASA here.

If DHCPv6-PD isn't available, then it's not a compliant ISP connection
(RFC7204) and it's outside of the scope of homenet to begin with.

    > About the domain boundary:

    >> I don't think that the ISP can trust to have code controlled by end users
    >> running in their ACP domain.

    > Right. But in ISP-provided CEs this could presumably be fixed, because
    > that code would be locked down. In a store-bought CE, isn't this exactly
    > where BRSKI will help us? There is certainly an issue for home-made CE
    > images, but they will be a tiny minority of users.

No, BRSKI doesn't help the ISP feel safe that the code I am running
on my store-bought CE won't attempt to mess with their network.

Michael Richardson <>ca>, Sandelman Software Works
 -= IPv6 IoT consulting =-