Re: [Casm] prefix assignment

Brian E Carpenter <> Wed, 29 March 2017 20:46 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 0728D12785F; Wed, 29 Mar 2017 13:46:53 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -2.7
X-Spam-Status: No, score=-2.7 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_LOW=-0.7, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Authentication-Results: (amavisd-new); dkim=pass (2048-bit key)
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id 9FhHh5gQwgGt; Wed, 29 Mar 2017 13:46:51 -0700 (PDT)
Received: from ( [IPv6:2607:f8b0:4001:c0b::241]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 0A6A912956C; Wed, 29 Mar 2017 13:46:51 -0700 (PDT)
Received: by with SMTP id w11so3643529itb.0; Wed, 29 Mar 2017 13:46:51 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20161025; h=subject:to:references:cc:from:organization:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding; bh=F60E85dKcF87/QWxtPhnnfRjuZXf/80TvUSMYICj9KM=; b=JAkNKRsUcHo8rNy1i27TOoSdw6rSe2R2mXtSTF4pvLMp+ZyfWgSRKFudHkfsWIdV5r JjJAItJ4D+yQWn1KE1Pyaph25j7yxPU3l5AaN6C3zDnm/iMGxIzMbV2LpwgLoUQ30ggz ltZJ4duHOQaZl8FH4/fpPO9rJ6WNTWXaCwk1hiNkhbic67sxtw/1c04EFviwG4lsF/Yt xWMlO9koZ6lyKf0Yic6A72YdEOjRrH3fFadi1FkOd6t2wrGlj6ucWtImN9D9HI71QDxS fWIosHx6bmAvn+orvkqJHRQiZTrj75BMMAP8N3Qk8WjroPb90QImOuSGFycasgxZeDoX HyGQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20161025; h=x-gm-message-state:subject:to:references:cc:from:organization :message-id:date:user-agent:mime-version:in-reply-to :content-transfer-encoding; bh=F60E85dKcF87/QWxtPhnnfRjuZXf/80TvUSMYICj9KM=; b=kHLLRAIhmXVNPlJoZZa52m/U5XxjWKVg1gp8f8mr+J5AZs/vs/KOU0ccTFP7EvaZVd cy6gg1PR5xaFONJtavQUsY+3FApb43kzzqLAhfzLllUj3fR14jn/PbK0vQixm6MB9JW7 HtC2ftGiXfNe6fNrIRlZgaHDIWLtgrbhIpy7RlrRk9rXTbV3PC7hLDEbFI4U5Xt1tXmU jS637QvietE7JWpq9k/csPjsaezRAxEd5ATk+RR9CIhmmUUO/hyiSBRGHvMxGmladNtW YJAf+vxR18NirAvht85RkQSp4MQOa66dyW4PKfSo3Xe7qlll6zYYzNW6auU3tzK8iLEL sCNA==
X-Gm-Message-State: AFeK/H1ln8V7TJidnqP+7Kbp/nwvlH0VQ4tU3224Qb/F/OTw5dvCrGOLRFJVCrIGFNh+aQ==
X-Received: by with SMTP id c124mr409142itc.17.1490820410424; Wed, 29 Mar 2017 13:46:50 -0700 (PDT)
Received: from ?IPv6:2001:67c:370:128:28cc:dc4c:9703:6781? ( [2001:67c:370:128:28cc:dc4c:9703:6781]) by with ESMTPSA id q185sm3893461itc.22.2017. (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 29 Mar 2017 13:46:49 -0700 (PDT)
To: Michael Richardson <>
References: <> <> <> <> <> <> <> <> <> <> <>
Cc:,, Mark Townsley <>,
From: Brian E Carpenter <>
Organization: University of Auckland
Message-ID: <>
Date: Thu, 30 Mar 2017 09:46:54 +1300
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0
MIME-Version: 1.0
In-Reply-To: <>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Archived-At: <>
Subject: Re: [Casm] prefix assignment
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: Coordinated Address Space Management <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Wed, 29 Mar 2017 20:46:53 -0000

On 30/03/2017 09:16, Michael Richardson wrote:
> 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.

No, it's not really Pythonesque but negotiation is allowed to fail.
> I just don't see the point of the ASA here.

There's already a thing called an HNCP agent. Why couldn't
it be enhanced to negotiate with an upstream ASA for resources?

> 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.

No disagreement; the idea was simply to ensure that the GRASP objective
can communicate that PD is or isn't available. If PD is required in
a particular scenario then that parameter will always be set True.
>     > 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.

Yes, I see that. (Unless of course we get into much more complex validation
and authorization stuff, which seems unlikely to fly.)