Re: [homenet] Let's make in-home ULA presence a MUST !?

Brian E Carpenter <> Sat, 18 October 2014 04:25 UTC

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Date: Sat, 18 Oct 2014 17:25:38 +1300
From: Brian E Carpenter <>
Organization: University of Auckland
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To: Ted Lemon <>
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Cc: HOMENET Working Group <>, James Woodyatt <>
Subject: Re: [homenet] Let's make in-home ULA presence a MUST !?
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On 18/10/2014 11:37, Ted Lemon wrote:
> On Oct 17, 2014, at 5:16 PM, James Woodyatt <> wrote:
>> p1. It looks like you agree that locally generate ULA prefixes should be allowed to expire. What I don't see is any conceptual outline for deciding, in a distributed methodology, which prefixes to renew and which to release when their valid lifetime expires. Without seeing that, I can't agree that you've proposed anything that solves the problem I keep yammering about, much less offered a better solution than the one I proposed earlier in the thread.
> Please don't put words in my mouth.
> I did explain how to do that: before the network partitions, 

That seems to imply that you know in advance that the network
will partition. I assume that it will usually be a surprise.
Normally there is no human manager, although a human might
randomly disconnect cables or switch off a power socket.

So I think you mean: as soon as the network has generated its ULA...

> divide the ULA into 64k /64 prefixes, and distribute these evenly among attached routers.

...but that will break when another router attaches itself later,
unless the (re)distribution process is continuous.

>  Routers other than the ones that own a particular /64 are not allowed ever to use that /64 unless the router that owns it relinquishes it to them explicitly.

Sure, and this needs to be supported by HNCP (or something else).

>   Prior to partition, an agreement is made that one of the routers gets to keep the ULA in the event of a long-term partition. 

Again: that has to happen as soon as the ULA is generated, since partition
is unpredictable.