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

Gert Doering <> Tue, 14 October 2014 15:46 UTC

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Date: Tue, 14 Oct 2014 17:46:06 +0200
From: Gert Doering <>
To: Ted Lemon <>
Message-ID: <20141014154606.GA31092@Space.Net>
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Cc: Erik Kline <>, HOMENET Working Group <>, Pierre Pfister <>, Gert Doering <>
Subject: Re: [homenet] Let's make in-home ULA presence a MUST !?
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On Tue, Oct 14, 2014 at 10:13:34AM -0500, Ted Lemon wrote:
> On Oct 14, 2014, at 9:59 AM, Gert Doering <> wrote:
> >> Indeed.   The question is, should we increase the number of instances in which they are forced to handle it, or no?
> > 
> > Because this is the only way that application developers will learn to
> > handle it.
> Application developers _can't_ handle it.   Applications have no control over routing, and making applications do source address selection is a really bad idea.

Application developers MUST handle changing addresses, for example by not
doing silly things like "at startup, do some DNS resolving and socket
binding to a fixed address, and assume that the addresses you receive
are not changing".

I haven't even mentioned source address selection, as that doesn't come
into play for a singlehomed homenet - but as soon as the homenet gets
multihomed, applications would benefit a LOT from doing intelligent
source address selection.  Like in presenting users a selection menu
"use ISP? -> SpaceNet, HE.NET, don't care" and picking the appropriate
source address.

Yes, there's quite a bit of specifications missing to be able to do that
(like, how do I find a label to stick onto an address I find on my 
interface), but for a *homenet*, this is the way it needs to be - nobody
will fiddle with the router to do "http goes to SpaceNet, bittorrent goes
to HE.NET", but if the application can do it, it greatly empowers users.

> I haven't encountered any ISPs that do flash renumbering, and I'm
> surprised to hear you saying that T-Online is doing it: that's not
> my understanding.   In general, providers that renumber their
> customers use graceful renumbering, not flash renumbering.   There's
> no reason to do flash renumbering.

In the end, at some point in time, the old prefix goes away, however
you phase it.  So if the application stubbornly clings to it, it will stop

Gert Doering
        -- NetMaster
have you enabled IPv6 on something today...?

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