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

Tero Kivinen <> Wed, 15 October 2014 15:21 UTC

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Date: Wed, 15 Oct 2014 18:21:11 +0300
From: Tero Kivinen <>
To: Markus Stenberg <>
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References: <> <> <> <20141014142746.GX31092@Space.Net> <> <20141014145930.GY31092@Space.Net> <> <> <> <> <>
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Cc: Ted Lemon <>, Pierre Pfister <>, Erik Kline <>, HOMENET Working Group <>, Gert Doering <>, Mikael Abrahamsson <>
Subject: Re: [homenet] Let's make in-home ULA presence a MUST !?
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Markus Stenberg writes:
> Because no matter what ISP does, my IPv4 prefixes in my home _are_
> stable. And IPv6 ones too (thanks to using statically configured
> tunnel, cough).

When we defined a recommendation for ISPs in Finland for IPv6, we
suggested that ISPs should always give same prefix to same customer,
and when giving out the addresses, they should set the preferred
lifetime to 7 days, and valid lifetime to be 30 days, i.e. even if the
network connection is down for several weeks, the IPv6 addresses
inside the house are still usable. Of course if there is power outage
and every device in the network looses power, and there is no network
connectivity when they come back up, that usually means there is no
valid IPv6 addresses anymore, unless they are statically configured
somewhere (or stored to the stable storage by the routers). 

> I would argue that flash renumbering is bad too, but I would also
> claim that overlap of less than session lifetime is not acceptable.
> .. some of my session lifetimes are in days (single TCP session). Or
> are we planning to ultimately deprecate TCP and advocate something
> else? MPTCP? Yes, I know typical home user has just HTTP requests,
> but I am not fond of idea of turning the network to
> short-lived-connections only model just because it seems currently
> the most popular way to do things. 

My ssh connections are usually up and running for ever. They only go
down when I update my firewall, there is network problems, or our
company firewall is reset for some reason. Usually that means the ssh
connection is up for few months... I would be very unhappy I would
need to restart my TCP connections every month, so any ISP giving me
such notwork, would not be consider as proper ISP, and I would
immediately switch to another ISP if my ISP starts doing things that
break my connections. 

> Every time I hear about ISP-forced customer renumberings, the more I
> start to think that 1+ ULA prefixes per home is a MUST, not a

Most of my long lived connections are from my office to my home, or
from my home to my summer house. I.e there are some connections inside
my home which are longlived, but also the global IP-addresses need to
be stable enough for my use cases, i.e. ULA would not help me that