Subject: Re: [RRG] Renumbering...

From: Robin Whittle <[email-masked]>
Date: Sat, 16 Aug 2008 20:53:27 +1000

Hi Iljitsch,

You wrote, in part:

> But I guess the real question is: how do we get users to renumber? No
> matter how easy we make it (short of it being completely transparent,
> which isn't going to happen as long as we overload the functions of the
> IP address), if user simply refuse to renumber we've gained nothing.

LISP, APT, Ivip, TRRP and Six/One Router are all intended to provide
stable, portable, multihomable address space for end-user networks
so they don't need to renumber when they use another ISP.

I think there is no prospect for making reliable, secure,
renumbering enough sufficiently easy that we can convince end-user
networks to adopt any scalable routing system which requires this.

> This is one of the reasons why I think we should make an id/loc solution
> such that the locators are stripped off by the ISP. If the users don't
> get to see the locators, they can't hardcode them and renumbering (of
> the locators at least) remains a possibility.

For LISP, APT, Ivip and TRRP, the hosts never have any idea of the
locator address - the address of the ETR.

In Six/One Router, when a host in a non-upgraded network gets a
packet from a host in an upgraded network the packet's source
address has already been translated (by the translation router at
the border of the source network) to a transit address.  Transit
addresses are locator addresses.  So this fails your test.

It is also possible for a host in an upgraded network to receive
such a packet using the transit address, but I don't understand why
this is necessary: bilateral mode when both networks are upgraded.

I asked Christian about this here:

  http://psg.com/lists/rrg/2008/msg02149.html

   - Robin

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