In message <[email protected]>, Mark Andrews writes:
>
> In message <01f401cd05dc$20914df0$61b3e9d0$@[email protected]>, "Marc Lampo" wri
> te
> s:
> > Allow me to clarify with an example.
> >
> > In my IP(v4) experience, I have a customer with offices over multiple
> > Continents - private address space in use everywhere -
> > site-to-site VPN's (== connecting networks) connect the offices.
> >
> > If I map to IPv6 this might be one /48 ULA range;
> > Some networks in central HQ, others remotely, behind site-to-site VPN.
> >
> > --> if one end-node in one network wants to reach another,
> > in another network, its traffic must travel through the VPN.
> >
> > Please observe that using public addresses (not using ULA)
> > might do away with address selection "challenges"
> > but would imply that networks on all continents will have to be
> > renumbered if the central HQ changes ISP (and hence : public IPv6
> > addresses).
> > Something I'd like to avoid ...
> >
> > Kind regards,
> >
> > Marc Lampo
>
> Well with a single ULA you have 65536 /64 sized networks to use
> where ever you want. You have ULA:0000/56 in Paris, ULA:0100/55
> in New York. You don't have to keep things bit aligned but it
> helps. 65536 prefixes isn't a lot of routing information. Think
> of it in IPv4 terms as 10/8 and you are handing out /24 for each
> subnet except you know you won't need more than /24 ever.
Alternatively you can give each site its own ULA and you use non
default address selection rules. Remember we are talking about the
default rules here. There are billions of more homes than there
are businesses.
They would use rules like the follow which give all the sites a
common label:
::1 50 0
ULA1:/48 45 100
ULA2:/48 45 100
ULA3:/48 45 100
::/0 40 1
2002:: 30 2
fc00:: 0 3
Whereas the default rules generate a table like if it was multi-homed
to three sites:
::1 50 0
ULA1:/48 45 4
ULA2:/48 45 5
ULA3:/48 45 6
::/0 40 1
2002:: 30 2
fc00:: 0 3
--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: [email protected]
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