Wojciech,
Le 21 juil. 2011 à 12:37, Wojciech Dec a écrit :
(with my typos corrected)
>>>> ...
>>>>
>>>> Host
>>>> H
>>> +-+ router
>>> | |< 2001:db8:a::
>>> | |--------------. .-.
>>> | | | | |< 2001:db8:a::/64 4V6T CE
>>> +-+ LAN |--| |-----------------. +-+
>>> | | | | | |< 2001:db8:a:/56
>>> --------------' '-' LAN |---| |------------
>>> | +-+ <= IPv6 packet
>>> ----------------' sent to host H
>
> ... Your diagram (...) shows the routers either without an
> IP address, or with bogus subnetting (subnet 0 cannot be in two
> places/links).
The picture doesn't show a router IP address because it was unnecessary for the
explanation, but this doesn't imply there is none (everybody knows that each
interface must have at least one address!).
Similarly, the picture doesn't show the subnet ID of the rightmost LAN, but
this by no means imply that it should be 0 (everybody knows that all links that
have global link prefixes must have them with different values).
If the new picture below is insufficiently clear, please ask, rather than
making interpretations that don't make sense, and then objecting to them.
>> ... As you know, we both agreed, in an off-list discussion, that the IID of
>> 4V6 addresses would better be a 1 than a 0 ...
Here is now a more complete example (with 1 as IID of 4V6 addresses in view of
the above)
==============
Host router CE
+-+ Interface address Interface address
| |< 2001:db8:a::1 < 2001:db8:a:ffff::10
| |--------------. .-. Delegated prefix Interface address
| | | | |< 2001:db8:a::/64 < 2001:db8:0:a:4:5:6:7
+-+ |--| |-----------------. +-+ Assigned IPv6 prefix
| | | | | | < 2001:db8:a::/48
| '-' |---| |------------
LAN-2 | | +-+
Link prefix | <= packet X (IPv6)
2001:db8:a::/64 LAN-1 | <= packet Y (IPv4-in-IPv6)
Link prefix IPv6 destinations=2001:db8:a::1
2001:db8:a:ffff::/64
Both packets X (IPv6) and Y (IPv4-in-IPv6) reach the CE because of their IPv6
destinations start with the CE assigned prefix 2001:db8:a::/48.
Now:
- If the CE is 4V6T, how packet X reaches the host is unclear to me.
- If the CE is 4V6E,
. Packet X is submitted to ordinary IPv6 routing because its payload IS NOT
an IPv4 packet.
. Packet Y has its contents directly submitted to the CE NAT44 because its
payload IS an IPv4 packet. (The 4V6 address 2001:db8:a::1, never treated as a
destination on any IPv6 link, is in fact a "dummy address".)
===============
An explanation of how 4V6T can work, on a configuration as detailed as this
one, would be welcome.
It would help to reach common understanding.
Regards,
RD
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