On Aug 3, 2009, at 5:15 PM, Rémi Denis-Courmont wrote:
(1) UDP-Lite: Is there a reason why UDP-Lite isn't a reasonable
choice for LISP encapsulation? When we looked into this for CAPWAP
(another IP-in-UDP/IP tunneling case), we found that UDP-Lite would
meet our needs for IPv6, so we did not need to specify the use of
zero
UDP checksums.
You would expect 64-translators to convert UDP-Lite/IPv6 into UDP-
Lite/IPv4
and back. Converting UDP-Lite/IPv6-with-8-bytes-coverage into UDP/
IPv4-
without-checksum sounds hackish :(
Are we actually expecting 64-translators to exist between LISP routers?
In the more general sense, this is something you need to deal with,
because there are things out there that use UDP-Lite. I don't see the
transform you have suggested as any worse than just dropping the IP
header checksum when converting from IPv4 to IPv6 in cases where it is
not covered by a transport layer checksum.
(2) IP-in-IPv6: Why do you need the UDP encapsulation at all in
IPv6? In IPv4, you may need it for NAT traversal, but it is not
clear
that NATs will work the same way in IPv6. Or are there other reasons
why you need the UDP encapsulation?
(...)
Same problem. 64-translators would translate IP-in-IPv6 to IPIP and
vice
versa. IPIP does not go through NATs.
So, now we're running encapsulation protocols behind an IPv4 NAT _and_
a 64-translator? Ick.
That's why I was trying to suggest defining a new UDP-Lite-like
transport
protocol that would only be allowed over IPv6 and that 64-translator
would
convert into checksum-less UDP/IPv4.
Why is the current UDP-Lite protocol not okay for this?
Margaret
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