Hi, On 2009-8-3, at 13:18, Rémi Després wrote:
In view of the various arguments made, here is IMHO a good combination:
...
- IPv6 hosts MAY accept UDP datagrams with zero checksum.
I see no reason why allowing a UDP checksum of zero for router-to- router tunnels under specific circumstances (existence of a payload checksum), which is what we've been discussing for AMT and LISP, motivates *any* changes for the host. As far as hosts as concerned, nothing changes with regards to RFC2460.
- IPv6 hosts that accept zero-checksum UDP datagrams MAY restrict this tolerance to remote hosts whose IPv6 addresses include an IPv4 mapped address. (Thus no new tolerance is introduced for IPv6 hosts.)
Since there is no IP header checksum in IPv6, these IP addresses can be corrupted, and so this check may fail.
- IPv4 to IPv6 translators that receive UDP datagrams with zero checksums MAY keep these checksums in translated datagrams.
Translators are not tunnels. The argument why a zero outer checksum may be OK for tunnels is that the inner payload is still protected by a checksum, which is not true for translators.
Lars
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