Marshall, and others,
I've now read the new draft:
http://tools.ietf.org/html/draft-ietf-6man-udpchecksums-01
This looks much more like what I expected, thanks.
I've got some concerns with the following para in Section 5:
Whenever originating a UDP packet, an IPv6 node SHOULD compute a
^^^^^^ - (1)
UDP checksum over the packet and the pseudo-header, and, if that
computation yields a result of zero, it must be changed to hex
FFFF for placement in the UDP header. IPv6 receivers SHOULD
^^^^^^ - (1)
discard UDP packets containing a zero checksum, and SHOULD log the
error. However, some protocols, such as lightweight tunneling
protocols that use UDP as a tunnel encapsulation, MAY omit
computing the UDP checksum of the encapsulating UDP header and set
it to zero, subject to the constraints described in
[I-D.ietf-6man-udpzero]. In cases where the encapsulating
protocol uses a zero checksum for UDP, the receiver of packets
sent to a port enabled to receive zero-checksum packets MUST NOT
^^^^^^^^ (2)
discard packets solely for having a UDP checksum of zero. Note
that these constraints apply only to encapsulating protocols that
omit calculating the UDP checksum and set it to zero. An
encapsulating protocol can always choose to compute the UDP
checksum, in which case, its behavior should be as specified
originally.
^^^^^^^^^^ - (3)
(1), I think they MUST do this unless the receiver has been explicitly
enabled to process zero checksums for a particular port.
I think this sentence could be misleading, in that it can be quoted out
of context easily, better to say MUST unless the update specified later
is used. After all, the update proposed is
(2) I don't think this is a requirement you can easily place as an update
to RFC 2460.
(3) I think this means the method defined in RFC 2460.
In addition, I do think we should clearly recommend the use of checksums
when there are not specific reasons for disabling them.
I also see one minor NiT:
- The abstract should mention RFC 2460 in words, but not cite it as a
reference.
---
I look forward to your thoughts on this,
best wishes,
Gorry
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