[lisp] Resolving Issues #9, #10 and #12? (UDP Checksums)

[Margaret Wasserman <[e-mail]>]

Now that the UDP checksum issues have been entered into the tracker, I
think we can try to agree to a resolution for the following issues:

Issue #9 Sending UDP Zero Checksums Violates RFC 2460
Issue #10 Sending UDP Zero Checksums not Universally Implemented
Issue #12 Not Checking Inbound Non-Zero Checksums not Universally  
Implemented

Sam had proposed some wording earlier, and Dino had offered to put it
in the -04 draft.  I then suggested that we add a normative reference
to Marshall Eubanks' IPv6 zero UDP checksum draft to allow sending
zero UDP checksums in IPv6.  Noel objected to making it optional to
ignore UDP checksums because of concerns that widely-deployed NATs
would corrupt a zero UDP checksum and packets could be black-holed.
Since then, we have determined that those NATs change the UDP checksum
to a correct checksum value, so that concern has been eliminated.

So, at this point, I think we may have agreement on the following
changes:

OLD (-03 version):

UDP Checksum: this field MUST be transmitted as 0 and ignored on
               receipt by the ETR. Note, even when the UDP checksum is
               transmitted as 0 an intervening NAT device can
               recalculate the checksum and rewrite the UDP checksum
               field to non-zero. For performance reasons, the ETR MUST
               ignore the checksum and MUST not do a checksum
               computation.

NEW (proposed -04 version):

UDP Checksum: this field MAY be transmitted as 0 in both IPv4 and IPv6
               packets [draft-eubanks-chimento-6man-00.txt], and MAY be
               ignored by the ETR.

+ Add a normative reference to draft-eubanks-chimento-6man-00.

Does anyone object to making the change shown above to resolve issues
#9, #10 and #12?

Margaret