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Re: Last Call: <draft-ietf-intarea-ipv4-id-update-05.txt> (Updated Specification of the IPv4 ID Field) to Proposed Standard

2012-07-18 13:30:23

On Jul 17, 2012, at 11:16 PM, Masataka Ohta wrote:

Joe Touch wrote:

Or, are 6 to 4 translators are required to rate limit and
drop rate-violating packets to make the "stateless"
translators full of states.

I would expect that the translator would be responsible
for this, though

Do you mean translators must rate limit, or translators
violate RFC2765:

Translators violate RFC791. They cannot merely copy the low-order bits of the 
field, since that is insufficiently unique, and isn't specified as being 
generated at the IPv6 source in compliance with IPv4 requirements.

there is the problem that multiple translators interfere
with each other.

Yes, even rate limiting translators may interfere each other,
which means rate limiting must be done at the IPv6 source
node.

Regardless, this is outside the scope of the ipv4-id-update doc.

In the ID, there are a lot of references to IPv6.

It quotes IPv6 examples, but does not propose to change IPv6 processing. That 
may be needed, but that would be outside the scope of this doc.

For example, the following statement of the ID:

  Finally, the IPv6 ID field is
  32 bits, and required unique per source/destination address pair for
  IPv6, whereas for IPv4 it is only 16 bits and required unique per
  source/destination/protocol triple.

must be modified as:

  Finally, the IPv6 ID field is
  32 bits, but lower 16 bits are required unique per
  source/destination address pair for
  IPv6,

That's incorrect as per RFC2460. Other RFCs may violate that original spec, but 
that needs to be cleaned up separately.

Joe

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