Re: 6MAN WG Last Call: <draft-ietf-6man-oversized-header-chain-04>

[Fernando Gont <[e-mail]>]

Hi, Mike

On 08/19/2013 09:58 PM, C. M. Heard wrote:
> 
> My main question is why this draft is not better integrated with 
> draft-wkumari-long-headers-01 and draft-bonica-6man-frag-deprecate, 
> which have overlapping or at least related subject matter.

Because what's in draft-ietf-6man-oversized-header-chain is what the wg
agreed upon over time.

For instance, some earlier version of
draft-ietf-6man-oversized-header-chain enforced an upper limit t the
size of the extension header length (1280 bytes, at the time) but such
limit was removed from the document in responses to wg consensus.


> The thrust of draft-wkumari-long-headers-01 is the claim that 
> operators have a requirement to filter at Layer 3 and Layer 4, at 
> line rate, in the network, and that in order to be able to do that, 
> the entire header chain needs to appear within a relatively short 
> initial segment of the IPv6 datagram -- the draft suggests 128 
> bytes.  This is MUCH shorter that the "within the first fragment" 
> constraint specified by draft-ietf-6man-oversized-header-chain.

And it was agred by this wg that this limit would be an operational BCP,
but not a protocol update. That's thy these items are kept in different
documents.




> There is also a strong hint (though not an explicit statement) in 
> draft-wkumari-long-headers-01 that entities that do in-network 
> line-rate filtering need to see layer 3 and 4 information in ALL 
> datagrams, which is at the heart of the subject matter of 
> draft-bonica-6man-frag-deprecate.

The wg discussed this, and I seem to recall that the outcome was that we
were not ready to ban the use of fragmentation, but rather that we
should move away from it.

Cheers,
-- 
Fernando Gont
SI6 Networks
e-mail: [e-mail]
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