Re: [v6ops] Limiting the size of the IPv6 header chain (draft-ietf-6man-oversized-header-chain)

On 11/06/2013 15:21, cb.list6 wrote:
> On Jun 10, 2013 7:23 PM, "Fernando Gont" <fgont@si6networks.com> wrote:
>> Folks,
>>
>> We're currently editing the aforementioned I-D. So far, the I-D just
>> required that the entire IPv6 header chain be present in the first
> fragment.
>> Based on recent/ongoing discussions on the 6man and v6ops lists, there
>> seems to be quite a few folks pushing the idea of limiting the size f
>> the IPv6 header chain to some value (typically in the order of a few
>> hundred bytes).
>>
>> An earlier version of draft-ietf-6man-oversized-header-chain limited the
>> header chain to 1280 bytes, but this requirement was later removed.
>>
>> However, since then a number of folks have produced real world data
>> which indicates that packets "won't make it to the destination node" if
>> the header chain is larger than a few hundred bytes, and I believe that,
>> overall, our understanding of the problem and situation has increased
>> since then.
>>
>> My question to th wg is:
>>
>> 1) Do we want to limit the size of the IPv6 header chain?
>>
>> 2) If so, which limit should we pick?
>>
> 
> It's not the size, it is how you use it.
> 
> I would suggest "common types" be permitted (tcp, udp, sctp, icmpv6, frag,
> esp, ah) while anything else must be behind an esp. This ensures all
> parties agree that further arbitrary headers will only be processed by the
> concenting end systems.

Truly, you won't get consensus for that; it isn't realistic. I think we're
already very near consensus on an unconstrained limit in the 128/256
area.

    Brian

> 
> CB
>> Thanks!
>>
>> Best regards,
>> --
>> Fernando Gont
>> SI6 Networks
>> e-mail: fgont@si6networks.com
>> PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492
>>
>>
>>
>>
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