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Re: Is Fragmentation at IP layer even needed ?

Brian E Carpenter <brian.e.carpenter@gmail.com> Mon, 15 February 2016 18:43 UTC

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Subject: Re: Is Fragmentation at IP layer even needed ?
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From: Brian E Carpenter <brian.e.carpenter@gmail.com>
Organization: University of Auckland
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Date: Tue, 16 Feb 2016 07:43:23 +1300
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On 15/02/2016 17:00, Joe Touch wrote:
> 
> 
> On 2/13/2016 5:26 PM, Masataka Ohta wrote:
>> QoS (not CoS but real QoS) capable routers must inspect L4.
> 
> That must be why there are QoS indicators in the L4 header.
> 
> Oh, wait - those are in L3 (RFC2474 and its successors).
> 
> Yes, layering is a difficult concept.

That's also why the IPv6 flow label is recommended to be a hash
of layer 3 and layer 4 information (RFC 6437, yes, it took us some
years to get that ~right).

   Brian

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