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Re: [AVTCORE] Comments on draft-ietf-avtcore-rfc5764-mux-fixes-03.txt

"Gonzalo Salgueiro (gsalguei)" <gsalguei@cisco.com> Tue, 20 October 2015 17:12 UTC

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From: "Gonzalo Salgueiro (gsalguei)" <gsalguei@cisco.com>
To: Paul Kyzivat <pkyzivat@alum.mit.edu>
Thread-Topic: [AVTCORE] Comments on draft-ietf-avtcore-rfc5764-mux-fixes-03.txt
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Date: Tue, 20 Oct 2015 17:05:32 +0000
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Cc: Marc Petit-Huguenin <petithug@acm.org>, "avt@ietf.org" <avt@ietf.org>
Subject: Re: [AVTCORE] Comments on draft-ietf-avtcore-rfc5764-mux-fixes-03.txt
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Thanks, Paul.  We’ll try and formulate this section so that it is more of a simple table look-up without attempting to overlay any predetermined look-up algorithms or efficiencies.

Cheers,

Gonzalo



> On Oct 20, 2015, at 12:09 PM, Paul Kyzivat <pkyzivat@alum.mit.edu> wrote:
> 
> On 10/20/15 6:49 AM, Magnus Westerlund wrote:
> 
>> 3.  Section 1.4:
>> 
>> I still don't see how what is written in this section results in any
>> improvement. You authors have assumptions of how this needs to be
>> implemented that isn't written down. Looking on this problem of
>> demultiplexing I would build a table driven solution based on the
>> ranges, where the packet is sent to the relevant protocol based on the
>> table-lookup. If that protocol don't use that value, that will be the
>> end of the road for that packet as invalid, rather than giving it to any
>> other protocol. I get the impression that you want one to send the
>> packet for testing by the protocols one after each other according to
>> the order the protocols are listed. I still don't see that
>> implementations will do that.
> 
> This has been my concern as well.
> 
> Look at it this way:
> 
> A natural implementation of this is via a switch statement. Each disjoint range of values is one case. (Detailed syntax varies by language.) A simple implementation of this may be implemented as a sequence of comparisons - a series of if/then/else such as you describe. a more time-optimal implementation uses a table lookup.
> 
> You shouldn't be mandating how this be implemented - only what the result is.
> 
> 	Thanks,
> 	Paul
> 
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