Re: [multipathtcp] Options or Payload: pros and cons

"SCHARF, Michael" <Michael.Scharf@alcatel-lucent.com> Thu, 12 November 2009 01:57 UTC

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Date: Thu, 12 Nov 2009 02:57:53 +0100
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From: "SCHARF, Michael" <Michael.Scharf@alcatel-lucent.com>
To: "Costin Raiciu" <c.raiciu@cs.ucl.ac.uk>, <multipathtcp@ietf.org>
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Subject: Re: [multipathtcp] Options or Payload: pros and cons
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> Payload
> + option space limits no longer matter; can do funkier stuff later,
> like negotiate keys, etc.
> + easier to get reliability; retransmit of control data linked to
> data retransmit
> + easier to deal with middleboxes that resegment (it just works!) new 
> + options on syns may be allowed, but not on data (is this true)?
> - feels like a hack, not the traditional way to evolve tcp
> - implies encoding of any data sent MUST  be ASCII; 
> middleboxes (ids, traffic normalizers) that look at content 
> and see binary stuff will probably drop the data; finally, if 
> we used binary stuff, there is no guarantee for fate sharing. 
> . Text encoding is less space efficient; does it matter?

I don't understand why ASCII encoding is mandatory. An IDS that parses
the content may anyway be confused by the incomplete content inside one
MPTCP subflow, independent of the question whether options or payload
encoding is used. Or do I miss something?

Michael