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From: Carsten Bormann <cabo@tzi.org>
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Date: Fri, 14 Nov 2014 06:05:23 -1000
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To: robert.cragie@gridmerge.com,
 Routing Over Low power and Lossy networks <roll@ietf.org>
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Cc: Pascal Thubert <pthubert@cisco.com>, "6tisch@ietf.org" <6tisch@ietf.org>, 
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Subject: Re: [6tisch] [Roll] [6lo] FW: New Version Notification for
 draft-thubert-6lo-rpl-nhc-02.txt
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On 14 Nov 2014, at 05:46, Robert Cragie <robert.cragie@gridmerge.com> =
wrote:
>=20
> Question - any reason the value 010001XY was chosen for the escape =
code?

Note that the escape space is not taken just for RFC 6553 compression; =
it can be used for encoding other NHCs as well.

The idea was to reserve some space around that so if we want to extend =
the escape space for some future NHC, we can do so while keeping it =
contiguous.

Note also that RFC 6282 already has variable length processing for hop =
limit and address compression, so the impact of adding a third instance =
is going to be limited.  (I need to write that up some more in =
draft-*-lwig-6lo.)

Since just about every data packet in a RPL network will carry an RPI, =
saving a single byte is worth quite some effort.

Gr=FC=DFe, Carsten